Tool Post Grinders - Can A good one be made?

[simonl]

Hi all,

Thanks to the generosity of Argeng (Bruce) I have been lucky enough to have some time to play with a Sher tool post grinder. While I am yet to put it to some actual use (project wise) I have seen what a potentially valuable tool the y can be in the absense of a cylindrical grinder or equivalent attachments on a t&c grinder.

Looking at tool post grinders on ebay, Doall and other types sell for some silly amounts of coin. However, a second hand spindle from one of these can be bought for less than $100 leaving only the motor and some type of frame or attaching system to be made.

I have searched the forum and there have been some discussion about it but nothing concrete. I want to know peoples thoughts on say purchasing something like this:http://www.ebay.com.au/itm/Themac-420e-Spindle-Assembly-Lathe-Tool-Post-Grinder-45-000-RPM-/251942812950?pt=LH_DefaultDomain_0&hash=item3aa8f63d16

And perhaps coupling it with sometging like this:http://www.aliexpress.com/item/1pcs-400w-high-speed-spindle-motor-air-cooled-motor-DC-spindle-collet-for-cnc-engraving-machine/1874379794.html

Is this idea bound to end in disappointing results? Any thoughts?

Simon

[bollie7]

Simon
I dont think this will end in dissapointment. Just depends on how much effort you put into it. Just have to make it rigid enough. I'm sure there would be a wide choice of motors available. You could possibly even use an air die grinder as your motor. At least for an internal grinding spindle anyway. Keep in mind for external grinding you are not going to need the speed on the wheel that you would need for internal (smaller dia stone).
Go for it.
bollie7

[mahgnia]

Simon,

If you can buy one that works well, you should be able to make one that works as well or better, to suit your lathe.
Things to focus on are rigidity, good lathe bearings, rigidity, smooth grinding wheel drive motor/pulleys/belts (eliminate vibration), and also dare I mention it, rigidity.

Also helps to consider being able to grind tapers between centres without interference from the tailstock.

Good Luck.

Andrew

[KBs PensNmore]

Hi Simon, I dare say that using the components shown, YOU would make a fantastic one. A WIP report is a must though.:D
I used a Dremel with a flexidrive, to get inside the ER25 collet I made, and it worked well, except that it wasn't all that rigid!! Wondering if one with a VS motor would be more beneficial, as that way for using small stones could be sped up and for outside work slowed down, either that or 2-3 speed?????
Kryn

[malb]

My father made one maybe 40 years ago to use on his 9in Southbend. His had interchangable spindles for internal and external work, and was belt driven from a sewing machine motor, different drive ratios for the different spindles.

From memory, he used wheels abt 3 x 1/2 for external grinding, and points between 1/4 and 3/4 for internal work. The housing was similar to a couple of Waldown units that I recently spotted on ebay or gumtree, and the external spindle could be installed facing the headstock or tailstock to minimise interference between saddle and headstock/tailstock when grinding to the end of a workpiece. I presume that the internal spindle could also be reversed, but never saw it operating in that mode, which I suspect would be rather redundant.

The unit was rather underpowered but otherwise quite successful for my father's requirements, and was retained and used fairly regularly until his eyesight failed in his 80's and he stopped using the lathe. It is probably somewhere on the sunshine coast still, most likely rusting away in my BIL's wallless shed along with the rest of his tool collection.

[TheNutter]

Hi Simon

This was with my lathe when I bought it. I assume that it was made by the previous owner. It fits into the the four way tool post. It appears to have been well used, there are plenty of dings from the tool post bolts on the plate. Apart from the wiring the whole thing looks and feels good. The base is a piece of 1/4 plate with a stiffener welded onto the bottom. The spindle is held by a couple of machined ring clamps which are welded to the base plate.

It is a small universal motor, the wiring is very dodgy and apart from cutting the plug off I have never done anything with it. The DC motor that you identified looks like the go and if you do a WIP I will follow with interest and might convert it.

Let me know if you would like some more detailed photos.

Regards

Ian


348517

[KBs PensNmore]

Hi Ian, I don't know about Simon wanting more pics of details, but I wouldn't mind seeing more details, PLEASE.:2tsup:

[simonl]

Thanks guys. More pics from Ian would be good! Don't get too excited about a WIP. 80% of my brain ideas end up nothing more than an idea, it's only a small percentage that actually get made!

But still, I am intetested in the idea of making one. Probably the hardest part is deciding on which S/H spindle to buy. The one I attached here is rated to 45K, that seems like way more than I need (on the surface) but when you calculated the required RPM needed to maintain say 5000 sfm it becomes clear that external grinding with a 75mm wheel requires about 6500 rpm, Thats pretty easy to achieve even I could make a spindle to do that. However, if I wanted to do some internal grinding using say a 1/2 wheel for a MT or something, the requires about 38K. Lets face it, the required sfm is achieved with a fast lathe speed since my lathe has a max rpm of 1500 rpm, so at max speed I would need 36500rpm.

I see some spindles are rated to 12K or 24K. Does this mean they came with a TP grinder that had maybe two spindles, one for internal and one for external grinding? If this is the case then would a higher speed spindle, like the one I attached (which is rated to 45K) be unsuitable for external grinding because it would be too small in shaft diameter, creating flex?

These are things I have no idea about and need to work out before I hand over my hard earned on parts for a project I will be disappointed in...

Just thinking aloud. I hope thinking is allowed. :B

Cheers,

Simon

[Anorak Bob]

Hello Simon,

I have a Dumore TPG. - http://www.woodworkforums.com/showthread.php?t=129051&p=1254573#post1254573 I don't use it for a number of reasons most of which are contained within that thread and a couple of related threads.

They are messy, the grinding less messy than the wheel dressing. This photo shows some of the wheel dust on the chuck and on the sheet of rubber covering the ways.


http://www.woodworkforums.com/attachment.php?attachmentid=179095&d=1313307736

The dust is all pervading. I covered the entire lathe with plastic painter's drop sheets in a effort to protect the lathe. Operating the lathe while covered isn't really convenient neither is dismantling and cleaning the chuck and the saddle after grinding. The Hercus with its overhead drive is an awkward thing to cover properly, other lathes are probably easier to protect, that's if you are worried out protecting it.

I do have a Dumore manual that I can copy and send to you.

Interestingly, Schaublin among others, offered a selection of grinding spindles for their lathes. They were either saddle or vertical slide mounted and driven via an overhead pulley arrangement from an independent motor. Another problem with a tool post grinder is its physical size which on a small lathe like my Hercus, can obstruct vision and access. Schaublin's setup doesn't.

All that said and done, I have a second Dumore 44 that you can have if you are interested. The motor is rooted and I imagine the spindle bearings are no better. I bought it from the States, the seller describing its condition as "good" ( doesn't good come in all shapes and sizes!!! ). If you are interested I will snap a few photos.

BT

[Oldneweng]

One of the first projects I started when I got a lathe was a tool post grinder. The bits I managed to make are still waiting in a box under the mill.

I presume your intention is to use a belt to drive the spindle from the motor and acheive the speed increase. When I looked at the motor, I thought it would make a perfect grinder on its own except limited to 12k rpm. It comes with an ER11 chuck to mount any wheel on a shaft up to 7mm diam.

I am thinking (yes, I think it is allowed) that I could buy one of these motors to use on its own as an external grinder and use the die grinder as suggested some time back by Nearnexus for internal work. This would be quick and easy, which is great in my case as I have a huge backlog of work to do.

On the other hand, you could keep looking and see if you can find a motor that will do both.


80% of my brain ideas end up nothing more than an idea, it's only a small percentage that actually get made!

You too. A lot of my ideas get started and put aside until later and when later comes, the situation has changed. I have many bits around that I know I cut up for something, but what? I also have many bits that I know what they are for. I have a plan to put these project bits in a 15l plastic bucket (I have dozens), label it and put it on the shelf. One of the issues here is that all my shelves are overflowing already. Another project that.

Dean

[simonl]

Hello Simon,

I have a Dumore TPG. - http://www.woodworkforums.com/showthread.php?t=129051&p=1254573#post1254573 I don't use it for a number of reasons most of which are contained within that thread and a couple of related threads.

They are messy, the grinding less messy than the wheel dressing. This photo shows some of the wheel dust on the chuck and on the sheet of rubber covering the ways.


http://www.woodworkforums.com/attachment.php?attachmentid=179095&d=1313307736

The dust is all pervading. I covered the entire lathe with plastic painter's drop sheets in a effort to protect the lathe. Operating the lathe while covered isn't really convenient neither is dismantling and cleaning the chuck and the saddle after grinding. The Hercus with its overhead drive is an awkward thing to cover properly, other lathes are probably easier to protect, that's if you are worried out protecting it.

I do have a Dumore manual that I can copy and send to you.

Interestingly, Schaublin among others, offered a selection of grinding spindles for their lathes. They were either saddle or vertical slide mounted and driven via an overhead pulley arrangement from an independent motor. Another problem with a tool post grinder is its physical size which on a small lathe like my Hercus, can obstruct vision and access. Schaublin's setup doesn't.

All that said and done, I have a second Dumore 44 that you can have if you are interested. The motor is rooted and I imagine the spindle bearings are no better. I bought it from the States, the seller describing its condition as "good" ( doesn't good come in all shapes and sizes!!! ). If you are interested I will snap a few photos.

BT

Hi Bob,

I read your thread when I did my search. I always attempt a search before starting a thread just to make sure it's not all been done to death prior. I noted that you had initial problems with your finish but you got it sorted with the bearing preload.

I camm appreciate the mess when grinding now that I have a sg, which I ALWAYS use with coolant as well. Wheel dressing causes more mess than I could ever have imagined. At least sg are designed for this and care has been exercised in the protection of their ways, not so with a lathe. Yes, I need to protect my lathe ways, it may be Chinese but it's all I have!

I certainly would be interested in some pics, at your convenience. No rush. As per my previous confession, many of my projects just never take off and the ones that do can sit for a number of (sometimes) years before I decide they are no longer a nice to have but now I need to have!

Hi Dean,

I'm glad I'm in good company with finished projects! My recent ball turner only took 12 months, but I knew it was there waiting to be finished. I just had it in a holding pattern. :rolleyes: Actually, I now need it because my friend wants me to make him a new gear knob for his Patrol.

Yes, I have discounted the idea of a direct drive TP grinder eventhough there are a plethora of DC and other brushless types of motors with an included ER11 collet which would seem all too easy. However, I'm just concerned that the bearing quality and spindle design would not be condusive to the kind of finish I am looking for. There I think they may make a good drive motor but coupled to a dedicated quality spindle.

My other option, if I don't want to committ to a motor AND spindle is to just purchase a spindle and gerry rig a trimmer router I already have. It does 30K no load but with a speed controller could be made to any speed to probably 8K. It's small and has a collet which would make a temporary pulley fitment very easy. It's also compact and small and would be very easy to temp mount it.

Simon

[Hunch]

Mate has an old Dumore 44 I can't see him ever using and might be willing to offload too - must be from the 30s or 40s going by the list prices in the box.

[simonl]

Mate has an old Dumore 44 I can't see him ever using and might be willing to offload too - must be from the 30s or 40s going by the list prices in the box.

Thanks for the offer. You can ask what he wants for it but if it's even reasonable then I doubt I can afford it ATM.

Cheers

Simon

[pipeclay]

Most of the Tool Post griders will come with a selection of drive pullys to achieve desired RPM.

[simonl]

Most of the Tool Post griders will come with a selection of drive pullys to achieve desired RPM.

Thanks PC. I had noticed that. I also get the impression that to do very small internal grinding requires a very expensive and high reving spindle.

Another cheap option for a motor is this on ebay. I could even pick it up but for $15 delivery I probably wouldn't bother. Being a vacuum cleaner motor, I dare say it probably revs to about 12K and it looks like the air flow is from the front, meaning it would force air out the side rather than ingest grinding dust from the rear. It's only about 260W though. It looks old and it's made in Sweden, another reason to like it! :D

http://www.ebay.com.au/itm/291476689352?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Simon

[TheNutter]

Some more photos of the tool post grinder. I probably shouldn't try for new career as a photographer...

348626

The machined bands wrap around the spindle, they are welded to the plate on the left hand side and a pinch bolt is threaded through the base plate to the right of the spindle.

348628

From underneath. That stiffener bar is a later addition, there is a shorter one on the top. By the look of this the whole thing needs to have been made stiffer from scratch. Perhaps something thicker that 1/4 plate as a base.


348629

Another view showing the bands that hold the spindle.

348630

From the other end. I suspect that the motor is from one of those old black fans.

Happy to try and answer any questions.

Regards

Ian


348626348628348629348630

[Anorak Bob]

A few photos of the giveaway and the keeper. The armature pictured is from the latter. I swapped armatures because a number of the balancing weights were missing from the keeper's original armature.

With the correct pulley combination, it was originally good for 38,000 RPM.

With the motor removed and dumped in the Sulo bin, the remainder should fit in a Parcel Post bag. That's if you want it.
And Simon, it can sit in your shed for another ten years before you chuck it out.http://d1r5wj36adg1sk.cloudfront.net/images/smilies/happy/biggrin.gif

BT

[simonl]

A few photos of the giveaway and the keeper. The armature pictured is from the latter. I swapped armatures because a number of the balancing weights were missing from the keeper's original armature.

With the correct pulley combination, it was originally good for 38,000 RPM.

With the motor removed and dumped in the Sulo bin, the remainder should fit in a Parcel Post bag. That's if you want it.
And Simon, it can sit in your shed for another ten years before you chuck it out.http://d1r5wj36adg1sk.cloudfront.net/images/smilies/happy/biggrin.gif

BT

Thanks Bob. That's a very generous of you. Have you thought about taking the motor to a motor reconditioner and getting it overhauled and re-balanced? You could possibly on sell it and recoup your money? Just a thought. Not trying to talk you out of sending it my way of course :D, I'm quite happy to pay what you think would be a fair price. In any case, it's a wonderful offer and I'm keen. It would give me a good basis or starting point to work from.

Hi Ian, thanks for the pics. You mention the rigidity issues from the base plate but but it looks like a fair amount of thought and effort went into building that.

Cheers,

Simon

[Anorak Bob]

Simon,

I will weigh the grinder with and without the motor tomorrow. The grinder that I am giving away for FREE is the one with the chipped paintwork and the disassembled rooted motor.

This one.

http://www.woodworkforums.com/attachment.php?attachmentid=348641&d=1432980103

There are no brushes or brush holders and it could be too old to be able to obtain replacements from Dumore. One of the reasons why the 110v motor should be slipped into the bin.

Bob.

[simonl]

Thanks so much Bob! I assumed it wasn't the nice painted one, although it would be a shame if you accidently got them mixed them up! :D

WRT the motor, you are probably right. It probably does need to go to god, I just hate to see things thrown out especially good quality old things.
Me being the eternal optimist, I have emailed Dumore to see if they still sell parts such as brushes and brush holders for the motors. They will probably want a serial No. etc but it's a start.

Simon

[Anorak Bob]

Hi Simon,

I bought the "better" grinder from eBay seller Tissuescars about 9 years ago. It had been used at a place called Bell Engineering in Sydney? for one particular job. Tissuescars had a few of them for sale at the time. Mine was full of grinding dust slurry necessitating the replacement of the internal oil retention felts and wicks along with the bearings. I tried to purchase the felts and a few other parts from W. Sopko, the Dumore agents at the time - http://www.wmsopko.com/ . It all became too hard and I ended up buying the parts from Electric Tool Service who could not have been more helpful. Here is part of our email exchange which gives you some indication of pricing. This was pre Shipito and I had the parts sent to my brother.

I will provide you with a photo of the motor nameplate.

BT

Hi Bob,

Here are the prices for the items that you listed.
The part numbers that you referenced are the same for
your model 8365.

779-0004 oil wick @12.72 each
R646-0009 oil tube @$2.55 each
487-0014 1/8" collet chuck @$37.18 each
757-0008 dust thrower @$16.26 each
729-0035 spacer @$10.24 each

We can drop ship to New Jersey directly fom Dumore
VIA UPS.
The residential shipping charge is $10.57.
Prices are in U.S. Funds, and we accept all major
credit cards.

Regards,
Larry

[email protected]





([email protected])

[simonl]

Hi Bob,

Thanks for that. I had googled "Dumore motor parts" and W. Sopko was one of the many hits including a mention in a thread in another metalworking forum. I have also downloaded an owners manual for the 44 direct from Dumore. It has the exploded parts view. My experience with U.S. suppliers has been second to none and often leaves the customer service in Aus very much wanting.

I am confident that my Hitachi trimmer router (520W @ 30,000 rpm) will be a nice comfortable fit and work well with a speed controller attached to any TP grinder. However, the Hitachi green plastic will not look anywhere as nice as the original motor. :cool:

I'll have a gander at The Electric Toll Co.

Cheers,

Simon

[KBs PensNmore]

Simon, all you need to do is rough the plastic up a bit and it can then be painted black or what ever colour you want, as you can get paints to go on plastic.:D Looking forward to WIP report.
Kryn

[Anorak Bob]

348789

[simonl]

Thanks Bob, I appreciate your time you are putting into this.

I have shot off a few emails quoting the serial number to see if parts are available. Interestingly, a google search of electric tool co. showed no results and when I copied and pasted the email address you gave me into an email, it bounced back saying it could not deliver it. Sadly, they may no longer exist. Perhaps they have gone the way of the Doddo along with many a US firm?

Laid up with man flue ATM. I thught it was just a hang over after downing a bottle of port and a bottle of muskat with my sister. At least now I get (some) sympathy from the rest of the household!

Cheers,

Simon

[simonl]

Overnight I received a couple of emails, one from Sopko, one from Dumore. They both state they still sell parts for the motor. Interestingly, I quoted the serial number in both emails and the reply from Sopko was that the number, 3866 was not correct and that all serial numbers are 4 digits starting with "8"

I sent them the photo you posted. Perhaps the 3 is in fact an 8 but difficult to pick up due to the age of the motor. We shall see what happens.

Simon

[KBs PensNmore]

Hi Bob, would it be at all possible to paint the stone size, gearing and speed details and when dry, rub it with a bit of emery tape so that it can be read easily. PLEASE. :2tsup:
Also do you have the sizes of the pulleys, please, as it would make life a bit easier, rather than re-inventing the TPG:D.
Kryn

[simonl]

Hi Bob, would it be at all possible to paint the stone size, gearing and speed details and when dry, rub it with a bit of emery tape so that it can be read easily. PLEASE. :2tsup:
Also do you have the sizes of the pulleys, please, as it would make life a bit easier, rather than re-inventing the TPG:D.
Kryn

Kryn,

I'm feeling crap ATM with man flue so I'm bored out of my brian. Been watching youtube videos on the TV. Anyway, I downloaded the 44 manual which gives the speeds and the pulley combinations to achieve those speeds. Page 8
http://igor.chudov.com/manuals/Dumore-Series-44-Tool-Post-Toolpost-Grinder-Manual.pdf

Working with the ratios and since No.1 pulley is the smallest and No.5 the biggest, if you pluck a figure of 1.000" for pulley No.1 then pulley No.5 much be 2.961" from here you can work out the rest...

Pulley No. Size

1 1.000"
2 1.389"
3 1.834"
4 2.234"
5 2.961"

Of course if you find pulley No.5 a little big at nearly 3" then just readjust the ratios. You can either start from the smallest and work up to the biggest of start from what you want your biggest to be and work back to the smallest.

Cheers,

Simon

[Anorak Bob]

Seen this? http://www.woodworkforums.com/showthread.php?t=139799&p=1361997#post1361997

[KBs PensNmore]

Thanks Simon and Bob, some very handy information in that lot. Thanks again Gents:2tsup: Now to find the bits to make one, it should be better than using the Dremel.:D
Kryn

[simonl]

Hi Bob, Kryn.

I have had some responses to my emails. From Sopko I got this:

Thank you for the picture. Like they say a picture is worth a million words!

I advise you to NOT buy this. The “Tool Maker” was made in the 1940’s. No replacement parts are available.

I would shop around for another 44 and email me a pic

Thanks for considering to consult with me. I feel like I saved you some money and future headaches.

And then from Dumore themselves I got this:

Part number and pricing are as follows:

Carbon brushes R457-0622 $20.18 each in stock
Brush holders 451-0056 $451-0056 in stock

I can take your order direct with a credit card. Our minimum order requirement is $250.00. If not met there will be a $20.00 small order fee applied to your order.

Contact me directly when ready to place your order.


Go figure! now I'm not sure who to believe. I sent both people the photo of the motor, one says parts not available yet Dumore says they are. One would think that the original manufacturer would know what they were talking about?

What are your thoughts Bob?

Simon

[Anorak Bob]

Simon,

My advice is to waste no more time and effort on this until you have the grinder.

If the condition of the motor internals is indicative of the condition of the all important spindle then all you will be left with is basically a casting. I tried to photograph the interior of the motor but some further dismantling would be required to provide adequate photos.

It may well be that when you inspect the grinder, you too may consider it fit only for the Sulo bin.

Bob.

[Anorak Bob]

For those hell bent on ruining their lathes, here are a couple of scanned DIY grinder projects for inspiration.

[Burner]

Bob, you seem really concerned about that bit of dust from dressing a wheel. I hope your area where you keep your lathe is well sealed from dust that blows around on a hot windy day. I understand your concerns for getting grit into places it shouldn't be, but you do need to use the lathe, or else why have it? Have you tried using a dust extractor or vacuum to collect the dust as you dress the wheel?

When I was much younger we needed to reduce the size of a hardened pin by about 0.5mm so I wanted a TPG. I took an old 8" bench grinder that had the motor burnt out, removed 1 wheel and the gaurd and fitted a pulley. I then mounted it to a bit of old plate and fitted an old washing machine motor with a larger pulley to drive the grinder. I fitted this contraption to the back side of the cross slide on my old capstan lathe and used it to grind down the shaft. The surface finish was ordinary, probably because of the unbalanced wheel and type of wheel, but it worked. Desperate times call for desperate measures. I wish I had some pics of it, then you would all know how rough I am!!

[simonl]

Hi Bob,

I had been meaning to respond to your last post, reading Burners has prompted me to pull my finger out.

Hi Burner, there is no doubt that Bob is not Robinson Crusoe when it comes to concerns of using a TPG. A video I wated from Tubal Cain on TPG echoed the same concerns, stating that many people would not let you anywhere near their lathes with such a beast! While I wouldn't disagree with Bob, (I have learnt an awful lot from him) when it comes to opinions, I like to have the same experience that others have had that they used to form that opinion. In short, I need to experience things for myself wherever possible.

So, I still want one! :U

Bob, What would I owe you to send that grinder my way?

Simon

[Anorak Bob]

Bob, you seem really concerned about that bit of dust from dressing a wheel. I hope your area where you keep your lathe is well sealed from dust that blows around on a hot windy day. I understand your concerns for getting grit into places it shouldn't be, but you do need to use the lathe, or else why have it? Have you tried using a dust extractor or vacuum to collect the dust as you dress the wheel?

When I was much younger we needed to reduce the size of a hardened pin by about 0.5mm so I wanted a TPG. I took an old 8" bench grinder that had the motor burnt out, removed 1 wheel and the gaurd and fitted a pulley. I then mounted it to a bit of old plate and fitted an old washing machine motor with a larger pulley to drive the grinder. I fitted this contraption to the back side of the cross slide on my old capstan lathe and used it to grind down the shaft. The surface finish was ordinary, probably because of the unbalanced wheel and type of wheel, but it worked. Desperate times call for desperate measures. I wish I had some pics of it, then you would all know how rough I am!!

Burner,

As surprising as it may be to you, I do use my lathe. I just don't want it covered in grinding wheel grit and if others are happy to use TPGs, good on them.

Bob.

[Anorak Bob]

Simon,

If you haven't already got one, obtain a small mounted grinding wheel and stick it in your chuck and then dress the wheel with a diamond dresser. A quick way of determining whether you can contend with the mess.

As far as the Dumore goes I could post it off to you tomorrow without the rooted motor in a Parcel Post bag. And there is no cost.

Bob.

[simonl]

Hi Bob,

Yes I have diamond dresser I use the t&c grinder and well as the sg. It's unbelieveable the amount of dust created! Admittadly I have never done it with a vacuum cleaner close by.

OK, I will give up on the idea of resurrecting the motor! Happy to recieve the remnants though. Not sure why the postage is free? I'll PM you my address.

Cheers & Thanks

Simon

[PDW]

Bob, you seem really concerned about that bit of dust from dressing a wheel. I hope your area where you keep your lathe is well sealed from dust that blows around on a hot windy day. I understand your concerns for getting grit into places it shouldn't be, but you do need to use the lathe, or else why have it?

I use my lathes a *lot*. Especially the Chipmaster. There is no way on earth I'd allow a toolpost grinder anywhere near that machine. It can hold tolerances at the 0.0002" to 0.0005" over 6" even though it's 40+ years old. A few years with a toolpost grinder and you could knock a significant figure off of that.

Other people can do whatever - I prefer not to have grinding equipment even in the same room as my lathe. The only time I'd install one was on a machine I didn't care about and yeah, I know sometimes you do what you have to do, but you rarely really have to do some things with a bit more planning.

PDW

[Burner]

I didn't mean to cause any offence to anyone, particularly Bob as I value his significant input on this forum. I respect everyones choice to treat their machines as they see fit. I never meant to imply that you gentleman don't use your lathes. I see my post was a bit blunt. Please accept my apologies.

My post reflected the ongoing internal struggle I often face myself. I don't want to cause any wear or damage to my machines, but I have jobs that need doing. I often have to tell myself that I need to use the machine or else why do I have it. I would like to have exactly the tool or machine for every job and I have an awful lot of stuff, but not always the right thing. This is not only with my workshop but also farm machines.

I am not the guy who can have a hot car in the shed to cruise in, to me it has to perform to its potential, hence I have done some rallying. I have old tractors, not painted and polished but in their working clothes and they still getting occasional use.

PDW, I have been milking cows for 20 years and that happens twice a day, 7 days a week, 365 or 366 days a year. Cows need milking, feeding, moving and milk needs cooling and all the other seeding and harvesting etc needs to happen when the weather and everything else is spot on. Stuff generally only breaks when you use it and often that is when all the suppliers are closed or the budget won't allow a proper fix. I have had to do a lot of dodgy stuff in a short time and compromise my ideals. It all depends on your circumstances how rarely these things happen.

My best lathe (a VDF Boehringer) in its former life was used with ceramic tools to re shape hardened steel tube forming rollers. It did this and other work for about 30 years. It had suitable covers and gaurds to protect the ways fron the swarf etc.. It has some wear on the bed, about what a 40+ year old industrial lathe that is used daily gets. It has rarely caused me any issues in regard to accuracy. Most of the pieces that I need really precise get hardened and then ground on the cylindrical grinder. My point is that machines can often take more "abuse" than we think they can, but I understand if people do not want to take that risk. Sometimes the machines can't take it and they are very sad days!!

I hope this explains about me and my posts better.

Craig

[PDW]

I hope this explains about me and my posts better.

Craig

I didn't take any offence and I doubt anyone else did either. That's why I said that sometimes you do what you have to. I spent a lot of time working on deep ocean ships where we might be gone for up to 3 months without touching port. We had a lathe, Arboga mill/drill and welding gear. After the first voyage I learnt to take my own metrology gear and lathe tooling plus my preferred selection of welding rods.

The lathe wasn't much as it had been abused for years but it was better than none.

If I had absolutely no other choice I'd use a TPG, but it'd have to be truly desperate measures.

OTOH I'm wondering how I ever managed to survive this long without my small surface grinder. Now I want a cylindrical grinder......

PDW

[Hunch]

Overnight I received a couple of emails, one from Sopko, one from Dumore. They both state they still sell parts for the motor. Interestingly, I quoted the serial number in both emails and the reply from Sopko was that the number, 3866 was not correct and that all serial numbers are 4 digits starting with "8"

I sent them the photo you posted. Perhaps the 3 is in fact an 8 but difficult to pick up due to the age of the motor. We shall see what happens.

Simon

Had a look at the mate's one, it's 220v and the serial # there starts with an A, looks like Bob's starts with a B to me....so I'd have to wonder what Sopko are talking about!

His seems to have lost a few bits over the years, but all the pulleys appear there and wasn't game to switch it on :oo:. Dunno what depression era dollars work out to now, probably 2k-ish possibly?

[simonl]

Hi Hunch,

That's a similar series grinder to Bob's one that's getting the motor binned. The "Tool Maker" was made in the 1940's according to Bill Sopko, who replied to my email. Interestingly, it apparears that Bob's advice to forget about the motor was sound. I re-emailed Dumore to confirm that they had parts for that motor (this was prior to deciding to throw it out) as I explained that Sopko claimed no more parts were available. Their response was Oops, sorry, they are correct, no parts are available!

So, in short tell your mate to look after that TP grinder since no parts are available!

Simon

[.RC.]

I wonder if I could fit a tool post grinder to the 10EE?


:wink::wink:

[Oldneweng]

I wonder if I could fit a tool post grinder to the 10EE?


:wink::wink:

You could keep an eye out for a Pink Light Red one. :rolleyes:

[simonl]

I wonder if I could fit a tool post grinder to the 10EE?


:wink::wink:

Only if it's a half decent lathe...:rolleyes:

[QC Inspector]

Before you guys "bin" the old motor consider saving the motors case. Pull the windings out and an adapter can be made fit inside to hold the router motor. If the router you have is a cylindrical / barrel type then the adapter is just a big bushing that can be made of aluminium, plastic or even hardwood. Using the old motor case removes the need to make a mount to fit the rest of the TPG.

Pete

[simonl]

Before you guys "bin" the old motor consider saving the motors case. Pull the windings out and an adapter can be made fit inside to hold the router motor. If the router you have is a cylindrical / barrel type then the adapter is just a big bushing that can be made of aluminium, plastic or even hardwood. Using the old motor case removes the need to make a mount to fit the rest of the TPG.

Pete

Hi Pete,

Thanks for the suggestion. I read your post and had a really good think about it but the motor I'm thinking of using is oval not round so it would most likely add further complications to the project. I very reluctantly told Bob to bin the motor.

Anyway, I recieved the parts so generously given to me bu Bob and spent the last couple of mornings disassembling and cleaning. Boy I love good quality old stuff. Such a pleasure to play with!

After a few hourse of scrubbing and US cleaning, I gotta say, most things look pretty bloody good. The spindle has a few rust blemishes. I carefully removed some but figured I may do more harm than good if I go too far since it's designed to spin at close to 40K. The engineering felt and felt wicks that lubricate the bearings will be replaced (eventhough they didn't seem too bad from something built in 1940's) The bearings are most probably shagged too although I have cleaned them and may see how they go. They are expensive little buggars!

Anyway, for anyone interested, here are a few pics of all the parts disassembled and of the trimmer router I plan to use to power it. I can't believe how well the motor mount actually fits the router, obviosly I will need to come up with a proper mounting harness for it. Also as luck would have it, the router spins the wrong way. It would produce sparks directed upwards. However, every cloud has a silver lining and a quick peek inside reveals that it's pretty easy to reverse one of the fields and have it run reverse. This would also change the ventillation direction meaning intaking "clean" air from the pulley end and blowing it out the rear where the grinding is happening. I may still come unstuck this idea since I have read that while these universal motors can run in either direction, they are designed to run one particular way. Time will tell.

349910349913349911349912

Simon

[rusel]

You could make one like this bloke did....Very impressive
https://www.youtube.com/watch?v=sFrVdoOhu1Q

Russell

[simonl]

Yep, I have seen that video. Very impressive That won't be happening anytime soon in my shed!

I know my limitations.

Simon

[Anorak Bob]

That was a prompt dissection Simon. http://d1r5wj36adg1sk.cloudfront.net/images/smilies/happy/biggrin.gif

How is bearing preload achieved ? And can you slow the trimmer motor down?

I purchased new wick assemblies and the felt sleeve. One end of the wick is tucked under the sleeve and the wick is then wound around a felt rod. The rod touches the narrow section of the taper on the spindle. The sleeve is charged with oil and it makes its way into the wicks and rod and onto the spindle where centrifugal action flings it off the wide end of the taper in a mist. In my hunt for appropriate oil, the Dumore oil being thin and not readily available, I contacted Mobil and it was suggested that fork oil would be an acceptable alternative. I will photograph the container if you are interested.

I thought the bearings were a bit rough. It will be interesting to find out if they run smoothly after a clean. The New Departure bearings in mine were rooted. Hopefully you can find a cheaper alternative to the Barden replacements I used.

I might have some photos of the felt and wick setup. From memory I had to slit the rod and insert the wick, a bit like threading a needle.

Bob.

[DSEL74]

Don't know if this is any help
http://www.opensourcemachinetools.org/archive-manuals/Grinder.pdf

[simonl]

Hi Bob,

Yep I didn't waste any time getting it apart and cleaning. I really enjoy that sort of thing. Of course that's no indication of how quick the project will be finished! The yanks do make some nice stuff. That casting, as small as it is, is quite intricate when you look closely.

The trimmer as it is has no means of variable speed. It must be over 30 years old. However I have a 1000W (rated) speed controller for such motors and may look at using that although I can still see benifit in a few pulley combinations rather than totally relying of electronic speed control.

The preload is achieved with a small screw in assembly that screws into the pulley side of the casting, srewing it out pushes a preload spring up against the outer race of the bearing. Since the spindle "floats", the other bearing gets equal preload as it gets forced up against the casting at the other end. Once the preload has been set, a small brass set screw locks the preload screw.

Hope the pics make more sense. The last pic shows the shiny part where the felt wick makes contact on the spindle.

WRT the felt tube and wick. I will replace these, being a tight wad I am thinking of using some engineering felt I already have although I may just buy some from Dumore. I will need some advice with placement since the wicks pretty much fell apart and it was very difficult to see exactly how they sat. As for the felt tube, I can't for the life of me remember now whether the join faced upwards to the filler plug or face down. I'm thinking it faced down so that when replacing the oil it does not fall straight onto the spindle?

I'm thinking I may be optimistic with these bearings. However, I am confident that new bearings will see this spindle back to near new. The bearings are a 7200 series angular contact bearing in a P4 precision. Yet to find any decent one for under about $100 each. I can't see any point in putting in "regular" bearings. It would seem a waste.

350019350021350022350023350024

Cheers,
Simon

[Anorak Bob]

Simon,

It might be prudent to reassemble the grinder and check that the spindle runs true before you throw money at fresh beaings.

Attached is a 2008 pricelist. Whilst I imagine the pricing has increased during the intervening years, it should give you some idea of the cost of some of the bits and pieces you might need if the spindle proves to be satisfactory.

Bob

[simonl]

Don't know if this is any help
http://www.opensourcemachinetools.org/archive-manuals/Grinder.pdf

Thanks! I'll get some more ideas from this.

Simon

[simonl]

Simon,

It might be prudent to reassemble the grinder and check that the spindle runs true before you throw money at fresh beaings.

Attached is a 2008 pricelist. Whilst I imagine the pricing has increased during the intervening years, it should give you some idea of the cost of some of the bits and pieces you might need if the spindle proves to be satisfactory.

Bob

Thanks Bob,

I have been mucking around with test fitting on the lathe etc. It soon became apparent that when at centre height, there is a finite limit on the pulley size that will fit on the spindle and not fowl the compound. The trimmer runs at 30K which in some ways presents some challenges. It means I cannot change speeds purely electronically if I want useable operating speeds from 6,000 to 38500 rpm. The maximum size pulley I can fit on the spindle is about 60mm diameter, probably 50mm or 2" would be more realistic. So I was thinking 3 pulley sizes, 25mm, 32mm & 52mm and electronic speed control from 15K to 30K will probably get me by.

I'll re-assemble the spindle and report back on runout….

Cheers,

Simon

[simonl]

Oh BTW WRT the bearings. Here's exactly what I need and at a "reasonable" price:
http://www.ebay.com.au/itm/B7200C-T-P4S-UL-10mm-id-x-30mm-x-9mm-wide-PRECISION-ANGULAR-CONTACT-BEARINGS-FAG-/361254958269?pt=LH_DefaultDomain_15&hash=item541c7934bd

Question is, I don't think the seller really knows what type of bearing he is selling. Photos tell a different story to the description! I have left a question for the seller but he is yet to reply! :no: here is no way they can be 7200 precision P4 for that price!

Simon

[simonl]

Ok. I will have to do so further testing but according to the quick and dirty indicator setup I did, the spindle has less the half a thou runout. In fact it's difficult to see the 0.001" indicator actually move. I'd have a guess and say there is 0.3 thou runout? I'll know further when I attach the 2um DTI to it but I think it's safe to say it's OK. I also gave the bearings a squirt with oil just to "smooth" them out a bit for the test and they too don't feel that bad.

I think I'll order the felt wicks and tube.

Been looking in my scrap bin for some material to make the pulleys with, What do people think about pulleys made from Acetyl or should I stick with aluminium? My thinking is that acetyl is yet lighter again the aluminium which would further reduce any potential vibrations should there be any variance in balance of the pulleys.

Simon

[Anorak Bob]

All but the largest pulley Dumore supplied with my* 44 are steel, the former being aluminium. They are crowned, from memory with a tighter radius than the 1/8" in a 1' Michael mentions in his J & S thread.

Bob

* actually yours, the pulleys were one of the reasons I bought the boat anchor. They and the rotor proved to be the only things of worth to me.

[simonl]

Thanks Bob.

I'm yet to work out how to crown the pulleys. I was under the impression Michael crowned his pulleys "free hand" and did a good job. I wouldn't think I would be as good at it. Looks like I need to made another ball turner, one for crowning pulleys. How big will that end up being! :doh:

Simon

[Machtool]

Oh BTW WRT the bearings. Here's exactly what I need and at a "reasonable" price:
http://www.ebay.com.au/itm/B7200C-T-P4S-UL-10mm-id-x-30mm-x-9mm-wide-PRECISION-ANGULAR-CONTACT-BEARINGS-FAG-/361254958269?pt=LH_DefaultDomain_15&hash=item541c7934bd

If that bearing really has the part number 7304B.TVP.UO. That's not the bearing you want. Its only a commercial grade. And a 40 deg contact angle. That's the B in the Code. The TVP is just a polyamide cage. UO is universal fit. Best grade they come in is a P5, but that's missing. It would have P5 after the "UO". That makes it a P6 grade. Normal commercial.

Plus its the wrong size if you really need a 7200.

Regards Phil.

[Anorak Bob]

This was marked on the box my replacements came in. FAG / Barden Aerospace 200HC B7200C.T.P4S.UL. Good for 85,000 RPM with oil lubrication . See page 25 in this link.

- http://www.bscindia.com/catalogue/FAGPrecBrgsCat.pdf

The need for speed comes at a price though!

BT

[Machtool]

Simon.

I rang one of my bearing suppliers. I've found a pair of Fafnir 2MM200W1DUL. Same / same only a different number. $102 for the pair.

Ex stock Melbourne.

Regards Phil.

[simonl]

Hi Phil Hi Bob, Thanks for your input and advice. I ended up getting a reply from the seller of that bearing on ebay. He confirms that it is definitely an FAG B7200C.T.P4S.UL (similar to yours Bob except yours has ceramic balls I think) and states that its old new stock from a customer that went broke. One only though and if I want anymore they will be $165 each. Not sure if I did the right thing but I bought it, that was before I saw Phils offer of $102 for a pair! :doh: That's a bloody good deal. I have searched the web high and low and the best price I could find was about $100 each + delivery. Phil, if this bearing turns out to be legitimate, can you buy them single or am I now stuck with a spare? Yes, I am a tight wad! Cheers, Simon

[nearnexus]

The trimmer runs at 30K which in some ways presents some challenges. It means I cannot change speeds purely electronically if I want useable operating speeds from 6,000 to 38500 rpm.
Cheers,

Simon

Hi Simon. Why are you looking to drive the TPG spindle to 38,500 RPM?

I have a C0 Waldown TPG, and as the safe surface speed of a bonded grind stone is approximately 32 metres/second, that equates to a quill speed of 24,000 RPM for a 19 mm internal abrasive.

So 24K is a hard as you will ever need to drive it - for small diameter stones.

Incidentally, the Waldown uses hi speed magneto bearings (open cage ball race) in both quills.

I had to replace one and bought a full set for both quills - $25 each from CBC Bearings.

Rob

[simonl]

Hi Simon. Why are you looking to drive the TPG spindle to 38,500 RPM?

I have a C0 Waldown TPG, and as the safe surface speed of a bonded grind stone is approximately 32 metres/second, that equates to a quill speed of 24,000 RPM for a 19 mm internal abrasive.

So 24K is a hard as you will ever need to drive it - for small diameter stones.

Incidentally, the Waldown uses hi speed magneto bearings (open cage ball race) in both quills.

I had to replace one and bought a full set for both quills - $25 each from CBC Bearings.

Rob

Hi Rob,

That's a fair point. I have never really used a TP grinder for internal grinding. I just had the idea of returning the dumore back to it's original capacity, which is running a 1/8" grinding wheel at 38K. Will I ever need to internally grind a bore that size? probably not but hey why not have the option! I dare say any future use of this unit will be mostly external grinding needing little more than maybe 6000 rpm.

How come you can get $25 bearings for your grinder? :cool:

BTW, I did some more testing of the spindle with a 2um dti. It tells a different story. The runout seems to be about 0.01mm but totally random in location (high spot changes from one turn to the next). I dare say this points to the bearings being shagged afterall.

Simon

[nearnexus]

Hi Rob,

That's a fair point. I have never really used a TP grinder for internal grinding. I just had the idea of returning the dumore back to it's original capacity, which is running a 1/8" grinding wheel at 38K.

How come you can get $25 bearings for your grinder? :cool:

Simon


I wondered if you were trying to run diamond burrs in it - that's the only reason for such a speed.

I get my bearings cheap because I am cheap. He he. No not really. These are a standard high quality magneto bearing (NSK) and don't cost an arm and a leg.

My TPG doesn't have a collet chuck, and can't drive burrs. But then again, I can't see when I would ever need to do that.

Your bearing runout could also be due to incorrect adjustment.

Rob

[simonl]

I wondered if you were trying to run diamond burrs in it - that's the only reason for such a speed.

Rob

Hell no nothing like that. My machining requirements (and skills) are fairly basic compared to many on here. I seem to be consistantly 3-4 years behind everyone else on here. What's new to me, has usually been discussed here some years back. :U

Simon

[Anorak Bob]

Simon,

Can you check the trueness of the spindle between centres? I never looked at the condition of its centre holes and if they are knackered I don't know how they could be made good enough to provide the accuracy required for checking runout. It would be pointless throwing money at any bearings if the spindle is bent.

I do agree, Rob's NSKs are appealing. The internal grinding spindle on the Hercus No. 1 does not have hundred dollar bearings fitted neither does the main spindle.

Apart from the grit, my other issue with the Dumore was motor vibration. Having bought the thing second hand and never experiencing the live working of a new Dumore, it's hard to know what is normal. Alan "C-47" has a Waldown ( a CO I think ). It too vibrated but to a lesser extent than my 44.

If I did have reason to use a grinder on the lathe and let's say it was the Dumore I'd be tempted to ditch the motor and rig up an external drive along the lines of Schaublin's. Whilst the photos show a milling spindle, the grinding spindle setup is the same.

BT

350225 350224 350223 350222

[nearnexus]

Simon,


Apart from the grit, my other issue with the Dumore was motor vibration. Having bought the thing second hand and never experiencing the live working of a new Dumore, it's hard to know what is normal. Alan "C-47" has a Waldown ( a CO I think ). It too vibrated but to a lesser extent than my 44.

BT



I don't have any motor vibration issues at all with my C0 Waldown. It's many years old, but absolutely silky smooth.

The motor does scream very loudly, but the bearings are all good and lubed - just the nature of the beast.

The only issue I have is that the internal quill spits oil at me (severely) at the drive belt end.

I made up a replacement felt seal for it after the last time I used it (recently to true my scroll chuck jaws), cause I looked like Mel Gibson from Braveheart after with half my face and neck white and the other half black with oil. Had to use copious quantities of hand degreaser to get it off. Not the first time it's got me.

I haven't tested ithe new seal's effectiveness yet.

Interestingly, I don't see these felt seals in the Brobo spares listing, so I guess they are made from unobtainium. However, very simple to make with a couple of knock up wad punches.

These grinders are great for restoring chucks - my 10 year old old Chinese scroll chuck internal jaws came back to 0.02 - 0.025mm repeatable across a wide range of work sizes after this treatment.

Very handy item.

Rob

[simonl]

These grinders are great for restoring chucks - my 10 year old old Chinese scroll chuck internal jaws came back to 0.02 - 0.025mm repeatable across a wide range of work sizes after this treatment.

Very handy item.

Rob

I think I saw that on your you tube channel.

Simon

[simonl]

Simon,

Can you check the trueness of the spindle between centres? I never looked at the condition of its centre holes and if they are knackered I don't know how they could be made good enough to provide the accuracy required for checking runout. It would be pointless throwing money at any bearings if the spindle is bent.

I do agree, Rob's NSKs are appealing. The internal grinding spindle on the Hercus No. 1 does not have hundred dollar bearings fitted neither does the main spindle.

Apart from the grit, my other issue with the Dumore was motor vibration. Having bought the thing second hand and never experiencing the live working of a new Dumore, it's hard to know what is normal. Alan "C-47" has a Waldown ( a CO I think ). It too vibrated but to a lesser extent than my 44.

If I did have reason to use a grinder on the lathe and let's say it was the Dumore I'd be tempted to ditch the motor and rig up an external drive along the lines of Schaublin's. Whilst the photos show a milling spindle, the grinding spindle setup is the same.

BT

350225 350224 350223 350222


Hi Bob,
Testing B/T centres had crossed my mind but I'm yet to do it. Not sure how reliable the centre holes are but worth a try. Other option is to rest the bearing journals on V blocks and check that way. Work prevents me from anything right now but will attempt to get a final picture of the spindle on the weekend.

Remotely mounting the motor looks bloody complicated for something that may only get used 3 -4 times a year. There is a strong case for a cylindrical grinder isn't there? :U
Simon

[simonl]

Morning all,

bit of a rush this morning but I had a look at the runout with the spindle bearing mounts resting on V blocks. Runout is around 5um so about 2 tenths. I'm happy with that and happy to go ahead with the project. Didn't bother to use the centres as they look a bit shabby.

Simon

[Ueee]

Hi Simon,
When i crown wheels i set the compound to 1 deg and taper the wheel off each edge for about 2/5 of the width. Then you can blend the flat spot with a file/emery. 1 deg gives you about the 1/8" per foot, without measuring i think thats what my waldown would have. It has ally wheels but they are very light, with only a thin face and web connecting to the hub for the larger ones, i think the little (25mm) one is solid.

I have wondered if a water cooled cartridge spindle might be the way to go, but then even the cheap ones are not that cheap!

[simonl]

Thanks Ueee,

crowning the wheels has had me stumped. I was wondering whether a ramp up and down from the centre would "do the job" Using emery to "blend in" the ramp in the middle may just be the go. I was also thinking of cheating and just doing a flat pulley with 2-3mm lip on each side.

Bob, I need some help with the felt installation. I'm thinking the felt that rubs on the spindle starts in the threaded hole (with brass plug) at each end of the casting, passes through the where the two ends of the felt tube join and the curl around to make contact with the spindle. There is also some string attached to the felt wick, does this tuck under the felt tube (top of the casting) and act as the wicking for the lubricant from the felt tube to the spindle?

Simon

[Ueee]

If you use a flat pulley with lips the belt will jump or bounce from one side of the pulley to another and destroy itself in an alarmingly short time.
The 1deg taper and blend works very well, if you go with a more aggressive crown they tend to ruin the belts by stretching the middle of the belt and you and up with very little belt actually gripping the pulley.

[Michael G]

Just to add to Ewan's comments Simon, when I worked out the necessary crowning for the pulleys I made, (because I was not sure that I would fit the large one on the lathe), I worked out what the tangent angle would be if I wanted to do some trick stuff on the mill. Turned out the tangent angle was around 1 degree. If I'd crowned the pulley on the mill it would have been very similar too - the cutter would have removed around a third of the face and then I would have had to blend it.
The edges on my pulleys are only there to prevent the belt flipping off when things are not rotating - other than that I expect the belt will ride on the top of the crown, even if it is only a fraction of a mm.

Michael

[Stustoys]

Thank you gentlemen, I'd wondered for awhile why some pulleys have both flanges and crown.

Stuart

[nearnexus]

Thank you gentlemen, I'd wondered for awhile why some pulleys have both flanges and crown.

Stuart

On my C0 Waldown, only the motor pulleys are crowned. It is a two diameter stepped pulley.

The spindle pulleys are flat and have a flange each side.

Works well. The crowned motor pulley basically sets the belt position.

Rob

[simonl]

Ueee, Michael & Rob, Thanks for the info. So a mathematical approximation to a crown will satisfy the belt then. 1 deg sloped either side from the middle and then nick the top off to produce a symmetrical trapezoid? Simon

[Michael G]

Rounded - a corner may cut the belt.

Michael

[Ueee]

Yeah round it over the best you can. I have been making rubber wheels so it is pretty easy to do, in ally it may take a bit more time.

[nearnexus]

Ueee, So a mathematical approximation to a crown will satisfy the belt then. 1 deg sloped either side from the middle and then nick the top off to produce a symmetrical trapezoid? Simon

I had to sleeve and crown the largest pulley on the intermediate shaft for my old Schaublin 102.

It was in steel, and I did it by eye, free hand.

I just crowned it until it looked right (same as the rest), but you certainly don't need much to centre a belt.

I did it in small steps starting from each side (did both sides then moved up), worked towards centre (same principle as making a cone), then smoothed out the ridges in one freehand pass with a finishing cutter, and used a fine file and old belt sanding strips to finish it off.

I think I used a 35 degree profiling cutter, same as for making "V" pulleys.

Pretty easy job - came up great.

I practiced on a bit of scrap first, so maybe do that to get the depth/process right.

The pulley surface should be rounded, so I don't like your nip off the top idea,

Rob

[simonl]

Thanks Rob,

I see what you mean, I have been thinking a bit about it this morning. I have been trying to approach this from a mathematical POV. A height difference of 1/8" per foot equates to a segment of a circle with a radius of approx. 3750mm. Not sure how that helps me but it's a start. I'm trying to work out the DOC and angles required to approximate a circle of radius 3750 with 5 flat edges to approximate the crest. Then smooth out with emery.

I have just worked out the angle of the tangent from the edge of each side to be 2.67 deg. That's a fair bit off the 1 deg that you guys estimated. I'll have another look…...

Simon

[nearnexus]

Thanks Rob,

I have just worked out the angle of the tangent from the edge of each side to be 2.67 deg. That's a fair bit off the 1 deg that you guys estimated. I'll have another look…...

Simon

Hi Simon.

I never subscribed to the one degree theory. I don't know where that came from.

Certainly the curvature on my C0 Waldown is greater per width, than my old Schaublin.

Modern thin section drive belts can wrap around any sized curvature really.

They are not like the old leather and stiff belts which will ride up on the crown.

The belts on my C0 are actually made of a type of woven fabric (original) and as flexible as a sock :).

So I wouldn't get too hung up on the degree of curvature being x or y if you use a modern polyester or specialised belt (within sensible limitations).

Rob

[simonl]

Hi Simon.

I never subscribed to the one degree theory. I don't know where that came from.

Certainly the curvature on my C0 Waldown is greater per width, than my old Schaublin.

Modern thin section drive belts can wrap around any sized curvature really.

They are not like the old leather and stiff belts which will ride up on the crown.

The belts on my C0 are actually made of a type of woven fabric (original) and as flexible as a sock :).

So I wouldn't get too hung up on the degree of curvature being x or y if you use a modern polyester or specialised belt (within sensible limitations).

Rob

Thanks Rob. I do think things a bit too much sometimes but one of the parts I like about this hobby is the mathematics which I enjoy playing with.

Cheers,

Simon

[simonl]

I just took the time to have a good look at the flat belt pulleys on my T&C grinder. Looks like im over complicating the whole thing! These pulleys only have two surfaces, ramped up to the centre and then down. The high spot in the middled is rounded but they are essentially flat with the high spot being about 1.5mm higher tgan the sides. These pulleys are about 1" wide. I measured the angle at roughly 3.5 deg. Think ill just copy these.

Edit: Was having trouble attaching pics from my mobile. Here are the pulleys on the t&c grinder:

350574350575

[Anorak Bob]

.......There is also some string attached to the felt wick, does this tuck under the felt tube (top of the casting) and act as the wicking for the lubricant from the felt tube to the spindle?

Simon

Yes.

[KBs PensNmore]

I just took the time to have a good look at the flat belt pulleys on my T&C grinder. Looks like im over complicating the whole thing! These pulleys only have two surfaces, ramped up to the centre and then down. The high spot in the middled is rounded but they are essentially flat with the high spot being about 1.5mm higher tgan the sides. These pulleys are about 1" wide. I measured the angle at roughly 3.5 deg. Think ill just copy these.

Edit: Was having trouble attaching pics from my mobile. Here are the pulleys on the t&c grinder:

350574350575

Nice little tool in the first photo, you've got there Simon. What brand is it, and where did you acquire it from, please?
Kryn

[simonl]

Thanks Bob.

Hi Kryn. Its a starrett bevel gauge. I inherited it from my Dad. Do not when or where he got it. It has a name on it A. G. Flood but thats not my dad. http://images.tapatalk-cdn.com/15/06/21/c40972fe01af90ae1a77b9fbbdec11cc.jpghttp://images.tapatalk-cdn.com/15/06/21/d501795a65e77033341414d0fdda4ccb.jpg

[simonl]

That was a prompt dissection Simon. http://d1r5wj36adg1sk.cloudfront.net/images/smilies/happy/biggrin.gif

How is bearing preload achieved ? And can you slow the trimmer motor down?

I purchased new wick assemblies and the felt sleeve. One end of the wick is tucked under the sleeve and the wick is then wound around a felt rod. The rod touches the narrow section of the taper on the spindle. The sleeve is charged with oil and it makes its way into the wicks and rod and onto the spindle where centrifugal action flings it off the wide end of the taper in a mist. In my hunt for appropriate oil, the Dumore oil being thin and not readily available, I contacted Mobil and it was suggested that fork oil would be an acceptable alternative. I will photograph the container if you are interested.

I thought the bearings were a bit rough. It will be interesting to find out if they run smoothly after a clean. The New Departure bearings in mine were rooted. Hopefully you can find a cheaper alternative to the Barden replacements I used.

I might have some photos of the felt and wick setup. From memory I had to slit the rod and insert the wick, a bit like threading a needle.

Bob.

Hi Bob,

I just re-read this post and it is now clear how the felt rod and wick is assembled. The actual wick looks like a heavy type of cotton. WRT the fork oil, do you mean fork oil as in for motorcycle forks?

Simon

[simonl]

Well I have just replaced the felt tube and lubrication wicks. I decided to make them myself. I had some engineering felt let over from another job so the felt tube was easy, just cut to the same dimensions as the old one. The felt wicks proved to be very, very fiddly but I wasn't about to let it beat me!

I started with a srip of felt and then wound cotton twin along it. Once the cotton twin is wound the entire length of the felt, a 2" tail is left. This tail tucks underneath the felt tube inside and wicks oil from the felt tube to the felt rod, which lightly rubs on the spindle.

Also recieved that bearing I bought from ebay. It's only one bearing but it was so cheap I couldn't ignore it! Now I need another one...

350653350651350654350652

Simon

[Michael G]

http://images.tapatalk-cdn.com/15/06/21/d501795a65e77033341414d0fdda4ccb.jpg

A Starrett 47 bevel gauge - still available today new but US$109 + shipping (amazon price)
Better hang on to that one Simon...

Michael

[Machtool]

Simon..

I got your message about finding another bearing. How is the pre-loading done on that spindle? Are there any springs involved? Spring preload would make it easy. And I could find a single universal at less than retail.

Did you take that bearing out of the wrapper for that picture, or was that as received?

Regards Phil.

[simonl]

Thanks For the further info Michael. I inherited a few little keepers like that from Dad. Stuff I would never think to buy but have come in so handy and it has sentimental value to me too. I'd never sell any of Dad's stuff, I'd more likely give it away here if I couldn't use it since I know it would go to a good home.

Hi Phil, thanks for the reply. The bearing came in a sealed plastic bag and it's cardboard box. I have since put it in a zip lock bag. The bearings are preloaded using a spring type arrangement that is adjusted my a threaded sleeve that can be screwed in or out of the main body to provide thrust adjustment onto the outer race. I'll duck out to get a pic.

Simon

[simonl]

Phil, first pic shows to the parts to the preloading system. Next pic shows how it screws into the barrel of the spindle casting. The bearing would obviously sit up next the the spring on the spindle.

350693350692

Cheers,

Simon

[Anorak Bob]

Determining preload might be tricky, any plans Simon?

Bob.

[KBs PensNmore]

Thanks Bob.

Hi Kryn. Its a starrett bevel gauge. I inherited it from my Dad. Do not when or where he got it. It has a name on it A. G. Flood but thats not my dad. http://images.tapatalk-cdn.com/15/06/21/c40972fe01af90ae1a77b9fbbdec11cc.jpghttp://images.tapatalk-cdn.com/15/06/21/d501795a65e77033341414d0fdda4ccb.jpg


Looks like a real handy tool. Funny how tools are accumulated like that, I've got several tools that have got other peoples names on them, I found a pair of cable cutters on a roof I was doing a job on once, several other tools were found on the road, beauty of riding a deadly treadly. I had a WB tension wrench 1/2" that my father found under the seat of a panel van that he'd bought.
Kryn

[simonl]

Determining preload might be tricky, any plans Simon?

Bob.

Yep. Trial and error. Start light, run and monitor the bearing temps and keep adjusting until they run warm but not hot and also look at the surface finish.

Well, that's my plan anyway. Reading your TPG thread I see you had to mess around a bit with preload too so was also guided by that too.

Edit: First I got to finish making these pulleys though!

Simon

[simonl]

Looks like a real handy tool. Funny how tools are accumulated like that, I've got several tools that have got other peoples names on them, I found a pair of cable cutters on a roof I was doing a job on once, several other tools were found on the road, beauty of riding a deadly treadly. I had a WB tension wrench 1/2" that my father found under the seat of a panel van that he'd bought.
Kryn

Yep, I also have some stuff accumulated from where I do not know!

Simon