Mandrel saver ?

[Pariss]

Hey Guys. Got my mandrel saver the other day from GPW and used it for the 1st time today. Now, the spindle of the mandrel goes about 30mm into the front of the saver, and the front of the saver butts up against the bush inserted into the blank, .....Right ??. Well, if I turn the dead center adjusting wheel to apply enough pressure to stop the square blank from spinning on the mandrel when turning, I get a loud grinding, vibrating sound coming from the saver. I have to back off the pressure to eliminate this noise, BUT, then the blank spins on the mandrel every time I put a chisel to it. Have I got a dodgy mandrel saver with a dicky bearing, or is this vibrating / grinding noise normal from these things ??. :oo::?

[gawdelpus]

Sounds like a bad bearing :( , these things just use a standard sealed bearing ,not a thrust bearing ,but if its noisy under pressure that is not good at all . Are your ends squared up properly on your blank as if not it could push to one side and bind , I made my own in the end using a clutch throwout bearing from a mini I believe :) cheers ~ John

[Ironwood]

Hey Pariss the mandrel shaft isnt bottoming out in mandrel saver is it ? I use spare bushes as spacers to save having to adjust the shaft in and out for different length pen barrels.
Mine is a homemade one so may differ from yours.

[Pariss]

Sounds like a bad bearing :( , these things just use a standard sealed bearing ,not a thrust bearing ,but if its noisy under pressure that is not good at all . Are your ends squared up properly on your blank as if not it could push to one side and bind , I made my own in the end using a clutch throwout bearing from a mini I believe :) cheers ~ John

Thanks John, yes, the ends are dead square. I only bought the thing out of curiosity, to see if it made any real difference, but think I will just sick with my 60deg cone dead centre, as it runs silent, and has never put a bow in the mandrel. :)

[cookie48]

Got one and never had problems with it. Sounds like you got one made on a Friday arvo.

[Pariss]

Got one and never had problems with it. Sounds like you got one made on a Friday arvo.

Yeah Cookie, I just pulled it of the tail stock and gave it a hard spin by hand, and you can hear the buggered bearing grinding away inside. Also, the head of the saver has several thou of wobble (play) in it, so I think your right. Hardly worth sending back to Gary GPW as the thing is only worth about $20. Anyway, I drop him an email just to let him know about it. Trust me to get a dodgy one eh :doh:

[gawdelpus]

Yeah Cookie, I just pulled it of the tail stock and gave it a hard spin by hand, and you can hear the buggered bearing grinding away inside. Also, the head of the saver has several thou of wobble (play) in it, so I think your right. Hardly worth sending back to Gary GPW as the thing is only worth about $20. Anyway, I drop him an email just to let him know about it. Trust me to get a dodgy one eh :doh:
If its like mine then the shaft support in the centre is only held in place with an "O" ring can be pulled out ok. Worth taking it apart and taking the bearing to your local bearing shop to replace it :) cheers ~ John

[seriola]

The first one I got was a tad noisy from the start and didn't last long. I like the concept though and the one I have now is a good'un. I would definitely pay more for better quality / longer lasting if available.

[seriola]

If its like mine then the shaft support in the centre is only held in place with an "O" ring can be pulled out ok. Worth taking it apart and taking the bearing to your local bearing shop to replace it :) cheers ~ John

Will have to have a closer look at mine, didn't think it came apart but if so will replace with a better bearing, cheers, Des

[Penpal]

Pariss,

I can not comment on the Mandrel Saver per se however there was a guy in the US who was having manufactured by his local machinery business his design version of a Mandrel Saver, at this time I was having trouble with my system (since cured) so I got in touch with the guy in the states who was a budding entrepeneur and could not follow my in depth discussion and also I felt I would not feed his need to improve his Mandrel Saver.

Starting at the beginning the system of nesting a Mandrel in a tiny point from a live centre which like everyone else I did, turning a full pen on a long Mandrel also meant bracing the Mandrel using fingers to reduce the vibration. Bingo I thought fingers are too important to risk in this way (seemed stupid) to me first I cut back to half a pen then 10 to fifteen years ago I eliminated the live centre nose into the Mandrel end.

Pushing this ad nausum over many years on this site and others with a view to sharing being met with so much ho hum for the last time this is my invention and the system I use on Taig Lathe, Pen Wizard, my own design faceting device, on my VL100, and on two other lathes.

Pic shows the VL100 with the Mandrel almost undressed only one bush showing
on the Mandrel sleeved into a Brass Sleeve inserted into the live centre 3/8 of an inch.after cutting off the threaded end of the mandrel. Other pics as well.
I use washers 1/4 inch to pack for undersized blanks. The tailstock pressure holds the blank. A lot of my ideas have been put into production but I feel the Mandrel Centre you speak of has need to be modified in some ways to even approach my method.
The consensus is the receiving method in the saver is sloppy, the bearings suspect two enemies of vibration free turning.

My apologies to resellers of the mandrel saver my comments based on their direct importer in the USA users fully substantiated under user reports.

Kind regards Peter.:B:2tsup:

Reading extensively the Commercial

[Pariss]

Hey Peter, thanks for posting info + pics of your great setup. To be honest, I have had zero problems using the mandrel in the standard method. I use a Groz industrial model 60deg cone centre, which enters the spindle end dimple perfectly so there is no friction. I think the main problem people have with 'out of round' pens is that the round brass mandrel nut is over tightened, and that slightly bows the spindle. Also the dead center can easily be over pressured into the mandrel spindle causing it to bow and turn off center axis. I just finished half a doz Bullet pens using the standard mandrel method, and the serenity of a quietly turning lathe coupled with a background sounds of digital quality Roy Orbison and Dean Martin, and some great Jazz, beats mowing the lawn or taking the wife shopping on a Sunday that's for sure. :2tsup::D

[Mrs Woodpecker]

My other half, who is not a pen turner in any way, but deals with machinery in his job, says it is mechanical. If you are going to drive something without a positive drive then you require inertia. Therefore, with the mandrel saver you may have to operate the lathe at a higher speed.

Using the tail stock to apply higher axial load will reduce the life of the mandrel saver. As pointed out by John I think, this is only fitted with a ball bearing.

This is absolute double dutch to me but no doubt you clever blokes will understand what has been dictated to me. I have had no trouble with my mandrel saver so far.

Good luck,

Shirley

[plantagenon]

I bought one of the mandrel savers from the USA but its still in its box at this stage. I was a bit concerned that the pressure it put on the head bearings would damage the lathe. I will have to read up a bit more on it yet. At the moment, the rare moment I get to play in the shed, I am using an adjustable mandrel which allows its length to be shortened and takes some strain off it. It seems to work ok. But I am still seeking out a high quality stainless steel mandrel in 7mm and 8mm. That should stop any bending.
Greg

[gawdelpus]

I bought one of the mandrel savers from the USA but its still in its box at this stage. I was a bit concerned that the pressure it put on the head bearings would damage the lathe. I will have to read up a bit more on it yet. At the moment, the rare moment I get to play in the shed, I am using an adjustable mandrel which allows its length to be shortened and takes some strain off it. It seems to work ok. But I am still seeking out a high quality stainless steel mandrel in 7mm and 8mm. That should stop any bending.
Greg

Just be aware that a 7mm shaft is too big for slimline tubes :) even 1/4" dia size will not fit :no: The standard shaft is a few thousandths smaller than 1/4 " dia, and all your standard bushes unless worn will also not fit :( I don't do many slims so I used 1/4" but had to ream the bushes to suit :) cheers ~ John

[Big Shed]

John is right, it isn't just 7mm and 8mm. I'm also not sure that using a stainless steel bar will overcome bending, depending on the grade of stainless it can also be soft.

Silver steel or drill rod, available from engineering places like Blackwoods is better and I have used that in both 1/4" AND 5/16", not cheap though:oo:.

I hardly ever use mandrels anymore as I they are just too imprecise. The majority of my turning is done with either no mandrel bushes, which basically limits you to turning 1 tube at the time, or closed end mandrels when I want to make a closed end.

Once you have used the no mandrel bushes, or between centre, turning you won't go back.
It does however require some investment in the bushes as you need 4 for every kit you use. I make mine from stainless 304 and haven't had to replace one yet.

I have used most of the variations and permutations of mandrels and hve never used one I was happy with, but maybe I'm just fussy.

[plantagenon]

Ok Fred, you have me interested. I am a bit of a novice at this. All my bushes run on a 7mm mandrel I buy from Timberbits as well as the bushes. The 8mm was for a Filigree pen but I can't get hold of the mandrel having bought the bushes and kits - a bit annoying!

Before I ask too much more, my lathe is a Woodfast Midi which only comes with very basic attachments. What do I need to set up the system you are suggesting and where do I find the pieces for it? I would appreciazte your advice but it will have to be in layman's terms. I only began using a lathe for the first time 12 months ago.

Thanks
Greg

[Big Shed]

Greg, first all let me emphasise that this is not my original idea. The no mandrel bush idea has been around for a while and several people are using them.

Perhaps you should read this post first to get the idea and if you have more questions by all means ask me.

http://www.woodworkforums.com/f69/new-design-bushes-turning-between-centres-114902/

Let me say straight away that Skiprat's 3 bush idea, so that you can turn 2 tubes at once, has not proven to produce consistent result and I have since abandoned that idea.

I know of only 2 people making these bushes for sale, one is JohnnyCNC on IAP, I am the other one. I have neither seen or worked with Johnny's bushes so can't commen on them.

I also make these from acetal (Delrin) for finishing, there is a thread on that as well.

http://www.woodworkforums.com/f69/no-mandrel-bushes-finishing-123004/

[cookie48]

Big Shed
Do your bushes come in all pen sizes??

[Big Shed]

Big Shed
Do your bushes come in all pen sizes??

Yes, they are made to order and can be made to any pen size, or indeed custom sizes if required.

The only thing people would need over and above what they use when turning on a mandrel is a dead centre in the head stock, available from most places that sell turning tools including McJing.

[plantagenon]

Thanks Fred

I looked at the sites you recommended. Only two follow up questions. I have attached a photo of the head and tail stocks of my lathe. They are the standard issue from Woodfast. Are they suitable for the bushes you make? Secondly, are the prices for the bushes quoted in your previous posting still the same?
Thanks
Greg

[Big Shed]

Thanks Fred

I looked at the sites you recommended. Only two follow up questions. I have attached a photo of the head and tail stocks of my lathe. They are the standard issue from Woodfast. Are they suitable for the bushes you make? Secondly, are the prices for the bushes quoted in your previous posting still the same?
Thanks
Greg

Greg, I'll get your second question out of the way first, prices have changed slightly, sets of 2 are $15.00, sets of 4 are $30.00, plus postage.

In answer to your first question, no neither of those centres are suitable for between centre turning, or indeed for turning with a mandrel.

The head stock one is a drive centre for normal spindle turning, it does not have the 60 deg poin needed for the no mandrel bushes, you will need a Dead Centre as per this one.

McJING Tools Online (http://www.mcjing.com.au/categorybrowser.aspx?categoryid=377)

In your case I think your Woodfast lathe has an MT2 internal taper in the headstock spindle, so #DE-MT2 would be the go.

The tailstock centre you have is agn suitable for spindle turning, but totally unsuitable for pen turning, either with a mandrel or no mandrel bushes. It is the most likely cause of your out of round issues. Its' point is much sharper than that of a proper 60 deg live centre and would not mate with either a mandrel or the no mandrel bushes.

You will need a live centre with a 60deg point, such as this.

McJING Tools Online (http://www.mcjing.com.au/categorybrowser.aspx?categoryid=381)

Again, the MT2 version would fit your Woodfast AFAIK.

I don't use this type very often any more as the overall diameter is rather large and tends to get in the way of the toolrest.

I use the Sorby Live Centre Set like this one:

Revolving Centres (http://www.thewoodsmith.com.au/thewoodsmith/srevcentre1.htm)

Other places sell these as well.

I have posted a thread on these, here:

http://www.woodworkforums.com/f8/live-centre-sets-116136/

Hope that clears it up, if not feel free to ask more questions:2tsup:

[plantagenon]

Thanks Fred. That was very helpful. I will PM you with an order for the bushes.
Greg

[watsrags]

Thank you Fred for your imput, it has anwsered all my current questions without me asking them.
I know this is why these pages are important to me

Trevor

[Penpal]

Hi guys,

On the previous page the last three pics in my post show a live centre a bloke made for me years ago from semi tool steel on a CandC lathe and I made the insert for my style sleeve fitting surely there are parrallell inserts reasonably obtainable in fact I will make enquiries for myself. The brass sleeve is a firm push fit and insert points easily fitted and replaced locked in place with an allen screw. Surely a doddle for a good operator with C and C anywhere with at least a gross of orders making it worthwhile..

It would be impractical for me to retrace the fellow who made mine made it cause all he wanted was one of my Slimlines in exchange years ago.

Have success.
Kind regards Peter.