Swivel Base Revisited

[Anorak Bob]

Not some Office Works chair but the base for my much laboured over dividing head mount.

I was not comfortable with the idea of a dovetail spigot and had been considering alternatives that might offer more security given my intention to mount the dividing head vertically. I located some photos of a partially dismantled universal dividing head on a French site and noticed that Schaublin used the same cam locking tee bolts to fasten that head to it's base, as they did on my simple dividing head. In the case of the heavier universal head, four tee bolts are used.

The "cam" is pretty simple and my intention is to replicate the originals by remachining M10 cap screws. The tee bolts are again simple and I think 4140 will work fine.

I was stumped for a while trying to work out how I might cut a circular tee slot. The conventional practice is an access hole from the underside for initially the cutter, then the tee bolts, typical mill vise fashion. In my case, I realised I couldn't install the tee bolts because of their barrel bodies. A removable "plug" as drawn below might be the answer. Another piece of 4140 secured with an M6 countersunk socket screw. I would prefer M8 but there is insufficient room. The location of the plug is in a position that I imagine would seldom engage a tee bolt.

Anyone notice any glaring or not so glaring omissions? And I'm not talking about the shabby drawings. I don't know how I left off the centre hole on both.:doh:

BT

[Dave J]

I had a good long look and think about any other ways, but I think you have come up with a good and possibly the only solution for those parts to be able to go into that T slot. Good thinking Bob.:2tsup:

Dave

[Stustoys]

Hi BT,
A couple of ideas,
Could you turn the tee slot in the lathe?
Would it be easier to turn a register onto the bottom of the piece that the dividing head mounts to that fits into the tee slot?
Couldn't you drill two holes from the bottom, one just big enough to pass the barrel bodies. Another much larger just into the slot to pass an over sized head tee bolt?(over sized enough that the centre of the bolt is pass one side of the barrel bodies hole before the head of the tee bolt clears the opposite side of the hole)
Stuart

[nadroj]

A 2 piece T bolt, with the bottom part screwed to the top, would allow assembly from the bottom. It could also provide adjustment for the cam action. It would be bulkier, and some way of preventing the circular T bolt from turning once adjusted would be needed - maybe a nylon friction insert?

Jordan

[Dave J]

Going off the pictures Bob posted, it doesn't look like there is much room in the base for a larger T slot, and there is not much meat between the reduced shank part for the T bolt and the cam hole. Seems like it's a tight squeeze to fit it.

Someone posted pictures of a Taiwanese lathe a while back where they come with just holes in the T slot for the compound bolts to get in. They where having trouble with the T bolt chewing the edges of the cast out around the holes when set at that angle. At least with Bob's fix it would have the patch piece to give even pressure either side of the T bolt.

Dave

[Michael G]

The only alternate that I can think of at the moment is to make the interior of the T slot bit a disc and bolt it in with some SHCS after putting in the inserts. That notch and cover arrangement looks fiddly and if the T-cam were right under it, it probably would not secure much.
Another option is to have a hole in the top that the T can be fed into in the least popular place - say at 80 degrees to the main axis - how likely are you to ever want to position something there (and with symmetry you can mirror things so it does not matter if you did.)

Michael

[Bryan]

I like Michael's idea of a bolt on mushroom. You'd get 4 or even 6 nice big screws in and it would be very secure and uniform.
Edit: Actually he said disc and that's probably all you've got room for.

[Anorak Bob]

Dave, Michael, Jordan, Stu and Bryan, thank you for thinking about this.

The bolt down disc is a pretty simple solution. It needs to be able to slide aside to allow the tee bolts to be installed. The centre bolt would provide alignment of the two major components.

I had considered a two piece tee bolt but the present 5 x 20 base ( proposed nut) of the bolt would need to be thickened somewhat to provide reasonable thread engagement with the resultant thinning of the material below the tee slot. Then a locking device would need to be devised.

Stu, holiday over? A integral register is something I have to think about. It would prevent the upper section from being mounted directly onto the mill table should the need eventuate.

BT

[Dave J]

A 2 piece T bolt, with the bottom part screwed to the top, would allow assembly from the bottom. It could also provide adjustment for the cam action. It would be bulkier, and some way of preventing the circular T bolt from turning once adjusted would be needed - maybe a nylon friction insert?

Jordan

Hi Jordan,
Not sure if this is along the lines of what you where talking about.

Bob what about something like this. The bottom could be screwed on and a few drops of Locktite would hold it there forever. The small shoulder would locate it for length.

Dave

http://www.woodworkforums.com/attachment.php?attachmentid=198489&stc=1&d=1329270895

[nadroj]

The bottom could be screwed on and a few drops of Locktite would hold it there forever. The small shoulder would locate it for length.


That's one way, or the other end could be threaded.
Another idea: One piece, but using a modified oval shape to engage the T slot. Its width narrow enough to fit through from the top, and its length and shape sufficient to provide adequate clamping area when rotated to its working position. The hole for the cam would be offset by an angle, such that when it's in the correct position so is the clamp.

Jordan

[Anorak Bob]

I'm working through the suggestions.

JP,

I made a skewable nut for my table adjuster and while it works well in that application, the amount of engagement available is a bit limited on this current project. I will explore the idea further though with a drawing. Here's the two part tee bolt. The thread would be M8. Loctite is easy but makes dismantling a problem. Maybe a M3 or 4 socket set screw with a brass pad might be a better option.

BT

[RayG]

Hi BT,

I don't have any better suggestions that those you've already got,
But I like Jordan's two part T bolt idea, instead of a locking screw, you could use loctite thread lock ( a little less permanent than loctite 401 :) )and mill a screwdriver slot on the bolt head.

Regards
Ray

[nadroj]

A little locally applied heat destroys the Loctite bond.
It doesn't need to be so hot as to affect the metal parts.
I guess it's not as nice as a purely mechanical solution.

Or, what about a very wide slot, so the bolt doesn't need to have 3 diameters, only 2 with the top part large enough to engage the cam.

Jordan

[Anorak Bob]

Or, what about a very wide slot, so the bolt doesn't need to have 3 diameters, only 2 with the top part large enough to engage the cam.

Jordan

I will sketch up a version incorporating that idea tomorrow Jordan.The tee slot is located within the 80mm width of the upper mount to exclude swarf. Room may be at a premium.

BT

[Anorak Bob]

The non waisted tee bolt as per Jordan's suggestion. I now have to work on a way of holding the two major parts together whilst providing accurate rotation.

BT

[Anorak Bob]

I thought that it was time I rekindled my interest in this project . After a mishap with a slitting saw I thought it would be prudent to double the previously intended pair of cam locking tee bolts. Surprising how quickly 2 horsepower can work something loose.:o

Now I have to work out a way of cutting the circular tee slot. Should be fun.

BT

ps. The cleaning of the lathe took longer than the turning of the base.

[Stustoys]

Hi BT,
Four has to be better than two :)
Now for rotation location, How about and oversized ring bolted and pinned in 8(?) places then turned to a slip fit in the tee slot. Then bore four holes in it to past the tee bolt?

Stuart

p.s.Did I suggest the same idea in an earlier thread?

[jhovel]

I have a couple of vices with circular T-slots in their swivel bases. Both have a square hole from the bottom into the T-slot to insert the T-bolts through. If you mill that hole first as a pocket from underneath, you can then break into it when milling a circular slot into the top. Once that's done, you can insert the T-slot cutter by itself from underneath and remount the base on the rotary table. Grab the shaft of the cutter with your collet chuck and start milling the sides of the T slot.
On the other hand, one of my swivel bases has a round hole from the top as well - at an odd angle to the mounting lugs - presumable to minimise the chances of having a T-bolt sitting right in the centre of the hole and only holding by the very corners. The T-slot cutter can be lowered into the circular slot and cut the sides from the top with that method.
Show us how you end up going about it.
I guess you could also turn T-slots on the lathe with a special boring bar type tool....
Cheers,
Joe

PS: have you considered using the mounting method of the Douglas shaper vice swivel base? No T-slots at all?

[Ueee]

Hi Bob,
I was wondering what the part you were drilling with you sensitive head was for, now i know! I think Joe's suggestion of not using T slots would be the easiest, i don't exactly know what the douglas vice is like but i imagine its the same as the locks on most rotary tables? Having said that, where is the challenge in making it easy??? Look forward to seeing how you do it.

[Anorak Bob]

Hi Bob,
I was wondering what the part you were drilling with you sensitive head was for, now i know! I think Joe's suggestion of not using T slots would be the easiest, i don't exactly know what the douglas vice is like but i imagine its the same as the locks on most rotary tables? Having said that, where is the challenge in making it easy??? Look forward to seeing how you do it.


As per the photo below Ewan.

I am now committed to the cam lock tee bolt idea. Michael G suggested a bolt down plate to form the inner land of the tee slot. It's either that or a single plug as suggested in my cartoon at the commencement of this thread.

I think whatever I do, I will cut a 10mm wide circular slot to the depth of the tee slot then bore a hole inboard of the slot to allow access for the tee slot cutter

Joe's Douglas like setup would have been fine if my locking or clamping screws were accessible from the top. Would have been a really simple solution but not one that works in this application.

Stu's registration ring would have also been a simple thing to include while machining the underside of the upper section. It would be a hell of a lot of work now. I plan to use a central locating pin. Haven't worked that one out yet.

BT

http://www.woodworkforums.com/attachments/f65/201939d1332150943t-douglas-shaper-vise-photographs-2012-03-19-013-large-.jpg (http://www.woodworkforums.com/attachments/f65/201939d1332150943-douglas-shaper-vise-photographs-2012-03-19-013-large-.jpg)

[Anorak Bob]

I'm wondering how I would go doing nothing more regarding covering up the tee bolt access hole ie. leave it as shown in photo 4. If the upper section of the base was set at 45 degrees, one of the 4 tee bolts would only engage the outer land of the tee slot. The tee bolt should be a sliding fit in the upper section which should minimise racking.

The other alternative, Michael G's suggestion, is to turn off the entire centre section of the base and replace it with a bolt on plate. I could comfortably fit six M5 cap screws or four M6. A lot more work.

I know it's easy to recommend the laborious route when you aren't the provider of labour but what do you blokes reckon, worth the risk of an Achille's heel with the soft option?

BT

[nadroj]

I tend towards the removable plate option, as I don't see any minus with it, apart from the extra work.
But as you say, it'd probably be OK 95% of the time using it as shown.

Jordan

[Anorak Bob]

It's the 5% that worries me Jordan. Maybe I just need to harden up and hack that nicely turned centre section off and fit a plate.

BT

[Bryan]

I guess a compromise would be to mill out a section and fit a small retainer. So maybe two screws instead of six.

[Stustoys]

What about a small plate with a single screw?
Even one bolt is going to do alot but I think its just as important that it stops the tee bolt racking.
Of course you have to work out localing the table first.

Stuart

[Ueee]

I guess a compromise would be to mill out a section and fit a small retainer. So maybe two screws instead of six.

That's the way I would go....machine out a half moon and use a bolt either side of the hole. Easy straight machining and only 2 bolts.

[Anorak Bob]

What about a small plate with a single screw?
Even one bolt is going to do alot but I think its just as important that it stops the tee bolt racking.
Of course you have to work out localing the table first.

Stuart


Here is a plan ( a section actually). The plate is a six M5 screw affair. The "screw" is threaded 12 x 1 and 10 x 1. The "nuts" are either slotted or drilled to accommodate a pin spanner. Any way you look at it, there is a fair amount of rooting around. The whole project has been that way, I suppose there is no good reason to back off now.

BT

[Stustoys]

Here is a plan ( a section actually).
LOL a little draftsman's humour :)

How about something like this? Then you aren't locating off the removable part.
With a counter bore into the table section to local the pin(Which is really the only alignment that matters right?).
Why the nut??

I am wondering though it you are weakening the whole to possibly strengthen part? I thinking the one I sketched above is about 1/6th of a full circle, if you get what I mean.

Stuart

[Anorak Bob]

Stu,

The single bolt down insert or plug is by far the easier option and as you suggest maintains the integrity of 5/6ths of the inner portion of the tee slot.

With the original Schaublin cam lock tee bolts there is a bit less than 1mm play between locked and unlocked. It would be possible to do away with the nesting nuts and just have a spigot screwed into the upper profiled* section and simply locate the plain end of the spigot in a close fitting hole in the base. My only concern about the absence of the nuts which pull the assembly together, would be when the swivel base is mounted vertically.

I will draw another "plan" tomorrow.

* the profile is that of the Schaublin 102 lathe bed. The simple dividing head can fit on that lathe.

BT

[Stustoys]

Hi BT,
Where is the update? hehe
You could do something like this. Scraping the face on the washer to get the fit you want. You'll be awhile wearing it out and then you'd just have to scrap a little more off.

[Anorak Bob]

Hi BT,
Where is the update? hehe
You could do something like this. Scraping the face on the washer to get the fit you want. You'll be awhile wearing it out and then you'd just have to scrap a little more off.

I like it Stu, saved me some pencil lead.:2tsup: Far less rooting around than my double banger nut idea.

BT

[Anorak Bob]

I decided to pursue the easy option and make an insert to the fill the cutter/tee bolt access hole in the base. There was only sufficient room to allow the fitting of a single M6 countersunk socket screw from the underside of the base, and at the same time provide adequate space for the connecting stud and washer a la Stu's suggestion. The tee slot cutter has to be left insitu while I clean up the edges of the slot with an end mill.

I am fearful that when I take a finishing light skim across top of the base, I might expose the very end of the blind tapped hole in the insert. Fingers crossed. Then I have the task of graduating the thing. 360 lines without a glitch. I won't ask my mate with the broken vice to come around to watch.

BT

[welder]

once again Bob that's exquisite machining looks fantastic :2tsup:

[Anorak Bob]

Soft focus camera work Andre. Always does the trick.:2tsup:

I'm not out of the woods with this thing yet. After the scribing of 360 lines there's the stamping of the degrees. I already sweating thinking about it.

[Ueee]

Nice work Bob:2tsup:

Have you made yourself a jig for aligning the number punches? I can probably dig out a link to one if you need it. I was helping a friend punch some letters on a sword pommel last week (i was just striking) In 4 letters he managed to get the C back to front twice....:doh:

[BobL]

once again Bob that's exquisite machining looks fantastic :2tsup:
+1



I am fearful that when I take a finishing light skim across top of the base, I might expose the very end of the blind tapped hole in the insert. Fingers crossed. Then I have the task of graduating the thing. 360 lines without a glitch. I won't ask my mate with the broken vice to come around to watch.

All sounds very familiar!

[Stustoys]

Hi Bob,
Great work as always. As soon as I saw your pictures I thought "now why didnt I think to suggest bolting that part from the back?", luckily you're checking my work lol
One thing I found handy for dividing the straight knurl for the thumb screw was a piece of paper taped over the seconds graduations as I was only going to the nearest minute. You'll be on full degrees so could tape over most of the graduations on the hand wheel as well.

Stuart

[BobL]

Have you made yourself a jig for aligning the number punches? I can probably dig out a link to one if you need it. I was helping a friend punch some letters on a sword pommel last week (i was just striking) In 4 letters he managed to get the C back to front twice....:doh:

I wouldn't mind seeing a jig or two for this sort of thing. Maybe start a new thread on this ?

Also how the heck does one get even indentation of characters especially when different characters seem to require different amounts of impact.

[Anorak Bob]

+1



All sounds very familiar!

I knew that would strike a chord Bob.:U

[Anorak Bob]

I wouldn't mind seeing a jig or two for this sort of thing. Maybe start a new thread on this ?

Also how the heck does one get even indentation of characters especially when different characters seem to require different amounts of impact.

I searched for graduating on the forum and found this -

http://www.woodworkforums.com/f65/cross-slide-threading-stop-135919/#post1324190

I will make a jig that has a locating spigot that will fit in the centre hole and one end will clamp into the tee slot and the other will hold the punch. What I learnt from my previous efforts:doh: is to write the numbers on the workpiece in their appropriate locations and also to test the punch position with a piece of masking tape on the workpiece. Any way you do it, it's stressfull.

BT

[Ueee]

This is the jig i saw found some time back. http://www.neme-s.org/images/PDF_Files/Making_Graduated_Collars1.pdf Its very simple. The only thing is he is doing it on the lathe:o. I was planning something similar only not on the lathe, like BT with a spigot for the center and a beam with points to hold the guide. As for how hard to hit each different punch.....with the jig the positioning should be repeatable so you could go back for another hit if needed.

[Anorak Bob]

This is the jig i saw found some time back. http://www.neme-s.org/images/PDF_Files/Making_Graduated_Collars1.pdf Its very simple. The only thing is he is doing it on the lathe:o. I was planning something similar only not on the lathe, like BT with a spigot for the center and a beam with points to hold the guide. As for how hard to hit each different punch.....with the jig the positioning should be repeatable so you could go back for another hit if needed.

Ew.

I had seen that jig years ago and made something along the same lines when I faced the task of stamping the degrees on my Hercus look a like rotary table. An awkward task.

BT

[Anorak Bob]

I cleaned up the edges of the tee slot on the mill this afternoon then set the base up again on the faceplate. The plug is a reasonable fit, the finish on the cast iron isn't. Cast bar, in my experience, varies in hardness. The final cut was about 0.001 deep witth the slowest feed . Maybe too slow. My fear is that if I have another go I'll expose the end of the blind M6 tapped hole in the plug. Me being anal I suppose, no one will ever see it.

BT

[Stustoys]

Hi BT,
Looks pretty good to me, but I can be a little rough:D. It does seem to have got worse after the first 10mm or so. Before you worry about another cut, have you spotted it to see how flat it is?
Whats it bolted to in the pictures?

Stuart

[Anorak Bob]

Hi BT,
Looks pretty good to me, but I can be a little rough:D. It does seem to have got worse after the first 10mm or so. Before you worry about another cut, have you spotted it to see how flat it is?
Whats it bolted to in the pictures?

Stuart

Stu,

It's not worse, the finish is dead smooth, just looks sh..house. It's bolted to the Hercus faceplate The problem that I will encounter if I start scraping the thing if it is not flat, is that any subsequent graduating will be illegible. Bit over a barrel. I need a surface grinder.

BT

[Ueee]

Looks good in the pics Bob,
Really, how much of it is going to be visible? Did you clean the first 1/2" up for the graduations or is that just how it cut?
I would spot it like Stuart said just to check its not high in the middle, at least that way you should not need to scrape the edges....Any way, its not too hard to file the scrape marks down to a smooth finish around the edge.

[Stustoys]

Hi BT,
Smooth isnt flat.(have you checked out how much concave yor lathe cuts, if any?)
You need to put it on a flywheel grinder.


Not so sure about the graduating being illegible, others might be able to help there. Might look great.

Stuart

[Anorak Bob]

Stu,

I wasn't suggesting smooth was flat. Smooth as opposed to rough. I'll blue up the little surface plate tomorrow and see how things look. Sadly there is no flywheel grinder in the garden shed.:no:

Ew,

What's visible is everything not covered by the 130 x 80 tee slotted upper section. In other words, a fair bit. Let me do some checking with the granite plate tomorrow . This is becoming a xxxx of a job.


BT

[Bryan]

Not so sure about the graduating being illegible, others might be able to help there. Might look great.

I scraped the top of my cross slide, where the compound mounts, and the numbers are harder to read now. The scraping scatters the light. It had to be done and I'm getting used to it. I don't know how you could remove the scrape marks without sacrificing the flatness, except with a surface grinder. Maybe a lap - a proper one like Phil's?


I cleaned up the edges of the tee slot on the mill this afternoon then set the base up again on the faceplate. The plug is a reasonable fit, the finish on the cast iron isn't. Cast bar, in my experience, varies in hardness. The final cut was about 0.001 deep witth the slowest feed . Maybe too slow. My fear is that if I have another go I'll expose the end of the blind M6 tapped hole in the plug. Me being anal I suppose, no one will ever see it.


What if you lower the area where the markings will go - only a couple of thou - and leave a turned finish on that, then scrape the higher mating surface true?

[Stustoys]

What if you lower the area where the markings will go - only a couple of thou - and leave a turned finish on that, then scrape the higher mating surface true?
Now that sounds like a good idea! As Bob has a square spinning on top there would be a risk of scratching the divisions as the corners pass over then.

I happen to know a guy with a flywheel machine that I might be able to talk around, but you didnt leave us much to play with.

Stuart

[Anorak Bob]

Boys, the problem with lowering the markings is that the intended marking location is directly above the outer land of the base's tee slot. I feel a bit like I'm painting myself into a bit of a corner with this project. :no:

I blued up my man junior plate and gave the base a blueing. F...ing hopeless. The centre was the only part making contact. I repositioned the tool and adjusted the gib screws to accommodate some of the wear in the cross slide. Better result. I also used a fresh insert. I noticed that yesterday's facing effort didn't appear flash because the insert was worn. After the adjustments the result improved. I could not lift the baseplate off the granite, I had to slide it off sideways. I imagine that I will need to scrape the underside of the round base and probably the bottom of the top profiled section.

I have marked the intended graduation location with a blue marker. It's not like there is an expansive view if they are in that location. There is alway something waiting to bite you when you make up stuff on the hop.:doh:

BT

[Anorak Bob]

The method of securely mounting the tee slotted upper section on the round baseplate as suggested by Stu* has been adopted ( with naturally a couple of minor tweeks :U). http://www.woodworkforums.com/attachments/f65/216314d1342697469t-swivel-base-revisited-swivel.jpg (http://www.woodworkforums.com/attachments/f65/216314d1342697469-swivel-base-revisited-swivel.jpg)

I had started off badly by thinking I could accurately tap a 12 x 1 with a tap held in a tap handle in turn held in the tailstock mounted chuck. 5 thou runout ended that idea. I had a very small threading tool that I reground to 60 degrees and cut a 14 x 1 thread and counterbored the hole to a depth of 3.5mm.

My first few attempts at making a spigot for the original 12mm thread were unsuccessful. I had been using 4140 but the swarf ended up twirling around the nicely turned bar and marred the finish. I gave up on the chrome moly and used 1214 for the 14mm threaded spigot. Rather than rely on a drill bit to drill the tapping hole for the M6 screw, I used a tiny boring bar to bore the 5mm hole. I had a go with the very small threading tool shown in the photos mounted directly in a collet but there was insufficient clearance ground below the cutting edge. It would be fine in a large diameter bore but not 5mm.

All worked out well in the end. Next step is the cam locking tee bolts.

BT

[Abratool]

The method of securely mounting the tee slotted upper section on the round baseplate as suggested by Stu* has been adopted ( with naturally a couple of minor tweeks :U). http://www.woodworkforums.com/attachments/f65/216314d1342697469t-swivel-base-revisited-swivel.jpg (http://www.woodworkforums.com/attachments/f65/216314d1342697469-swivel-base-revisited-swivel.jpg)

I had started off badly by thinking I could accurately tap a 12 x 1 with a tap held in a tap handle in turn held in the tailstock mounted chuck. 5 thou runout ended that idea. I had a very small threading tool that I reground to 60 degrees and cut a 14 x 1 thread and counterbored the hole to a depth of 3.5mm.

My first few attempts at making a spigot for the original 12mm thread were unsuccessful. I had been using 4140 but the swarf ended up twirling around the nicely turned bar and marred the finish. I gave up on the chrome moly and used 1214 for the 14mm threaded spigot. Rather than rely on a drill bit to drill the tapping hole for the M6 screw, I used a tiny boring bar to bore the 5mm hole. I had a go with the very small threading tool shown in the photos mounted directly in a collet but there was insufficient clearance ground below the cutting edge. It would be fine in a large diameter bore but not 5mm.

All worked out well in the end. Next step is the cam locking tee bolts.

BT
Bob
Once again nice work.:2tsup:
I was particularly impressed with the collet held boring bar.
A very convenient tool.
regards
Bruce

[Anorak Bob]

Bob
Once again nice work.:2tsup:
I was particularly impressed with the collet held boring bar.
A very convenient tool.
regards
Bruce

Ha Ha, You're just happy that I'm using that gumby 1214 stuff Bruce.:U I have to admit it's beautiful to work with. Imagine holding a bit of tough stuff in the jaws of the baby Sherline chuck and expecting it to stay there.

Those W20 collet holders have worked out to be dough well spent.

BT

[Stustoys]

Hi BT,
Nice going. Is it to early to say the end is in sight?
Are you going to stay with the sine bar?

Stuart

[Anorak Bob]

Hi BT,
Nice going. Is it to early to say the end is in sight?
Are you going to stay with the sine bar?

Stuart

Well Stu, apart from some careful scraping I'm tempted to leave the base in its unadorned form. Graduating with a pointed tool will raise burrs and create yet another problem. Far easier to go the soft option with the whizzo mini sine bar.

I don't imagine that the tee bolts will be real easy. Rather than struggle with 4140 from the outset, I think I'll do the trial and erroring with 1214. I'll start with the job of turning the cap screws into cams.

BT

[Abratool]

Bob
I reckon you will get a lot of use out of that little Sine Bar.
After a lifetime of improvising with feeler gauges, adjustable parallels, telescopic gauges, planer gauges etc to set the opposite height for the Sine of the predetermined angle, I finally lashed out on a brand new low priced set of Gauge Blocks from the USA. Shars..... Sub Continent Mfg
They were $76
Now, I know these are not in the same league as Starrett, Johansen, Mitutoyo etc however since getting them Ive found them to be very handy (like all tools) & in all honesty, accurate enough.They wring together & are convenient for all sorts of jobs.
Sine Bars are also very useful tools :2tsup:
regards
Bruce
ps Here are a couple of photos of my 3 inch Sine Bar in use & a photo of the Gauge blocks

[Ueee]

Bruce,
I have been looking at the blocks from ctc, no doubt out of the same factory as yours. My one concern was the ability to wring them together, it is good to know they do. To see van da waals forces at work I think is really something amazing.

[welder]

thanks for more info on the Chinese gauge blocks I am also considering a set from ctc not sure whether to get imperial as I have two imperial sine bars or metric :?

[Ueee]

thanks for more info on the Chinese gauge blocks I am also considering a set from ctc not sure whether to get imperial as I have two imperial sine bars or metric :?

Easy Andre, get one of each:D

[Abratool]

Easy Andre, get one of each:D
Andre & Ewan
It was not difficult for me, as you have probably noticed before.
I know & accept we live in the metric age.That will not change.
But all of my thinking , Lathe, Mill, Stock, Micrometers, Verniers Dial Gauges, Sine Bars, Everything is Imperial. Everything:U
When you blokes talk .05mm etc my brain is immediately converting to "meaningful" Imperial.
Not a problem, except when it comes to Screw Threads. One has to carry Metric Taps & Dies, Imperial...BA, UNC, Brass, BSW, BSF, Model Engineers, & so the story goes on, together with No Drills, Letter drills, Fraction Drills, Metric Drills & so the story goes on.
However as Andre says its good to have tools on hand.:2tsup:
regards
Bruce

[welder]

Well I think I will take a gamble on a ctc 37 piece imperial set next time I have some cash. I find it easy to work in imperial or metric although I do find imperial a bit of a different language after 12 inches. I was kind of forced to work in imperial as my first lathe was imperial and most of the tools I inherited are imperial :2tsup:

ps Thanks Ewan and Bruce for your comments I will stop hijacking Bobs thread

[Stustoys]

Hi BT,
I was worried about the burrs also but less so that the number punch burrs. Thinking about it a little more you'd have to 0 the graduations each time you mounted the base, now you can skip that part.

Hi Andre,
If there nearest 0.0001" isnt good enough you are going to have more problems that "not having metric gauge blocks".
Better still go metric, then you can be "to the closest micron"

Stuart

[Anorak Bob]

After a week's rest and recreation in the Tool Capital, I finished off the eccentric "bolts" that facilitate the clamping of the tee slotted upper section to the round base. The bolts began life as M10 x 70 cap screws. I had to turn a half millimetre offset with a resultant 9mm diameter waisted section on the unthreaded shank of the screw. I made a bush from some 3/4" 1214 and drilled the offset hole with a slot drill in the mill. I then installed a 5mm socket set screw in the side of the bush to lock the cap screw in place. I struggled trying to accurately centre the bush in my little Griptru chuck thinking the Griptru would afford pretty good repeatability. It didn't so I made another bush from some 20mm PG 4140 and mounted it in a ER chuck trued in my 4 jaw. ( I have a 20mm collet but not a 3/4" collet). Having stops at both ends of the saddle made the job pretty straightforward. High speed steel and undiluted soluble oil resulted in an ok finish. The cutter worked well, providing a radius to both ends of the cut in a similar fashion to the Swiss original.
The tee bolt, stud, whatever isn't going to be as easy. I better start thinking about how the hell I'm going to make them. :no:

BT

[Ueee]

Looks good Bob:2tsup:
Nice idea to use socket head bolts.
Surely the t bolt studs shouldn't be that hard, machine large dia on the end of a longish bar, cut the groove, machine the smaller dia/end down. Then put the bar in an RT on its side with a 3 jaw, drill, counterbore, then return to lathe and part off. It doesn't matter if the bar goes back in the lathe with radial runout as you will only be parting. Or am i missing something......?

[Stustoys]

Hi BT,
Nice start. Are you going to polish up the shaft of the bolts? it is a bearing surface after all.

How about making one leaving this face oversized and not reduce the diameter. Then you could measure the clamp distance and the unclamp distance(for where the reduced diameter starts) and make your adjustments.

Stuart

[Log]

Tis coming along good Anorak Bob, every bits a winner.:2tsup:
You need four? so two spares?:2tsup:, or are you fitting the 2 extra in the base you had move during the slitting saw episode. That's if I'm thinking right from info in post #16.

Good luck with the cam actuated tee bolt thingamajigs.

Cheers.

[Anorak Bob]

Log , two are spare. I typed out a detailed response but for some strange reason I can't post that response.

BT

[Big Shed]

Bob, what browser are you using?

Did you use Quick Reply or did you Go Advanced?

[Anorak Bob]

Spares Log, I only need four. A lot easier to make while the lathe was set up than starting from scratch. Originally I had intended using two tee thingamajigs. Safety in numbers.

I'm wondering how I will machine the groove in the thingamajig (clamp). The internal lower corner must be sqare or slightly undercut so that it bears evenly on the cast iron tee slot.

I'm thinking of making a mock up clamp with a screw on base to enable the establishment of the correct overall height, a height that suits the cam and ensures proper locking. Jordan and Dave suggested this a while back.

http://www.woodworkforums.com/f65/swivel-base-revisited-148228/#post1445539

I have to scrape the underside of the rectangular top section before I venture too far with the clamps.

BT

[Anorak Bob]

I see that the troublesome reply has finally made it.

I use Windows Explorer 7 Fred and it was a quick reply . That could be the problem maybe because it contained a link. Next time I will try advanced.

Bob.

[Big Shed]

I see that the troublesome reply has finally made it.

I use Windows Explorer 7 Fred and it was a quick reply . That could be the problem maybe because it contained a link. Next time I will try advanced.

Bob.

Bob, most of these types of reported problems have been with various flavours of IE, mainly IE9. There have been suggestions to switch compatibilty mode on and that seems to have solved peoples' problems, but that could have been just for IE9.

I use Firefox (V15) and have had no problems of that kind at all, other people that were using IE have switched to FF and found that their problems diappeared.

Not suggesting you change, but keep it in mind.

[Anorak Bob]

I made a trial one this afternoon. It might have been successful if I hadn't turned too much off the 20mm diameter base section in an attempt to get the cam to work correctly. A drawing might have helped.:doh:

Learned a couple of things in the process. I should have used a 12mm slot drill to drill a guide for the 12mm drill bit. It would have prevented chatter. I was concerned that the cutter I used to machine the groove would leave a poor finish being a piece of high speed steel ground to function as a parting off tool. Held in the front tool post, it did the job.

To salvage this attempt, I will replace the integral 20mm section with a screw on replacement and adjust the length of the 10mm section until it works properly. Then when I have established the correct dimensions, I'll move onto the real ones.

I might polish up the cams Stu, depends on the finish I achieve when milling the hole through the thingamajig.

BT

ps. I have installed Firefox.

[Stustoys]

I might polish up the cams Stu, depends on the finish I achieve when milling the hole through the thingamajig.

Hi BT,
Just to be care*, it wasnt the finish on your cams I was talking about, it was the factory finish on the bolts.

Stuart

*clear

[Anorak Bob]

A dunk in some Blackfast and you won't be able to tell the ring-in from the real thing.:U

[RayG]

Hi BT,

Looking good, I'm impressed as always with the attention to detail that shows.

Just a dumb question, what are the rules of thumb for cam type locks, I imagine that the less eccentric the cam the more force you can apply and the better it locks, a highly eccentric cam I imagine wouldn't lock as well.

Is it the same friction calculation as a taper?

Regards
Ray

[Anorak Bob]

Not a dumb question Ray but a dumb answer from me. It was a case of monkey see monkey do. I copied Schaublin's cam.

I had a look in a couple of my books and found some simple and more complicated answers to your question. I will create a new thread with some photographed pages because there may be broader interest.

Barleese on the taper comparison.

BT

[Anorak Bob]

.. and the project being slipped into the Sulo bin.

I cut off the 20mm diameter base of the clamp and reduced the length of the waisted section by 0.005". With a new base secured by means of a M6 screw, I assembled the swivel base. Inserting the cap screw cam was a bit difficult. Then I realised why.:doh: The cam can only be installed with the clamp in the locked position , ie, top dead centre. Because I had a tiny amount of play, the cam did not pull the clamp up as tightly as it should have if it was fitting properly. Fitting properly would have meant that I would not be able to disassemble the two parts of the swivel base. :no:

I will now make the tee clamps as 2 piece affairs, the same as the trial version. I will bore an access hole in the underside of the round base to facilitate installation of the 20mm diameter screw on component. I still needed to have the removable plug in to top to enable the use of the tee slot cutter which had a 1/2" shank. The tee slot is 10mm wide.

BT

[Ueee]

Oh dear.......another way around this would be to machine the end of the cam down to 8mm and putting a bush in the end of the cam hole. Then it could be assembled at any point. An m6 bolt in tension should be plenty strong though, and much easier to implement.

[Stustoys]

I'd been thinking something along the lines of "why isnt the end smaller than the cam?" but I hadnt taken it to the "can't get it together" conclusion.
The holes for the cams are bored already correct?
With the M6 grub screw design, at least the cams cant fall out.

Stuart

[Anorak Bob]

Boys,

When the cap screw cam is tightened it's lifting the tee clamp up and pushing the 10mm diameter shank of the cap screw down. Working correctly, it would be jammed tight with little chance of removal. Reducing the diameter of the outboard end to less than 9mm wouldn't help me.

Schaublin's use of the cam operated fittings is somewhat different. They are installed in the simple dividing head body then the head is slid onto the tee slotted saddle with the cams obviously loosened off. Then they are tightened. I can't do that.

I had wondered why Schaublin counterbored and countersunk the holes in the clamps. Without the countersink the removal of the cam would be real tricky.

Live and learn.

BT

[Stustoys]

But*, if the outboard end of the cap screw was reduced to 8mm. Couldn't you insert it when the thingamajig was loose/open/on bottom.

Stuart


*at least as I'm seeing it in my head

[Ueee]

I have just spent my quiet shower time thinking about how this all works (you try thinking about things like this whilst children are screaming....). I have wrapped my head around why it works with the dividing head and not for the base, but i'm with Stu, i can only see it working if the end of the cam is 8mm. !f the top of the hole in the t thingy is 1mm lower than the cam hole (when it is lifted up in the t slot) then the cam could be put in bottom dead center and you have 1mm of tightening range......in my head anyway.

[Anorak Bob]

I don't want you boys thinking you are orphans, I have been pondering this also.

Stepping the outboard end down to 8mm would mean there was the likelihood of the cap screw cam falling out if the swivel base was mounted vertically, one of the main reasons for undertaking the project.

I am now wondering if I have the thickness of the 20mm diameter base of the tee clamp too great. If it is too thick I won't have the 1mm play offered by the cam offset. That could well be the reason for being unable to remove the cam in any position other than TDC. If I had the full 1mm travel, I'm thinking that I should be able to remove the cap screw cam at BDC.

Should isn't does. More testing tonight.

BT

[Stustoys]

Stepping the outboard end down to 8mm would mean there was the likelihood of the cap screw cam falling out if the swivel base was mounted vertically,

Well we agree on that :)
Though and extra groove in the cam bolt and a grub screw into said groove could fix that.

If I had the full 1mm travel, I'm thinking that I should be able to remove the cap screw cam at BDC.
I'm afraid not BT*, as is, the cam bolt will only pass through the thingamajig in the fully up/locked (plus a little bit more) position.

Stuart

*As I'm seeing it.

[Steamwhisperer]

HI Bob,
I have read and re-read this and I must be missing something.
Can you only insert/remove the eccentric pins in the TDC position?
Is your maximum clamping position only in the TDC position?
Would it be true to say that through 180 degrees rotation you go from maximum slack to maximum tight?
I would have thought that the pin could be removed when the eccentric pins were in anything other than the clamped position ie TDC hence the lead in/out chamfer.
I also would have thought that a rotation of less than 180 degrees would be the target for maximum clamping effect (assuming 180 degrees is your distance of rotation for maximum clamping effect and you have that at TDC)
I just know there is something staring me in the face that I have missed.

Phil

[Stustoys]

Hi Phil,
The cam area has a smaller diameter(9mm) than the bearings either side of it(10mm).
So the cam area cant lift the thingamajig higher than the bearings lift the thingamajig(when being inserted).
The position of the cam at TDC or BDC has no effect until the 10mm bearing has passed through the thingamajig.
Think about it using the shank of a bolt that doesnt have the cam machined on it. If the thingamajig is long enough that the bolt can be slipped in it then cant pull the thingamajig any higher to clamp. (though with the cam you would be able to slacken it off 1mm).

Stuart

*of course I could be wrong :)

[Anorak Bob]

Phil and Stu,

I went up to the shed and had a proper look at the original cam/tee clamp setup. It is not possible to remove the cap screw cam when the dividing head is mounted on the tee slotted saddle, both Schaublin's and my pretend version. Dismounted, the two components fall out. I guess that last thing you would want is for the cams to fall out when you have the dividing head set up in some weird position like in the photo below.

I don't think I have any choice other than to bore an access hole from the underside and to make the tee clamps two piece. But before I do that I will have a go with a thinner 20mm diameter base on the tee clamp.

BT

[Stustoys]

Hi BT,
The second one will be a piece of cake ;)


I don't think I have any choice other than to bore an access hole from the underside and to make the tee clamps two piece. But before I do that I will have a go with a thinner 20mm diameter base on the tee clamp.


You could machine the end of the cam bolts to 8mm and fit a bush to the base as Ewin said earlier(adding something to stop the cam bolts falling out). The only problem I see with your idea of two piece thingamajigs is that you must remove the base from the mill table to get at the bottom, though I'm not sure how that could be an issue as even if you couldnt remove the top of the swivel base from the bottom you can still remove the dividing head from the top..... right?
Your idea would also make adjusting the length of the thingamajigs easier than making them in one piece.

Stuart

[Steamwhisperer]

Hi Phil,
The cam area has a smaller diameter(9mm) than the bearings either side of it(10mm).
So the cam area cant lift the thingamajig higher than the bearings lift the thingamajig(when being inserted).
The position of the cam at TDC or BDC has no effect until the 10mm bearing has passed through the thingamajig.
Think about it using the shank of a bolt that doesnt have the cam machined on it. If the thingamajig is long enough that the bolt can be slipped in it then cant pull the thingamajig any higher to clamp. (though with the cam you would be able to slacken it off 1mm).

Stuart

*of course I could be wrong :)

Thanks Stuart. Painfully obvious now:-
Old Timers disease must be setting in:D

Phil

[Anorak Bob]

Hi BT,
The second one will be a piece of cake ;)


... The only problem I see with your idea of two piece thingamajigs is that you must remove the base from the mill table to get at the bottom, though I'm not sure how that could be an issue as even if you couldnt remove the top of the swivel base from the bottom you can still remove the dividing head from the top..... right?


Stuart

I'm sorry Stu, I should have responded earlier.

The entire assembly must be removed from the machine to separate the tee slotted upper section from the circular base anyway because of the incorporation of the Mason:U lock. http://www.woodworkforums.com/f65/swivel-base-revisited-148228/index4.html#post1538510

The dividing head would be installed after the swivel base is mounted on the machine if I was attaching the setup onto the vertical face of the longitudinal slide. Otherwise it could be left saddled up.

I have to devise a stop that prevents the dividing head from sliding off the swivel base when it is mounted vertically. Ideally, it would be something that enables the dividing head to be slid up from the bottom, towards the cutter, Centricator or whatever else is mounted in the spindle. Then the stop is latched into place.

Aren't you happy you haven't got a bitty little milling machine?

BT

ps. It turns out I'm not alone with the use of a two piece thingamajig. Have a look at the seller's photos. http://www.ebay.de/itm/Drehmaschine-Support-Multifix-Habegger-Deckel-Frasmaschine-/140851303268?pt=Industriemaschinen&hash=item20cb645364

[Stustoys]

Hi BT,

because of the incorporation of the Mason:U lock.:doh:


Aren't you happy you haven't got a bitty little milling machine?
But it doesnt look near as pretty as yours and sure takes up a lot of room.



Ideally, it would be something that enables the dividing head to be slid up from the bottom, towards the cutter, Centricator or whatever else is mounted in the spindle. Then the stop is latched into place

Thats a little tricky, it would be nice if it was some sort of ratchet so locked itself as you slid it in place, but that might end up making removal a 1.5 hand operation, would that be any better that 1.5 hand loading?



ps. It turns out I'm not alone with the use of a two piece thingamajig.
Currently I like your thingamajig better. Though the way I've been going lately I'm likely missing something :D

Stuart

[Anorak Bob]

Apart from some scraping, for all intents and purposes it's completed.

The thingamajigs had to be two piece and an access hole was required in the underside of the base. I made the thingamajigs from 4140 and experienced some tearing when I countersunk the removable bottom disc. Maybe too long a boring tool. I established the required length of the tee slot clamps by trial and error on the test piece. The cams lock nicely. The cams received a bath in Blackfast.

I'm happy with the end product. Certainly a lot of rooting around for such a simple thing.

Thank you all for your advice and support during this lengthy ordeal.:U

BT

233883

[Stustoys]

Victory :2tsup:

Another job well done BT.

So whats next?? hehe

Stuart

[Ueee]

Nice work Bob:2tsup:

Um....just one thing though, have you given up in graduating the base?

[RayG]

Nice work BT, :2tsup: it's hard to see how you would get the profile much lower.... Mason Lock? ( I think there should be a patent on that.. :) )

Good to be able to tick the box on another project,

Regards
Ray

[Anorak Bob]

Nice work Bob:2tsup:

Um....just one thing though, have you given up in graduating the base?

Hello Ewan,

If I mounted the base as per the pretend setup photos, having graduations wouldn't make much sense. It would be easier to rely on the Mini-Sine bar clamped to the straight side of the base.

But if I fixed locating dowels in the underside of the base, that engage the table or longitudinal tee slots, then graduations would be sensible. The trick is how do I mark the graduations. Scribing tears the cast iron and leaves upstanding edges. Engraving would be the answer but I need to make up a mount for some sort of engraving spindle. I will make an appointment with Rod M to discuss the feasibilty of the engraving option.

Now, you blokes ask what's next. Well I've got a plane to catch up with.

BT

[Anorak Bob]

I made a little backstop (which awaits a plastic insert), a pair of 4140 tee nuts to fit the longitudinal slide's tee slot and scraped the hump out of the underside of the top section. Here's the finished article in place. For the additional vertical clearance it was worth the effort. One cam locks the base up solidly, the other three provide comfort. The backstop provides even more comfort.

The Centricator fits.

BT


235948

[RayG]

Hi BT,

Congratulations on completing a marathon project, beautiful stuff, :2tsup: good to see the centricator in use too, I admit to being curious about how you would use it... I think I can see it now! :)

Regards
Ray

[Anorak Bob]

Hi BT,

Congratulations on completing a marathon project, beautiful stuff, :2tsup: good to see the centricator in use too, I admit to being curious about how you would use it... I think I can see it now! :)

Regards
Ray

Thank you Ray and all the blokes who have provided advice and encouragement throughout the ten months this project has taken to complete. I have learned a bit about the accuracy of my machines in the process. The futility and frustration of chasing microns. Remember the tailstock on the lathe, the shimming, the indicator deflection. There has been a lot of sidetracking. A trip to the Tool Capital for an introduction to scraping......

That it works is the best result.

BT