an eccentric turning faceplate for the taig.

[peatoluser]

I've always wanted a keats type vee block for the peatol , but commercial castings are just too big. But while trawling the archives i came across a 'sliding block faceplate' made by Marlyn Hadley and posted by oldmechthings and decided to try and make something similar for the peatol. so thanks gentlemen for the inspiration and sharing.

first step was to make the faceplate. marked out a 3 & 1/2 inch circle on some 5/16 by 4 flat bar and roughly hacksawed and filed to shape. then cut down one of those nose blanks and welded it roughly central to the plate. (didn't realise you could buy them. paid more for a local engineering firm to make me some :'( ).

screw onto spindle and make swarf. had to move on cross slide to so as to cover face and the O.D. was a bugger to do.

next was the slides. I was using 1 1/2 wide flat bar for the centre , so marked of as best i could the setting lines for it, drilled and bolted to face plate , then done the same for the outside guides. i used 4mm bolts but 5mm clearance holes for some waggle room.

out with the hacksaw and file , back on the face plate and scim O.D. once more. remove the centre piece and measure the two outside guides. Halve the difference and this is how much the centre slide is out of true with the faceplate. refit centre , loosen screws and tap all three in which ever direction corrects it, re tighten scim and repeat. I finally got a 2 thou difference and then realised this stage is unnecessary as i haven't made the vee fixture yet :.

take out the centre piece and mill some slots in the faceplate

then thought of a modification and changed the centre bar for one with some overhang at either end. the vee block is just some BMS angle i bought thinking it was 90 degrees and could use it for some small angle plates. It isn't and has sat on the shelf mocking me for the past few months, but now i have a use for it! cut about 1 1/4 off it and tacked a small piece of scrap pipe to it.
chucked an off cut in the lathe and turned diameter true. made a clamp to bolt angle to this and faced off end

drilled and tapped centre bar for clamping bolts. also scibed 1 inch dia circle in centre and tapped 5mm. Make a setting washer from 1 inch bar 6mm hole about 1/4 thick. Bolt washer as best you can to fit circle, place vee against it and mark where the tube is .tap 5mm in centre of this tube . We need plenty of waggle room here.. I had to remake this bit as this hole interfered with the clamp hole. if i can make anything it sure is scrap :-[ . I've removed the washer in this photo

Refit bar to faceplate and screw onto lathe. Clamp a 1 dia. bar in vee block and then try and centre it , gentle taps with a small hammer - although at times i wanted to use a sledge hammer on the bugger ;

I settled for 0.003 TIR on the grounds i would be happy with that on a 3 jaw chuck.
all I've done is centre the vee on one dia, but we need the vee to be truly in line with the sliding member, if you get my drift. So, remove bar and refit washer making sure it is snug against the vee.

Now clamp a piece of ,say, 5/8 bar in the vee , move slide and centre this , trying not to disturb the washer. i.e. the vee should pivot on this . helps if you first get the for and aft readings from the slide the same before moving the vee.

go back and recheck with with the 1 inch bar that this setting hasn't shifted, well not by too much anyway.
Now its time to distorted all this accuracy. Weld the vee to the slide , and hacksaw off the tube and clean up.
we should have a nicely distorted base , so once again chuck a piece of bar, clean up the O.D., and clamp the vee to it. I also remade the clamp at this time. scim the base. once again I had to move the tool post to do this.

Not quite finished. reassemble on lathe , and again, centre up a piece of 1 inch dia. bar. this is going to be our reference dia. Remove and hacksaw the outer edges of the slide as close to the faceplate O.D. Rechuck and clean up O.D.

we now have a quick means of centering 1 dia bar. you can see why i changed the centre slider.
Doesit work?
turn O.D. of eccentric

offset and drill/ bore hole (its 0.150 inch offset in photo)

re centre using O.D. of faceplate and part off.

draw backs? I need to free off the slide a little to make setting the of-set easier, and now i suppose I'll have to try and build a triple expansion engine to justify making it ;D
Apologies for poor photos. cheap hand held camera. at least nobody can see my poor workmanship! I would ask for a decent one for Christmas, but apparently only my wife gets this privilege, i get what I'm given. anybody need spare socks, hankies etc?
happy swarf making, peter

 

[peatoluser]

An additional fixture for the above.
to produce a number of crank webs with identical hole centres I first bored out one hole in each web and also made a spigot from 1/2 bar with a 1/4 by 40 thread.
then I drilled and tapped a piece of flat bar to fit the centre slide and filed edge flush with edge of faceplate.
drilled and tapped this 1/4 by 40, loctited spigot into it and turned down to 3/8 dia. and drilled/tapped this 5mm.

Then used vernier and move slide correct amount and drilled clearance hole for boring

Then simply bored out 2nd hole in each web

It's a lot less fiddly than the usual method of trying to centre the second hole with a wobble bar, moving the spigot and tightening a clamp nearly all at the same time.
The problem with faceplate work is I never seem to have enough hands to set the job up properly.

Peter

 

[Deanofid]

That's pretty neat, Peter. I had missed your first post when the thread was new, but am well caught up now. Looks like a handy plate for offset/off center turning. Thanks for all the pics and words from another Taig guy. ;D

 

[Mo deller]

I thought at first this was a whole new post as I missed it before. Very interesting and I like the idea of clamping angle to a bar in the chuck. Must remember that.

Thanks for posting
Peter

 

[peatoluser]

Thanks for the comments Dean.
I've just clicked on your 'shop projects' site. That's some impressive machining, and well designed projects :bow:. I've been wondering about how to make a filing rest for the Taig and now I need wonder no more!
Those Taigs are great little machines. Wouldn't swap mine for a larger far eastern import.
yours
Peter

 

[compspecial]

This is an ingenious tool you have created Pete. it makes the mini lathe even more versatile, I can't think of a better device for machining crankshafts from solid, and ensuring you get the stroke of the crank set just right, so hard to do with rule and centre-punch.

 

[mhh]

That is one of the most ingenious ideas I have EVER and I repeat: EVER! seen! I just have to make one like that! (perhaps a bit larger, like.... 300mm ;D ;D) How about putting a 3jaw chuck on it?

 

[peatoluser]

Thanks for the comment's, but as I said at the start, I got the inspiration from a post by oldmechthings. The head scratching part was coming up with a method to produce a ' V block ' centred on the spindle axis with no milling machine.
If your lathe is big enough, and the head stock bearings robust enough, making something similar using a 3 jaw and a faceplate is the way to go.
It would be far better than the dodge of holding a small 3 jaw off-centre in larger 4 jaw.
yours

Peter