Simple chuck/faceplate threaded mount for mill table

[Peter Cook 6Participant @petercook6]

I have a small Taig lathe with an ER headstock that has an M22 x 1.5 thread for mounting chucks and faceplates. I have been looking at ways of mounting the chucks and face plates on the mill table – mainly to use the PCD function on the DRO. The Taig doesn’t have screw cutting capability, so I have been looking for a simple way of getting an M22x1.5 male thread that I could mount on the mill bed.

I came across some M22 x 1.5 hydraulic blanking plugs on E-bay, so I bought a couple to try out. With an M6 hole drilled through and bolted to a T nut they work perfectly for the job.

A quick trawl suggest similar blanking plugs are available in 3/4 x16 which matches the standard Taig Headstock, M14 x 1 and M12 x 1 which would suit various flavours of Unimat. Other sizes to suit your lathe may be available!

 

[Julie AnnParticipant @julieann]

I am mystified; surely the whole point of a PCD function is that one just mounts the plate in a fixed postion on the table. Then find the centre, enter number of holes and PCD into the DRO, and the DRO then points to the correct position for each hole.

There is no need for the work to be mounted in a chuck, on a faceplate, or rotated; just clamped to the table, like this:

Julie

[JasonBModerator @jasonb]

If you want to put a PCD pattern into small parts then a chuck or even a collet can be a lot easier as you may not have room to get clamps into place. Also there may be the need to go back and do other ops so keeping things in the chuck keeps it all concentric.

Emco offered such an item for the U3 as I have one and made good use of it not only to mount chucks but as it also allowed the drill/mill column to be mounted on the cross slide you could mill or drill work in teh spindle.

I also regularaly hold work on the mill using a chuck, typical uses may be to mill the spokes for a flywheel where I want the cutter to get close to the edge without the collet nut hitting a clamping plate.

[JasonBModerator @jasonb]

Not much room to get clamps onto this for example

[Nigel Graham 2Participant @nigelgraham2]

As Julie points out if use a PCD function you should not need hold the work in the chuck, but if you do I would point out one potential problem if you also try more than simply drilling pitch-circles of holes – for example milling flats on the periphery..

The action of the cutter and feed pressure will try to rotate the work anti-clockwise, i.e. to unscrew the chuck from its mounting.

One way round that is to arrange a simple stop against a chuck-jaw, on the anticlockwise side of the jaw.

 

[Michael GilliganParticipant @michaelgilligan61133]

A very useful “make-from” Peter … well-found.

MichaelG.

[Peter Cook 6Participant @petercook6]

Julie, as Jason said, there are (at least) two reasons. One is when the part is difficult to clamp because of size or shape, the second is when you want to do further turning on the item after drilling. This (a current work in progress) is an example that illustrates both issues.

Item is brass, raw stock is 30mm diameter so too big for my  ER collets in the lathe. Finished diameter of the disk is 22mm, with three 2.5mm partial holes round the periphery. Rod is 8mm. Whole thing is about 15mm tall. It’s not untypical of the size of things I make.

Turn the 8mm part down on the main stock. I don’t want to try drilling those partial holes, so I will ( not finished yet) transfer the part in the chuck to the mill. Drill the three holes, then back on the lathe to turn down to the finished diameter as an interrupted cut when I reach the holes.

It can then be flipped round, the 8mm part held in a collet and the spare stock parted off.

The part would be a bit of a pig to clamp anyway because of its size. But I need to keep it all concentric as possible. I’m sure with some creativity I could have done it another way. Tool post drill and indexing system for the lathe spindle come to mind, but considerably more expensive than the <£4 delivered the blanking plug cost me.

John, understood about the unscrewing issue. Sherline suggest, and make a gadget for on these small chucks, putting a tommy bar in a hole in the body (not the scroll!) and clamp that to prevent rotation. A simple unit to do so is on the round tuit list.

[JasonBModerator @jasonb]

Or you can do what I show in the flywheel picture, rest the chuck on some packing and clamp to the mill table. This is what I do if the work is in one of the flange mount chucks which are not threaded.

[Nigel Graham 2Participant @nigelgraham2]

Peter –

Unless I’ve missed some intermediate post it was a Nigel not a John who warned of the potential unscrewing problem! 🙂

Other than than the method you describe is fine. My own chuck-holder is a commercial item to hold Myford fittings, but the same principle. I’ve also one I made aeons ago for my EW lathe chucks, to hold them on a small rotary-table I was given.

[Peter Cook 6Participant @petercook6]

Sorry Nigel finger trouble or brain fade!!!

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