Facing bar ends parallel on the lathe.

Thanks for replies. I understand that milling is the 'natural' technique for making the ends of a bar parallel, but for various reasons it's not an option here.

Several good ideas for doing it on the lathe though - I'll experiment. I think Martin's / Gray's suggestions of turning between centres will be the first experiment - it's a technique I've never used, so it'll be fun and seems to be guaranteed to work - provided the lathe's set up correctly of course!

Good to hear that 0.03mm isn't too bad given that it's a Chinese lathe/chuck. The chap I'm working with has suggested referencing off the chuck face using parallels, which is another avenue to explore. I guess that's going to be more accurate than referencing from the flats on the jaws.

Hopper - I dug out the face plate, there was a weird contrivance bolted to it, what's that I thought, then it came to me - it's the gizmo! That's from a while back!

Robin.

" a weird contrivance bolted to it"

Hard to tell without a photo but could be a Keats angle plate for holding round parts on a faceplate.

Paul

Why take a guess, put a Dti on the chuck face and see what it runs like, no point in using that if it's too far off, same as knocking it back against the chuck jaws if they are off.

Also once you pull the parallels out or before turning if leaving them safely secured ion place put a dit on the back face of the work to check runout, a bit like this but you will need the rear one on the cross slide so you can move it out the way of the jaws

Edited By JasonB on 10/08/2020 07:07:37

A lazy but wasteful way may be to just chuck up a length, face the free end and then a deep groove near the chuck end just deep enough for whatever fixings are needed and cleaned up... then off the lathe finish cutting through with a saw, back on the lathe and bore out a central depression below your clean face.

pgk

That magnetic test indicator mount looks very handy Jason did you buy it or make it up yourself.

Ron

Which one they are both magnetic? Though they both came from ARC

Ebay cheapie, I've had one for 10 years, although I presume Jason has put a nice DTI on it

Yes nice ARC DTIs

.

Robin

Posting on your ‘faceplate’ thread this morning reminded me to mention this ...

For best results when turning between centres, you will [obviously ?] need to switch the workpiece end-for-end, rather than changing tools and saddle position. ... You want both faces to end-up either flat or very slightly concave.

MichaelG.

This is true.

I'll add that for supreme accuracy, be sure that the heastock centre is running true, and if it isn't, then give it a skim in position to make it so.

Martin.