Excuse me but what is a cats cradle in respect to turning on a lathe. I just don't understand what it is as the only cats cradle I know is a piece of string loop round my fingers in my youth.

David

People call them by different names, I think this is what is being asked about. I have one for my Pultra but have never needed to use it.

**LINK**

Phil

Edit

Yes I was thinking of the wrong thing PGK, similar principle but you are right I believe.

A bit more info here.

http://www.chaski.org/homemachinist/viewtopic.php?t=77698

Edited By Phil P on 14/05/2020 08:37:59

Edited By Phil P on 14/05/2020 08:41:32

Edited By Phil P on 14/05/2020 08:42:09

There are folk on here more qualified with experience than myself. But if wanting to check how thw tailstock quill affcets things I'd have thought some round stock in the tailstock chuck with DTI on bed and run the quill in and out. You still have the issue of flex in that stock and whether the dti stays centred. Or mount the DTI in the chuck and run it along the bed with the quill?
For the 4-jaw you're centring it manually so what may affect it is angulation within the chuck jaws or body. Either centre a decent diameter ground or turned bar and check DTI close to chuck and away. Or just check the chuck face is true and assume/hope the jaws will be too?

pgk

Paul Lousick posted this image about a year ago:

http://www.model-engineer.co.uk/forums/postings.asp?th=140764

It's possible to mount one on an irregular workpiece for a steady to run on, rather than holding it in a chuck.

They are somewhat hazardous so a screen/guard is certainly advised.

Neil

Edited By Neil Wyatt on 14/05/2020 10:54:53

That's it. Seems he calls it a spider. Also called a catshead by others. You can also use it to hold long square or hex bar with a fixed steady.

we always called them a spider useed when turning long hexagone or square bar just set them on the bar ajust to run true by the screws then use steady also used on backend of head stock to stop long bars from whipping

I'm not entirely sure i understand that post. I guess the raw square stock won't fit inside your headstock so any set-up is bound to be tedious. I'd probably cut a short length that can be held in the 4-jaw without 'drooping' and then use the simple trick of 4 bits of flat scrap and an elastic band so one can indicate on the inside surfaces (quicker) to get the 4-jaw pretty well centred. Then do the same thing with your cats cradle in the fixed steady wth that trial piece of spare stock before setting things up at their relative distances and finalising indication at the ends and middle with the workpiece and facing it's ends.

pgk

Every time I post it doubles up, and some other people have the same problem 

Edited By old mart on 15/05/2020 16:35:06