Thread: zeroing in the 4 jaw

What if you drilled and reamed the stock then cut it in half. Turn a stub parallel mandrel with the last one and a half to two millimetre section fractionally larger to create a press fit then drill and tap the end of the stub mandrel for a clamping bolt. Do most of the machining with the clamp bolt in place then remove the bolt and gently face the last bit.

Phil

Dean,
I was actually indicating a bit closer to the chuck than shown in the photo, but the jaws wouldn't allow me to read off the turned section that was being held in the chuck. Now that I've reversed the jaws I should be able to indicate off this part of the workpiece.

Phil,
I hadn't thought of a stub mandrel. I've got some 16mm MS I could use. I'll mull it over.

If you are trying to true up the od with what is in the chuck then you need to zero from the chucked section. Good luck. I have done a similar thing but with cast pieces off another spindle. My grinder had pressed plate (sheet) flanges and relied almost entirely on luck. I am going to ditch it and get a decent one.

Dean

Hi Chris,
I have a set of reverse jaws in the shed. They don't fit any of my chucks, but look to be about the same size as my 130 jaws. If you want to post or pm me the dimensions of the jaws you may get lucky.....

Thanks Ewan, I'll measure the jaws in my chuck tomorrow and get back to you.
Chris