aligning the holes in the back of a chuck.

[savarin]

The backplate is turned to size, register turned to size, bolt holes marked using the transfer screws.
Now the hardest part.
The jarring from the intermittent turning has I think tightened it up really tight onto the spindle, I cant unscrew it.
The finish is so nice that I dont want to mar it so I think two thin blocks of wood clamped with a heavy G clamp to the disk then hammer the g clamp whilst the spindle is locked will hopefully do the trick.

 

[savarin]

I had to drill a small dimple into the register part to apply a hammer and punch to break the fit. Just a couple of clouts and off it unscrewed.
This pic was supposed to have been posted on the last post.


The transfer screws worked, holes drilled, chuck mounted.


TIR on back plate is zero on face and dia, well, the needle quivers just, too small to read.
Remove and replace 6 times and still the same reading. I feel good about this.
The chuck dia reads max 0.003" runout
Is this too much?
I drilled the bolt holes to just a tad under the 8mm its supposed to be. Do you think if I drill them out to a tad over 8mm I can knudge the chuck to zero runout?
I know its a 4 jaw and that will be taken care of when setting up, I'm just curious.
It took some time to finish this but overall I'm very pleased with the outcome.

 

[JimDawson]

Nice job!

I think 0.003 is just fine for the OD of the chuck body. I actually took a cut on on the OD of mine to get it to run true, after getting everything else in alignment. My 4 jaw does not have a backplate.