Fitting a new lathe chuck

[7mag]

A guy asked me a few months ago to help him fit a new chuck to his lathe and I sent him some pics of a job I did on a South Bend 9. This is what I came up with. I got a new chuck and backplate from CDCO.

 

[7mag]

With the backplate fitted to the spindle, I use a 1/4" steel rod in the 1/4" hole I drilled earlier and remove the backplate and check the fit with blueing to make sure the shoulder and backplate mate properly.
This should insure that you can remove the chuck later and put it back on and it should be the same.