Fitting to a backing plate

[DavidR8]

So my new 4-jaw arrived today
It has a semi-finished backing plate, threaded and drilled for the chuck. All that remains is to turn the register down to fit.

I'm going to assume that it would be prudent to do a a light facing cut to ensure that the backing plate is square to my spindle?

 

[darkzero]

Yes, right you are.

 

[DavidR8]

Yes!
(David does a happy dance as he might be starting to figure some things out!)
Thanks @darkzero

 

[darkzero]

I'm sure you're a hampy camper right now. Always a happy moment getting a new chuck and after you get it set up. Congrats!

 

[Bob Korves]

It may go without saying, but mark the back plate and spindle after machining it true if it is a D series or other style that can be indexed in different clock positions. Screw on chuck, no issue. You need your newly achieved accuracy to be repeatable the next time you mount it. Every spindle should have an index mark on it for clocking tools in their most accurate position, and the dedicated tools as well...

 

[DavidR8]

Thanks @Bob Korves, it is a screw-on chuck so no indexing there.
Once I get it all together I will mark index the back plate to the chuck though.

One question: should I put the plate on backwards and take a light facing cut off the snout that registers against the spindle shoulder?

(Not sure if my terminology is correct there...)


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[mmcmdl]

I wouldn't Dave . I would assume it was machined square and concentric in one operation with the threads . ( note I said assumed ) .

 

[Bob Korves]

One question: should I put the plate on backwards and take a light facing cut off the snout that registers against the spindle shoulder?

With a screw on chuck, the adapter will only fit in one position. Mount it to the spindle, snug it down, and then face it flat. It is then true to the spindle of that lathe. If the chuck does not turn true when mounted to the mounted and turned adapter, it can also be machined, but that is a whole different job that is more fussy. Ask for more help if you end up with that issue.

 

[DavidR8]

I wouldn't Dave . I would assume it was machined square and concentric in one operation with the threads . ( note I said assumed ) .

Thanks Dave, I was thinking about that potential.
Also wondering how I’d make it square if there’s the potential for the face of it not to be square.

I’ll set up my DTI and see what’s going on before I do anything.


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[BtoVin83]

IMHO Make sure the backing plate is well seated on the spindle. A light facing cut to true the face and turn the register to fit your chuck. Truing the face takes the wobble out of the chuck and turning the register makes the chuck run concentric.