# Making a chuck backplate



## Suzuki4evr (Dec 21, 2017)

A while ago I bought a 4 jaw 250mm(9.842 inches) scroll chuck and I needed to make a backplate for it. I am not buying something if I can make it and have time to do so. Sorry but all measurements will be metric,because where I am from, that is what we mostly work with all though we use imperial sizes as well.

I started by facing and squaring the cast iron stock to about 2mm before final OD. This side would be the side facing the lathe spindle.






I then senter drilled it and drilled it with the biggest drill I have (48mm) and bored it to just under the size of the spindle nose cone size.






Then I machined a recess to 170mm, this is the OD size of where the chuck would seat on the backblate,protruding about 1.5mm. I then machined the taper at 7`7'30" that is 7.125 degrees. Sorry I forgot to take a picture of that process.


I then started to mark out and drilled the holes for the cap screws that will bolt the backplate to the chuck and tapped it M12. Using a 20mm slot drill,I counter sunk the holes to depth for the allen cap screws.






I did the same procedure for the 4 lock bolts, except for the countersinking, that would clamp the backplate to the spindle. I must still make up new bolts for this chuck, but being to exited to use my new chuck,I borrowed the 3jaw chucks bolts for now. Here you can see the taper machined for the spindle nose.








Now that that is done, I can bolt the backplate to the spindle of the lathe and do the rest of the machining. And in that way I am sure everything is perpendicular and true. Firstly I machined the OD to size and  machined the part that faced the chuck to protrude 5mm and snugly fitting the recess in the chuck. Almost done. Faced the landing where the chuck must seat with a very fine cut.






Took the backplate off,bolted it to the chuck and fitted it to the lathe and Bob's your uncle  you've got a brand new lathe chuck and backplate




Always fun and thanks for watching.


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## barnett (Dec 21, 2017)

Nice job !


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## RandyM (Dec 21, 2017)

Yup,


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## Bob Korves (Dec 21, 2017)

Suzuki4evr said:


> Sorry but all measurements will be metric,because where I am from, that is what we mostly work with


Nice work.  Metric is no problem, we just look at the other side of the ruler...


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## Suzuki4evr (Dec 21, 2017)




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