Update:
Yesterday I mounted my 10" 3-jaw chuck, which was an interesting exercise. The register was just outside of the range of the largest mic I have, so I used a tape measure and got close. I then took off .001" at a time, test fitting the chuck after each cut.
Once I got it to the point that it was a tight fit, I removed the backing plate from the lathe and marked out the 3 bolt holes to fasten the chuck. To do this I made some transfer punch screws out of some M12x1.75 bolts. First I turned a 60* point and then filed 2 flats to allow them to be screwed in with long nose pliers. Next they were cut to length. I got all three made from one bolt.
I read somewhere that the holes should be 1.5mm larger than the bolt size, so I drilled 13.5mm holes. Once this was done I threw the backing plate into the freezer, along with my lunch for tomorrow! Whilst the backing plate fits with a couple of gentle taps, cooling it down gave enough shrinkage that I could easily adjust its position to line the holes up. Once done, I put in the 3 bolts but didn't tighten them until both the backing plate and the chuck were at room temp.
Here are the transfer punch screws. In the last pic you can see one about to be screwed in and the other 2 in place.
Holes being drilled.
Chilling out!
All finished!
Edited to fix a typo
Yesterday I mounted my 10" 3-jaw chuck, which was an interesting exercise. The register was just outside of the range of the largest mic I have, so I used a tape measure and got close. I then took off .001" at a time, test fitting the chuck after each cut.
Once I got it to the point that it was a tight fit, I removed the backing plate from the lathe and marked out the 3 bolt holes to fasten the chuck. To do this I made some transfer punch screws out of some M12x1.75 bolts. First I turned a 60* point and then filed 2 flats to allow them to be screwed in with long nose pliers. Next they were cut to length. I got all three made from one bolt.
I read somewhere that the holes should be 1.5mm larger than the bolt size, so I drilled 13.5mm holes. Once this was done I threw the backing plate into the freezer, along with my lunch for tomorrow! Whilst the backing plate fits with a couple of gentle taps, cooling it down gave enough shrinkage that I could easily adjust its position to line the holes up. Once done, I put in the 3 bolts but didn't tighten them until both the backing plate and the chuck were at room temp.
Here are the transfer punch screws. In the last pic you can see one about to be screwed in and the other 2 in place.
Holes being drilled.
Chilling out!
All finished!
Edited to fix a typo
Hunting American dentists since 2015.