Hello,
I recently acquired an old boley size 2 lathe from perhaps the 1950s. This is a pretty rare model as far as I can tell, with only very limited information available online. The lathe is in pretty good shape, but the chuck is not true (though the spindle and mounting is). It's a 65 mm chuck, and the manufacturer no longer makes these. I decided to go for an 80mm chuck and to machine my own holder for the chuck. Everything was going pretty well, until I tried to thread the chuck mounting part. The threads I measured out at m20 x 2.3 mm (very close to 11 TPI). Needless to say, this is about as non-standard a thread as I can find. The angle of the thread is such that when I measure the inside of the old chuck I get a measurement of 16.5 mm. The outside of the existing threads is 19.96, so I'm pretty sure this is some variant of M20. M20x2.5 and M20 x 2.0 are standard, but neither is close enough to fit (even though I only need about 4 threads. Anyhow, I'm stuck and out of ideas. Boley often mixed metric and standard and seems to have had a lot of custom threads. One example: The collets on this (which I do not own) have a thread of something like 8.2 x 0.8mm... Any ideas or advice would be very much appreciated. I can post pictures if it would help.
I recently acquired an old boley size 2 lathe from perhaps the 1950s. This is a pretty rare model as far as I can tell, with only very limited information available online. The lathe is in pretty good shape, but the chuck is not true (though the spindle and mounting is). It's a 65 mm chuck, and the manufacturer no longer makes these. I decided to go for an 80mm chuck and to machine my own holder for the chuck. Everything was going pretty well, until I tried to thread the chuck mounting part. The threads I measured out at m20 x 2.3 mm (very close to 11 TPI). Needless to say, this is about as non-standard a thread as I can find. The angle of the thread is such that when I measure the inside of the old chuck I get a measurement of 16.5 mm. The outside of the existing threads is 19.96, so I'm pretty sure this is some variant of M20. M20x2.5 and M20 x 2.0 are standard, but neither is close enough to fit (even though I only need about 4 threads. Anyhow, I'm stuck and out of ideas. Boley often mixed metric and standard and seems to have had a lot of custom threads. One example: The collets on this (which I do not own) have a thread of something like 8.2 x 0.8mm... Any ideas or advice would be very much appreciated. I can post pictures if it would help.
Last edited:
We need pictures.