I just scored a nice Perton watchmaker's lathe, for what I think is a fair price ($200). The bed, headstock and tailstock are stamped with matching serial numbers, CR 337. Plus it has the tipover tee-rest, and the nickel plating seems about 95% intact. I got it from the local jeweler's shop - they display lots of bric-a-brac and knick-knacks having to do with jewelrymaking and the local history with copper mining, and I noticed this lathe on a wall shelf - long story short, I have the lathe and they have $200. The owner said he has had it for over 20 years and never used it. It came with a motor, all on a Borel stand. I just overhauled it last night and it seems to turn smoothly - I don't want to run it with a motor until I get a couple of questions answered.
Can a Perton owner please tell me what the thread diameter and pitch is of the benchmounting bolt-hole, underneath the lathe bed? I think the diameter is 5/16", but 5/16-18 doesn't work and neither does 5/16-24......so I suspect the real thread pitch in question is probably 5/16-20, but I could be wrong. I read somewhere last night that if you ever think a bolt hole must be 5/16-20, it's actually metric M8-1.25. Well, I don't think that's the case on this Perton lathe because (1) it's American, and (2) everything else on the lathe conforms to SAE thread pitches, not metric pitches.
I have other question, but I want to start with the above one. Thanks.
Can a Perton owner please tell me what the thread diameter and pitch is of the benchmounting bolt-hole, underneath the lathe bed? I think the diameter is 5/16", but 5/16-18 doesn't work and neither does 5/16-24......so I suspect the real thread pitch in question is probably 5/16-20, but I could be wrong. I read somewhere last night that if you ever think a bolt hole must be 5/16-20, it's actually metric M8-1.25. Well, I don't think that's the case on this Perton lathe because (1) it's American, and (2) everything else on the lathe conforms to SAE thread pitches, not metric pitches.
I have other question, but I want to start with the above one. Thanks.