G'day Mike:
Very interesting but the M feedscrew I had to duplicate was examined under an optical comparator and there was no doubt the thread of the original 1892 part was a 45ยบ buttress thread. The depth of the thread is only 0.007" so the lathe setup is crucial. I will have to check the later threads but the one I did had a buttress thread and the halfnut was likewise set. It would make sense to have a buttress thread at 100 threads per inch with the 'strong' direction pushing the halfnut and carriage to the right. At 100 tpi the thread height for any thread should be uncomfortably small. On yours was the thread a 'normal' V thread that was not directional? What was the depth of thread? It is good to see you on the list. I hope all is well with you. My wife and I have a planned vacation down under. Off list tell me what sights the locals would recommend? Regards, Al _______________________________________________ Phono-L mailing list http://phono-l.oldcrank.org
