Screwcutting is not mentioned much on this forum, so I thought I'd give myself a bit of a challenge, as I'm a precision engineer as opposed to a common artisan, and also bereft of a BSc. in treacle bending or whatever passes for a degree these days.
Here is the Brit reverser screw in stainless steel, left hand ACME thread form (or pretty close!), 1mm pitch. The nut is PB1, screwcut in the lathe also. It could have been done as a two start, but I thought I'd better keep it simple. A good day's work! JB
The finished item mounted in the lifting link
Closer look at the ACME form as specified for the original loco.
The screwcutting tool, 1/8" square. One thou at a time, lathe running backwards.....
Well done JB. I like it! And it’s nice to see more photographs of the ‘progress’. I’ve also been doing a bit of screwcutting 'off the leadscrew' today, but only simple standard thread form. I made myself a ‘Mandrel Handle’ at the weekend for todays work. I found it very useful to turn by hand to screwcut up to a shoulder. Did you turn yours by hand or machine?
Hello J.B., seeing that cracking piece of work brings back the memory of a task we were set at training school app/40 years ago...we had to make a jig for setting and sharpening ''Hand Saws''...there were four 5/8 by 24'' long rods of different pitch acme threads complete with nuts...I wont go in to telling any more...other than it was a real b£%%^& of a job...so well done ;D All the best for now, John.
Hi Chris and John. My machine doesn't have a clutch, so when cutting up to shoulders I set a stop on the bed and watch that. I stop the motor just short of it and inch the chuck by hand for the remaining distance. By the way, there will be a two week break in Brit Progress as I'm off to my bateau in France for some wine and cheese. Can't wait to get back to the Brit! JB