All discussion about lathes including but not limited to: South Bend, Hardinge, Logan, Monarch, Clausing and other HSM lathes, including imports
Well in a way, cutting LH Outside threads is easier because of starting from the shoulder and working backward. Then again, not everyone has tools ground or holders for that. This instant reverse biz has more to do with reading the thread dial and even there, there is more. Those particular Enco/Jets have this lever which jockeys the motor and releases the tension. It is on a cam. Mine is adjusted so that it will turn but not at the same speed or torque as fully engaged. I'm playing with the fact that it has a very wide belt, instead of two matched ones at that point. This doesn't disrupt the timing or anything further down the gear train. It does allow the spindle to turn very slowly and even start a cut while I increase the cam leverage.
A bit more. Thread dials. All so many wonderous lathes which built so much had threaded spindles. Most if not many, had 8 divisions or more... I stop there about dial divisions and lathe charts...it is so already there. What they didn't have was reverse at the apron. The machinist had to make a conscious decision to reverse the spindle of an 80lb chuck in order to run everything backwards.
These Jet, Encos and many others were made by the same company in Taiwan. UK lathes lists the "Lantain" lathe brand. Many of the different brands and models are really Lantain. Lots of info / pics and they sell manuals for them.
I solve the chuck install problem. It seems the chuck goes on in so precise a position, it has to be mounted DEAD center of the plate, and then once its pulled tight, it goes on and off with no problem. The more I learn about this lathe, the more things make sense. Its like this lathe has none of the normal wear that makes things go easier. Even after soda blasting it, all the corners are still sharp, like its right out of the mold, and grinding process. I'm starting to believe the guy that bought this thing new tried to learn to use it, and just gave up at some point. Left it sitting covered in dried grease for 40 years. I think the problem I'm having with the QCGB is because its never been shifted from the C gear range. It just set there running the whole time in the same range.
I misspelled Lantaine. My chuck is original to the lathe also. The backing plate has the spiral thread marks of the deepest inside thread. It also fits very snugly. I think you have a good machine there. After all these years, there is some shop cred.
What I meant was the radial register. Part of the back plate of the chuck is usually unthreaded before it goes to the largest diameter of the nose threads. In these cases; they were ... heck probably ... they got it dang close and screwed the chuck on. Cain't say from here. Sometimes we get lucky. We know that over at P. M. they don't even discuss this "junk". There are reasons for that but as screwy as some of these were, some very good ones were made.
NO, no, no! This wasn't forced. It was the very tip of sharp threading tool ! Very snug and needs to be started the same way from the collar of the backplate. It has been many years and I haven't been on any "Asian Lathes" sites to discuss or know this was common but there it is. I can imagine the collar being started in just the wrong position, causing binding or wear.