Just because I've almost joined the club doesn't mean that I've memorised all the rules yet :-(
I had got it into my head that the leadscrew was 10tpi instead of 8... that would have given only one right way and one wrong way to engage the clutch at the start of each cut, that would have been manageable with patience. Still possible to do if you retract the tool, then reverse the entire lathe to get back to the start of the thread. That would mean fitting a reversing switch to the power supply and being very patient or putting a handle on the back of the mandrel and reversing it with an Armstrong drive.
Chuckle..the first time you set up a HLV-H for threading..after threading on any other machine..it will set you aback...you will go..WTF????
The lead screw is controlled by the gearbox/aux gears, but it has a lever for forwards and reverse. A rod below the leadscrew holds a pair of adjustable stops and you set the left one to pull the lever into neutral at the end of your thread, and the same with the right..at the free space before the start of your thread. The tool holder has a lever which retracts the tool bit about .5 or so. You touch the tool to the part, zero your compound dial, then pull the feed screw lever. The carraige travels to the left stop, where it kicks the feed screw into neutral. You pull the lever on the compound and retract the bit. Then pull the lever so the leadscrew reverse and pushs the carraige away from the headstock until it hits the right stop, which kicks it into neutral.
You crank the infeed a proper amount, pull the compound so it returns the tool to cutting position, hit the feed screw lever so it makes the cut..it hits the end stop, putting it into neutral, you retract the tool, reverse the carraige, dial in feed, put the tool back into cutting, hit the lever..and repeat as necessary.
You can thread to a shoulder at 500 rpm, faster actually is quicker to cut threads, because of the carriage return time. Getting into a rythem is easy, the longest time involved is the actual thread cutting. Getting into a rythem can be an issue though if ones not careful and paying attention.
in fact..its so easy that one sometimes forgets to stop and measure...sigh..Ive quickly made some perfect threads that were way way undersized. Chuckle. The smooth transition and repetative hand motions and the way the thread develops can be hypnotic..
You never open and close the half nut when threading. On the few times Ive done it..particularly after recently doing conventional lathe threading..it is however easy to pick up the thread. One simply has to adjust the fine adjustments on the end stops...not so good through if you are threading to a shoulder..thats a bit harder to get right after you have opened the half nuts because of a brain fart.
Gunner
Political Correctness
A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.
Yeah, got all that... I was ruminating on the specific problem of convincing a Hardinge that it knew how to cut a 5tpi thread without double starts :-)
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