Threading cutter

If you are missing the mark, try shutting off the lathe and moving the carriage manually (longitudinally) until you see the mark. Engage the half nuts and turn the power on.

Bruce
 
Thanks Bruce..... I'll try that... I usually set up threading so I have ample room on either side...i should be able to get far enough to align that mark on the thread dial again ! ..... that's a good idea thank you !
Bob........
 
Speaking of number of passes, I noticed the the guy in the video didn't test the thread with a nut or thread gauge to verify that a finished thread was accomplished in 4 passes. And with no spring passes. For the sake of science, and the furtherment of machinedom in general, I think someone besides me should try it on at least three different sizes of threads and report their findings.

Tom
 
Geometric diehead chaser . I can't see the point of it . :dunno:
Neither can I. Looks like way too much work for one threading cutter,but as long as our Italian friend enjoyed himself making it,good for him.
 
Might lend itself to the teeth of a rigid pipe die. That would be a far simpler tool to make. I dont own any thread dies so have to single point everything ,.In brass Im brave and take deep cuts but in steel I have often wondered how many passes are required in general
 
LOL....I think I may have found a reason I've been having trouble hitting the mark on the thread dial..... it's not the eyesight ( though that is questionable) it was the slop in the leadscrew !
I made a larger thread dial to see if that would help me "find the mark" easier made it about 2 1/4" in diam. i figure if I can't hit that mark I better give up the idea of threading completely ! LOL.....
anyway while I was taking the old tiny thread dial off there I noticed that I could move the lead screw a good 3/16" ...the slop it had was rather substantial !.... got to looking at it and all I had to do was loosen the collar next to the QCGB and tap it in a bit and then re tighten it....
now there is no slop in it at all. <GRIN> and I bet you that that was contributing to the easiness of it being locked down with the half nut in the wrong tooth !.....
i did several dry runs seeing if it reacted differently and I think there is a vast improvement in the way it locks in with the half nut.
my back was starting to hurt so I gave it up , but i am itching to try it now... I may have cured my threading problems today ! ....we shall see !
it's funny how a person can overlook the obvious ! ... with that lead screw slop obviously it would affect the thread dial and half nut engagement.
...although there wasn't enough slop to reach another tooth in the half nut it would have been very close.... enough to land halfway between the teeth at odd intervals and split the threads..... I feel confident that I found one of my major problems ! ....<GRIN>
.....we'll see what happens on the next single point threading session ! HAHHAHAHA
.....
Bob............
 
welp, i went out there and cut my first single point thread... and the nut actually fit it ! loose but it did go on !
so now it's just refine what I know that works i think....
although it is a useable thread ( 1/2" x 13tpi ) it is loose, but I've seen store bought threaded rod as loose as this one, ....so I am calling it useable !
..... but it's rough.... if I look real close I can see there the threads were tearing a bit so I was probably too aggressive on my depth of cut
though near the bottom of the thread I did take shallower cuts around the 2 thow to 3 thow range... but by then the damage of the 2nd and 3rd cut had already been done there I took about 10 thow cuts to get the thing underway....( impatient!)
and although it only took me about 10 minutes to a max of 15 minutes to set up the machine AND cut the threads i think I should have taken a bit less aggressive approach and that should have produced better results ! ( learning is a good thing ! )
all totaled I am guessing at about 20 total passes.... so you know it had to be really aggressive..... but the thread quality was less than desirable !
.....
so Now I am thinking that 5 thow cuts Max when cutting threads is the best way to go.... even if that triples the time it takes to get the job done
.....
the tightening of the slop out of the lead screw helped a bunch.... i didn't miss my mark even once, and the larger thread dial helps as well....
so I am calling tonight a success ! LOL....

Bob.......




.....
 
excellent news.
Get that tool bit really sharp and honed.
Re-bar steel is horrible to turn and thread, not saying thats what you have but very sharp HSS tools will do a fair job.
 
I ground a carbide cutter into a 60 deg point and then honed it.... it's the sharpest thing I ever tried to cut with before LOL....
( but probably still inadequate ! )....
what I am turning was an axle of a hand truck that went through the Ranch fire old and rusty and probably anealed too....
I have a few long bolts without threads I will try to put some on next ! LOL....
i need to invest in some threading tools !( HSS ! or carbide ! )
Bob........
 
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