Threading cutter

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savarin

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Found this on youtube but cant make up my mind.
I thought it was clever but is it worth it or not.
Its in Italian but easy to understand
 

Latinrascalrg1

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Interesting. I guess if you had more then a couple of pieces needing the same thread pitch it would be a good way to knock them out, Maybe! :dunno:

Question.......I realize technically the video shows a guy "multi point threading" however isnt he basically single point threading meaning he would need to setup his lathe to cut the correct thread pitch as if he was doing a typical single point threading job in order to pull this off, Is this a Correct statement? If Not could you please explain? Thanks
 

mmcmdl

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He is single pointing . He's also adding distance to which he is threading . He also loses time on the length of the undercut he has to machine . A die head chaser is either floated or fed at a slower than pitch feedrate which allows the dies to set pitch , not the feedscrew .
 

Bob Kelly III

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i was thinking it would be a good idea to use up old busted dies .... but again why bother ?
however.... if he can make full threads in 2 passes that is a big leap forward !
so far I have discovered that single point threads take a hour to cut and a gillion passes ! ....and guys, that just isn't practical....... a die will cut the threads in one pass..... so what's the point in single point threads ?
Bob.....
 

darkzero

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You don't do this for a living , and never will if that's true ! :grin:
I don't do this for a living but it reminds of an interview I went to at an aerospace company. I never got to the machining part of the interview cause I turned down the job not wanting to work nightshift. But the machine shop manager was telling me how so many people wouldn't pass the machining test part cause, well he would often say, "thank you very much for coming in but we can just buy steel wool". :D

I haven't even came close to a 1/8th of a gazillion passes total on all the threads I've single pointed since I started this hobby & I single point often, I rarely use dies. :big grin:
 

BROCKWOOD

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It's Italian. It's this type of approach that brought Ferrari Automobili into this world. But, no, I'll either use the die as delivered or single point.
 

Bob Kelly III

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You don't do this for a living , and never will if that's true ! :grin:
why thank you for stating the obvious ! but the idea is sense there is mutable cutters on his threading tool sense he was clever enough to put a busted die back into action, couldn't the thread be cut in a single pass ? or at the most 2 ??????
Bob.....
 

mmcmdl

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. Let alone the error that could be picked up using the feed screw along with the multiple teeth , I sure wouldn't want to try this on anything other than plastic . Kinda the same principle as a scissor type knurler vs. a conventional knurling tool . We all love to make things out of dull tools , broken bits etc , but are they practical ? :dunno:
 

MontanaLon

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Seems like a lot of work to still have to take 4 passes to cut a complete thread in brass. Realistically, you should be able to cut a thread in any material the die is harder than in 1 pass without lead screw engagement and not have to reverse to keep your thread dial in the same spot.

But, even the most rigid lathe will never be as rigid as a die that hasn't been compromised by cutting it in pieces is. And a die can do it in as large a size as you need. I don't know what the largest die made is but I know I have used pipe threading dies in sizes up to 1.5" using a pipe threading machine which is basically a lathe that is meant to grip pipe and spin it roughly in a circular motion and give you a convenient place to rest the die stock handle as it cuts the thread. There is really nothing precision about it besides the die itself.
 

BGHansen

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Reminds me of thread milling with a specific insert vs. the single point style cutter. The specific styles do the job quicker, one or two spins around the boss or hole vs. running through the complete thread. Might be applicable if you were making a lot of an oddball like a 1/2"-18 thread, but would sure be a lot of work for just a onesie.

Bruce
 

Downunder Bob

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A lot of work for what is essentially single pint cutting, you still need to use the leadscrew for correct pitch, however the thread form will be more accurate as that is ground into the die.

If I needed to make a thread of such accuracy I would single point it leaving it slightly oversized then run a die or die nut over it.

One advantage is it could be used on a variety of shaft diameters with the same pitch.
 

higgite

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I can't say that I have single point threaded a ton of times, but I have done a few and only one time that I recall that I would I have been able to use his miracle threader. All other times there wasn't room for such a long relief "groove".

Since I don'ta speaka di Italiano, I'm assuming he cut up an otherwise useless die. Otherwise, he could have just used the original die to cut 100 threads while he was creating his creation. :dunno:

Tom
 

benmychree

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One reason that he could thread with fewer passes is the lead in angle on the throat of the chaser, it cuts a thinner chip than a single point tool depending on the angle of chamfer on that particular chaser. I have seen threading tools made in the same style, from back in the old days and have a few made by Pratt & Whitney. Threading does not have to be slow with fine cuts, I read of a method of cutting coarse threads, and used it for years to cut 1 1/4 - 7tpi threads on tractor disc axles, it could do a finishes thread in 5 or 7 passes, I forget which.
 

Bob Kelly III

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well, personally I think the idea has merit ! and it needs to be duplicated and used to find out the capabilities
so what if it only cuts one thread.... you have to have a set of dies to do all threads anyway, but on the lathe with a single point you don't ..so there is a big advantage to single point threading.....
but I am thinking it has possibilities in one area.. fewer passes... to ME that would be a big improvement at .005" per cut it takes a terribly long time to reach thread depth.... obviously if you don't take such a small bite you can get the job done much faster ! .... but I am just learning how to single point thread and I am not good at it...at all ! in fact..... it is giving me hell.... LOL... but I am confident I will eventually get it down pat.
I believe my biggest problem so far has been the thread cutter.... as many of you have so graciously pointed out...it needs to be a good quality and SHARP cutter........
...so that precludes me using my old burnt up dies as thread cutters as they are quite dull...( and untempered too boot )
.....
I love the idea of bringing old technology up to date with the technology we have today.... but the problem is if you know the machine good and it's capabilities, the old technology worked just fine...it doesn't NEED to be improved upon !
..... however there are instances that improvement is necessary...like the bull pin on my Logan 922 it needed modification in a big way ! because everytime I tried to put it in back gears I pulled the bull pin out too far and the entire spindle had to come out to put it back in !
one could contend that it was just operator error.... and I might agree, except that the 2 and 3 time I pulled the pin out too far I Knew what I was doing and the consequences of pulling that pin out too far and I pulled it out too far by mistake anyway..... so it was time to modify ! it was just an ill conceived arrangement, with no provisions at all if you happened to screw up....
.....
I don't have the material to make such a tool ...or I would just to test it out ! .... it could be a real boon to the threading capabilities of the Hobby lathe !.... just like the flip up single point cutter that makes backing out unnecessary !
.....it simply expands your capabilities.....
.....
Bob......
 

benmychree

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Why do so many folks have so much trouble/ time elapsed time threading? they are afraid to take a appropriatly thick chip ---- You should be able to take a chip the better part of 1/2 depth the first cut, given a lathe sufficiently rigid, not mini lathes, but something like a 9" south bend, cutting relatively fine threads, like say, maybe 20 tpi or so; Learning how to do it; push the envelope! If you are just practicing, a messed up thread is not the end of the world.
 

Bob Kelly III

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LOL.... well my first attempt at single point threading turned into a disaster ! I took 15 to 20 thow my first cut... the next cut was screwed up because the thread dial went by so fast that I missed the mark and subsequently split the thread I had started.....
so I slowed the machine down to 20 on the VFD...and tried it again..... made about 3 or 4 10 thow cuts and all was looking respectable and then I missed sync again and destroyed what I had !
so I put it in back gears and waited for the thread dial to come around and I still missed the mark !
by now I am more than frustrated with the whole affair, but I finally got a deep enough cut to call it a thread.... but there were balls of metal hanging off the threads and it was the nastiest thread I have ever seen !
so I changed the cutter ! got a real sharp one... that stayed sharp for about 5 passes then the threads started looking like the last one with metal fragments all over the threads....
out of desperation I asked for help here and the first thing was slow the machine down ! use a sharp tool and make your depth of cut only 5 thow
.... so I did that , that turned out a fairly decent thread....( which took over an hour !) but I stopped too soon and didn't get the depth I needed....
.... i've attempted to single point thread about 2 dozen times now....
taking what I have learned from you guys and friends and they are improving but they are far from good threads !
it is so easy to screw up and miss with that tiny thread dial it is un real ....
so yah pushing the limit is one method, but I am trying to learn to do it RIGHT ...then I will play with it and see what I can get away with !
it's not that I am afraid to take a 20 thow cut it's that I have been told "definitely do not do that ".....
and when you only have 1 of the 3 criteria that is right, bad cutter , doing the sequence wrong, and not engaging the half nut at the right time
you definitely are just rolling the dice as to weather you will be able to make a good thread to begin with !
the only thing I have going for me is the machine is set up correctly.....
and then there is the metal I am trying to thread.... it's the softest mild steel I have ever seen ! it likes to ball up and not cut.... even with my carbide cutters. it reminds me alot of copper ! which I find is very strange !yet it is a old rusty steel axle from a hand truck. ( which keeps getting shorter and shorter ! LOL) ( yes it went through the Ranch fire as well so it too is probably annealed ! )
....
Bob.........
 

savarin

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Bob, you may find some interesting tidbits amongst these.

and although this relates to metric threading its equally at home on an imperial lathe.
 

BGHansen

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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
 

Bob Kelly III

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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........
 

higgite

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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
 

Suzuki4evr

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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.
 

plunger

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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
 

Bob Kelly III

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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............
 

Bob Kelly III

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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.......




.....
 

savarin

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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.
 

Bob Kelly III

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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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