Small Threading Tool

[Ken_Shea]

Rick,
Not sure what your intent is in your reply, but it sounds argumentative, if not essentially calling me a liar. It is these pompous replies to post that so turn people off, I joined for enjoyment and to learn and perhaps share.
Not to be whacked in my first couple of post. I bet you are a member of PM aren't you.

Who are you trying to kid with words like - "eliminated", "Every piece, EVERY TIME, " programmed to cut a
perfect thread. "

That's laughable, and what will you say next, ZERO rejects?

Any way, who needs mean spirited criticism, life is too short.

 

[rake60]

NO!
I wasn't saying that!

I'm getting into trouble here tonight!
My point is threading is a hands on art.
There is NO perfect answer.
It is a skilled craft that any determined home machinist can master.
I apologize if it was taken as an attack!!!!!!

Of course there were rejects in the shop I worked for when I first got
into the marching business. But those parts were REJECTED!
At that time in 1979 they were worth about 12 cents a pound.


Rick

 

[lugnut]

Ken, you’re out of line here. What Rick is trying to say is, Have you ever gone to Ace hardware and bought ½ nc nut that would not fit ANY !/2 nc bolt in the store? OF coarse not, wake up. Now if you insist in making your own with your own method or what ever------Yes your going to screw up some times, so what??? Get over it and make a new one. You are not going to be able to tell every one how to make perfect nuts and bolts with your charts or what ever.
Rick would not ever call someone a liar! Maybe call you out for a little more argument, but not call you a liar. Now listen up! We do not want to start the petty BS that the some of the other forums seem to thrive on and I for one will not put up with it here. STOP
Mel

 

[Bogstandard]

I have to put my two pence worth in here, and then hopefully everything will be kiss and make up.
I support both sides.
I have bought nuts and bolts that were not up to standard, even to the stage of no threads on either bolts or nuts. But as far as I am concerned this is a quality control issue, not a manufacturing one.
Ricks argument is that he is a good machinist and quality control was his priority, enough said.
But there are manufacturers, especially from the far east who don't take quality control as an issue, they are just after production. So you can end up with rejects in your little bag from the harware store.
When I was in mass manufacturing, we had what was called the 2% rule.
In theory if a bag should contain 100 items, all should be good, but you were allowed to have 2 missing or bad items, but on the other hand if you put 103 all good items in a bag you could in theory be prosecuted, but no one ever complained about that.
So please gents, we are all grown men here, both of you have very valid points.
And to reiterate what Mel has already said, LEAVE IT AT THAT!!!!

 

[bob ward]

This seems to be a bit of a problem with the more modern lathes. They don't have slow enough spindle speeds.
They say that you can cut XYZ number of threads on a lathe, but you have to have the reactions of a s**thouse rat to be able to stop the cut in time because of the faster spindle speeds, or you end up with an excessive and out of scale runout groove.
This is the one time when slower is better.

When cutting fine threads into a shoulder, is there a downside to turning the tool upside down and running the lathe in reverse? Assuming the lathe can be safely used in reverse of course.

 

[Tin Falcon]

Well guys I did it . I finally tried the up-side-down and backwards threading method. Out side of having to take the lathe apart and put it back together it worked pretty well. I ground a little tool similar to ricks out of a 3/16 blank I then set it on top or a second blank to help with tool hight.
I used the 7 x 10 which is not real rigid anyway and it has a A2Z cnc QC tool holder so light cuts are in order anyway. IIRC the slowest speed on the lathe is around 100rpm so doing the pack nuts for an Elmer's engine with 3/16 worth of 10-32 thread does not take long per pass. I would not even try threading into the shoulder on this. I usually use a die for something like this but decided it was a good time to try the single point tool .
Jim

PS the disassembly of the lathe had to do with overdue PM. The threading project just brought the need to light. It was not the cause.

 

[Bogstandard]

Hi Jim,
There is a slightly easier way to do thing things like this especially the reversing bit when the lathe speed is too fast.
Basically two methods.
If you are cutting fine threads, low leadscrew speed, then a handle locked up the a*** end of the mandrel (with the motor belt disconnected). Then you can turn as slow or fast, fwd/rev as you like. There are many designs on the net and one could easily be made.
For cutting coarse threads, fast leadscrew speed, then a handle on the end of the leadscrew is used to turn the lathe, again with motor disconnected. Many lathes have them fitted as standard.
The reason for the two different methods is that when cutting coarse threads the strain on the drive train is very high (I think this is what caused the failure of the drive train bolt on my lathe a couple of weeks ago), so by driving from the leadscrew the pressure is taken away.
OK both will be slow methods, you can stop, go and have a cup of coffee half way thru a cut and come back and carry on, but you can try all your prototyping and wierd setups in true safety without the fear of mashing your lathe.
I will be using the second method when I come to do some more ornamental turning.

John