Thread cutting dies

[KMSK1]

I need some help with a thread cutting die ,,, 3mm x.50 ,,
I use a hex die holder in my tail stock on my lathe I cut a .440 long thread on a 1/8" shaft , I have been using a Irwin Hanson die's ,,They don't last very long ,and have been looking for a better die...
Anyone know of a better die ,,Thank you,,, Robert
Don't want to cut them on my lathe would have to remove DRO,,

 

[bazmak]

I dont fully understand what you are doing.Are you holding the die in the tailstock and cutting the thread under power or turning the chuck by hand//
Many years ago i had a lathe at home and sub contracted to do jobs
one of which was threading the ends of 6mm dia bar.With the lathe on slow speed i pushed the tailstock on to the job and allowed it to be pulled in,at the required length i stopped and then reversed the lathe to push off the die
Only partially successfull as the push off sometimes stripped threads.Had to do
hundreds and carbon steel dies did not last long so had to buy HSS dies
5 times the cost but lasted 5 times as long.Main problem is the continuous cut
does not chip break.I have just run a thread Bazmak Diary of a beam engine
and detailed a quickdieholder for the lathe but turning the chuck by hand
1/2 turn forward and 1/4 turn back.Works really well on S/s.I only use the more expensive HSS dies now and never have a problem.The same die have lasted many years .Regards Bazmak

 

[abby]

I do not understand "hex dieholder" hexagonal dies are die nuts , chasers used to clean damaged or part finished threads . As already said use a split die made from HSS , carbon steel is ok for brass but won't last long on steel without re-sharpening. If you have hundreds of parts to make then a coventry die-head or similar is the way to go.
This movie is actually putting a 3mm thread on 1/8" steel with a diehead.
http://youtu.be/Y-r7mEnJmNo

 

[gus]

I do not understand "hex dieholder" hexagonal dies are die nuts , chasers used to clean damaged or part finished threads . As already said use a split die made from HSS , carbon steel is ok for brass but won't last long on steel without re-sharpening. If you have hundreds of parts to make then a coventry die-head or similar is the way to go.
This movie is actually putting a 3mm thread on 1/8" steel with a diehead.
http://youtu.be/Y-r7mEnJmNo

Hi Abby,
Thanks for showing us the video of the Coventry Auto Thread Die.Was very fortunate to be given the task of setting up same for demo in Trade School in 1963.Thats 51 years ago.The Trade School was very fortunate,Gus did not demolish the Auto Die.
My classmates had a chance to auto die thread. In those days,it was hi tech. Our instructors had not heard of thread rolling.

 

[gus]

Here's my DIY tail stock die in action. I made die holders from M3--------M10. All manual but using a ratchet wrench to make it user friendly. All dies are Japanese Carbon Steel Dies. Been using these since 2011 and thats a lot of thread dieing.Tapmatic Tapping Fliud makes thread dieing easier on the hands.arms and extend die life. Normal lube oil will not help form good threads.

 

[ShopShoe]

KMSK1,

I would agree that moving away from Hex Dies is the way to go. Higher quality round dies are also adjustable: There is a screw to adjust the amount of "squeeze" the die puts on the part being threaded. Round die holders are easy to get or make. There are also many more sources for round dies.

My own experience with Irwin Hansen taps and dies is variable: Some have been very good and long lasting, others have been done after one use in easily-machined steel.

--ShopShoe

 

[KMSK1]

Thank you guys for all the info,, It has been very helpful ,,,My die holder has a hex type clamp head ,,, I will look for HSS die and better cutting fluid .
I have been holding the 1/8th dia shaft in the chuck and the die in the tail stock and cutting threads on slow,,, under power ,,,

 

[ruzzie]

Question- Are you trying the cut a M3 thread on a 1/8" (3.175mm) Diameter shaft?
The shaft diameter should be a maximum of 3mm if not 0.1-0.2 mm smaller.

 

[bazmak]

Hi gus,i like the idea of the rachet spanner.These can be bought cheaply
and would be ok for light use.Will try again later to improve to your standards
Also plan to redo the drawers for the mill.Planning to go full width across the bench and this will also give me a raised area of bench.When assembling the beam engine it was too low and gave me bad back stooping.Looks like i will have to spend some pennies on some tree wood

 

[Krutch]

KMSK1,
As you have already read the hex dies is not for cutting threads but for chasing them to clean or finish. They will tear the thread upon back off. If you can start the thread with single point then use the hex die you will have more success. At that size it will be difficult to start the thread without tailstock support. One could use a bushing to feed the work through with the cutter immediately behind the bushing. This give the threaded part of the shank some support to stop push away. Then the die can be used to finish. "To a shoulder" is the area of problem.
If you can pick up the thread with the tool, then the thread can be cut to a shoulder. Tough at that size, but can be done.
Still a good HHS cutting die is preferred instead of the rethreading hex tool.

If ya want a real challenge, make a suitable bushing and a way to hold it like a follow rest and cut about a third of the bushing so you wind up with a C shape looking length wise. Adjust the bushing so the threading tool can access the work and moves with the tool to cut the work. Small cuts and then your rethreading die should get the job done. Plus you have a set up for that particular size & thread and know how to do so with any other small thread. Plan ahead with the bushing mount to allow for several bushing/thread sizes. Some will think you a genius! Others, lazy. But you'll get your job done.

 

[gus]

Question- Are you trying the cut a M3 thread on a 1/8" (3.175mm) Diameter shaft?
The shaft diameter should be a maximum of 3mm if not 0.1-0.2 mm smaller.

Hi Ruzzie,
I am with you. Having the job O.D. slight smaller sure helped. To make it easier for the die to engage and commence threading,a deep chamfered end sure help prevent tearing. A good drop of Tapmatic Fluid makes die thread smooth,easy and good. Just measured a M3 socket head screw and it measured 2.85mm O.D.

 

[SilverSanJuan]

Is there a process for using a split die? Should the die be spread for the first pass, and then squeezed for subsequent passes?

Todd

 

[goldstar31]

The average Hexagon die is probably fine if all that you want to do is clean up threads that have become butchered- or maybe your wife wants the garden gate mended. Again, The correct way for a model engineer to thread is first to screwcut and then to round the crests( If you are a Whitworth freak like me), use a die.

Of course it assumes that your lathe is a screwcutting one- and that you can actually screwcut( clears throat)
If you want to use a die holder, then you shouldn't really use one of those things- with a couple of handles but a die holder that is held true in the tailstock and slides in line with the thread which is needed.
One of the first things that a newcomer to engineering makes is a reversible die holder to hold the different sizes of round dies. Mine is so old that I have forgotten when but it has a jumper from No1 Morse taper up to No2. Actually, I found a Number 0 MT when rooting in my drawers.

I was having a bit of a tidy up today and found a collection of Number 2 MT shanks with a different size of Centre drill in each. I found another with a half centre and one with a square pyramid shaped end - to pull wrongly placed centres square. Anybody remember things like them?

Regards

Norman

 

[Swifty]

Is there a process for using a split die? Should the die be spread for the first pass, and then squeezed for subsequent passes?

Todd

I usually set up the split die using an existing screw of the correct size. I have my smaller dies permanently set up in holders that I use in the tailstock chuck, the threads are done in one pass only. Most times, M6 and above, I screwcut with a single point tool.

Paul.

 

[Toolguy]

You can make a thread gauge of any desired size by drilling and tapping a hole. You may want to make it in tool steel and harden it.
For threads over a 1/4" I usually single point first to a little oversize, then chase it with a die for final size and finish. I will start out with the die a little expanded, then close it a little at a time until I get the fit I want in the gauge. Then I leave it at that setting forever or until there is a reason to change it. This way you can make standard sized threads quick and easy for months or years to come.
For sizes under 1/4" I will usually do the same thing without the single point operation. I just did this on a medical related part made of 17-4 SS 2 days ago. It was a M3 x .5 thread. Now my M3 die is set.

 

[bazmak]

Just my tuppence,when the die is mounted in a good quality die holder,i i finger tight the screw into the split and then loose nip the squeeze screws.Thread is then almost always right.If the thread is too tight then i loosen the split screw and tighten the squeeze screw slightly.I always take out the dies after use and redo every time,only takes a minute Bazmak

 

[MachineTom]

A split die is intended for getting the type fit you want on your threads. Not a rough/finish procedure. Grab a cheap hardware store 3/8 bolt, and a nut, when screwed together the nut will rattle on the bolt. Now grab a 3/8 grade 8 bolt and a class C nut, when screwed together no rattle. Thats the difference in fit.

The way to set them is after cutting a test thread, measure the threads over wires, and adjust to a 2B fit. After all its not quick production your after its something that is yours.

Do your want to think the not yet born grandkids say, grandpa was sure a lousy model maker, look at his threads!!! LOL

 

[goldstar31]

Hoorah, is this the first time that someone is prepared to talk about tolerances in manufacture?

Thank you

Norman