saturnhr

Has anybody ever come across a 1.37 x 24 tpi thread cutting die. I understand that there are inside taps for bottom brackets, but I am talking about outside thread cutting. I also understand that a lathe can be used; however a die would make the job so much easier.
Purpose is to cut thread for track cogs on rear hubs and to covert old Campi track hubs to new BSA 1.37 x 24 tpi standards.
Thanks for any feedback

ultraman6970

I believe there are my friend (we did something somilar back in the day in my country, from where the guy got the die who knows). The question is to find them. The best way to do what u want it is to do a sleeve, with thread inside and out and do new threads in the hub to accommodate that sleeve, use loctite or an epoxy and the thing wont get off ever.... i bet you got the idea. I believe it is not that hard to do, the problem it is to find the die and tap you might need.

Thanks.

tatfiend 

Most dies are tapered internally for ease in starting the cut on a shaft. Therefore they would not cut the inner threads deep enough for what you want to do if I understand correctly.

In manufacturing it is most common to cut threads on a CNC automatic lathe called a screw machine for larger diameter threads. Most bolts are commonly made by rolling the threads into the bolt blank using high pressure between a set of hardened rollers with the inverse of the thread form machined on them.

mikewille

hey there, this is my first post here.
i have a 1-3/8"x24 threading die i use to make adapters for holding cassette freehub(freewheel?) bodies on
rear axles on homebuilt trikes. i ordered mine from j&l industrial supply, msc industrial or mcmaster-carr
should have them too. built a die-holder from a piece of pipe rather than spend the dough on a real one.
for a short or shallow threaded area(like the edge of a rear hub) you can start the threads with the wide tapered side of the die, bottom it out, then flip it over to continue cutting full-depth threads. you might want to make sure theres enough material on the existing hub
to support the new thread size first. good luck!

HillRider

What is the current threading on the hub? If it's "Italian", then its compatible with "English" threads. The diameter and pitch are identical and the only difference is the thread's apex angle. English is 60° and Italian is 55°. You can easily thread an English cog, freewheel, etc, on an Italian threaded hub. However, once you've made the change, it's not recommended to go back and forth between thread types.

LWaB

I've got a Var die for cutting/cleaning the threads of (English threaded) freewheel hubs.

Dan Burkhart 

Flipping the die over means you are trying to cut threads with the trailing edge of the cutters.It's a really fast way to kill your die.

jccaclimber

EDIT:
I thought Park Tool sold them but I can't seem to find them after all, just the 1"x24tpi ones for steer tubes. I know of a machine shop that might be able to make them but it would be really really expensive.

mikewille

"Flipping the die over means you are trying to cut threads with the trailing edge of the cutters.It's a really fast way to kill your die. "

good point, i hadnt thought of that. perhaps they make "bottoming dies," the rough equivilent of a
bottoming tap for tapping into the bottom of a blind hole?

HillRider

True except you are threading aluminum and the threads are already at partial depth. This is pretty easy on the die.

operator

This thread is 15 months old dudes...

ItchyZipper

I recently made a die out of a steel bb shell. I cut some grooves, perpendicular to the internal threads, with a hack saw. Threaded the messed up aluminum cup into the thing...worked great! remember to use cutting fluid. I know that it is kinda third world, but it saved the day! Just don't confuse the left and right hand threads. This works fine for chasing damaged threads, don't expect to cut new ones with this rig.

feddiej2

hey mikewille,
I just found a die at Victor Machinery online for $53 that cuts a 1.375 x 24 tpi thread (60 deg) but the bloke I talked could not tell me what standard or height of the thread or anything. I guess if it is a 60 deg thread it would be forced to cut the standard cycle thread BSC. The only thing that could possibly be different would be the radii which is supposed to be .007", right? The thread height for the BSC thread is .0222. The picture shows very sharp tool peaks. One could always grind or file slightly if they were too sharp. I can measure it but not try to thread it into anything or chase something if I need to return it.
Do you think I could go wrong buying it? Another one costs double from MSC supply.
Feddiej2

no1mad 

The person you're asking hasn't logged on to this site since 9/11/2012...

feddiej2

Thanks. I think I will order the die since if you lay it out on paper it has to cut the BSC 1.37 x 24 thread and the thread height is forced to be the same.

andr0id

So are you saying we should just let it die?

fietsbob

OP Long gone But for the other readers , upright trikes I put together all have a steel keyway Shaft driving 1 wheel,

the final drive threaded freewheel mount has a opposing pair of setscrew, 1 bites into the piece of keystock.

Thanks to the China based low cost manufacturing, the freewheel Mount thing does not cost Much

If you have a Lathe and can chuck the piece in It .. the tool bit to buy fir the tool holder piece is cheaper.
To cut an outside thread the spinning piece (with the right feed rate)..
but having a lathe you wouldn't have come here to ask and probably be done by now..

ThermionicScott 

And you, in turn, replied to a 5-year-old post.

andr0id

I couldn't resist. But I think I'm tapped out now.

feddiej2

I have ordered the die. I am making an adaptor to be able to use a freewheel on the left side of the bike instead of the right. The part I am making will shoulder oppositely than the one on the right side, thus the need for the die.
Thanks for all the productive remarks about responding to an old post. Being a newbie, I am now educated on what to do. My sincerest thanks.

tthaler

Sure, I have one unused at home from Unior: Unior d.d. | Hand tools

Drivingyoumad

I'll take it

JohnDThompson 

You're responding to a years-old comment from a poster who has only posted four times since joining BF in 2010. I suspect you won't get a response.

In any case, such dies are available. In addition to the Unior mentioned above, VAR offered one as well. But they won't be cheap.

If you're just doing some thread chasing, a thread file might be sufficient.

Drivingyoumad

Oh, my stars... the embarrassment!
I could just DIE. LOL.
Just can't help but love a THREAD about THREAD!! The part about 'letting the thread, die?
THREAD, DIE!? 😂 priceless!
NOW that my very first-first, and NOW my second (ever as I've never been in a forum before 😁😁&#128513
What is "VAR"?

Dan Burkhart 

Var is a French bicycle tool manufacturer. Mostly high quality, pricey tools.