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Discussion Starter · #1 ·
Arrrgh!!!!!!!!!
The spokes I ordered are about 3mm too long!

They are DT Swiss double butted 2.0/1.8/2.0.(14/15/14). I want to shorten them and add extra threads. I want to do this by using a die to cut them. I know that rolling them is better, but I do not have the machine to roll threads.

According to the Park Tool website, the typical 2mm spoke has a 2.2mmx56TPI thread. This converts to a 2.2mmx0.45mm metric thread pitch. Should I order a 2.2x0.45 die to cut the threads, or a 2.0x0.45 die?

Can I use a standard 2-56 die? I do not know if the diameter of a number 2 standard bolt is equal to 2mm(14 gauge).

Has anyone here ever done this?
 

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Can't be done the way you want

The spoke threading is rolled for a reason. When the thread is rolled on some of the spoke material is actually pressed outwards and the threads end up with a larger diameter than the spoke wire. This is not possible to replicate by cutting the spoke wire and you will end up with threading that is smaller in diameter than the corresponding thread in spoke nipples. Also, if you managed to find a smaller nipple that caught the new cut threads you will likely find the spokes prone to breakage because of the smaller diameter inside of the cut threads.
 

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lord humongous is correct. you'll need to get a thread rolling die for 56tpi. hozan sells one for 14/15 ga. spokes, but this thread rolling machine will cost at least $100 if not more. it would be cheaper to buy new spokes or have a bike shop do it for you.
 

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Discussion Starter · #4 ·
Lord Humongous said:
The spoke threading is rolled for a reason. When the thread is rolled on some of the spoke material is actually pressed outwards and the threads end up with a larger diameter than the spoke wire. This is not possible to replicate by cutting the spoke wire and you will end up with threading that is smaller in diameter than the corresponding thread in spoke nipples. Also, if you managed to find a smaller nipple that caught the new cut threads you will likely find the spokes prone to breakage because of the smaller diameter inside of the cut threads.
I am aware that rolled threads are superior to cut threads, for the reason that you mentioned. I am willing to risk a slightly narrower spoke diameter rather than wait for spokes to arrive from my supplier. I am not a very heavy rider, so a slightly weaker spoke should not be an issue. If the cut threads end up smaller than the threads in a standard nipple I will try some smaller DT Revolution nipples to get a closer tolerance fit.

To answer my own question, I have learned that a 2-56 thread is functionally identical to a 2.2x0.45 metric thread. That will simplify the die procurement process.

I would cut the spokes and reroll the threads, but I need to save some of the threads that are already on. Using a die will allow me to keep some of the threads that are there and cut new ones without shortening the spoke too much. After the new threads are cut I can trim the excess length, or just leave it if it is not a problem.
 

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disease said:
I am aware that rolled threads are superior to cut threads, for the reason that you mentioned. I am willing to risk a slightly narrower spoke diameter rather than wait for spokes to arrive from my supplier. I am not a very heavy rider, so a slightly weaker spoke should not be an issue. If the cut threads end up smaller than the threads in a standard nipple I will try some smaller DT Revolution nipples to get a closer tolerance fit.

To answer my own question, I have learned that a 2-56 thread is functionally identical to a 2.2x0.45 metric thread. That will simplify the die procurement process.

I would cut the spokes and reroll the threads, but I need to save some of the threads that are already on. Using a die will allow me to keep some of the threads that are there and cut new ones without shortening the spoke too much. After the new threads are cut I can trim the excess length, or just leave it if it is not a problem.
There is no such thing as a Revolution nipple. All 14g (2.0mm) nipples are the same spec and you will not get a 15g (1.8mm) nipple to thread on.
 

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Discussion Starter · #6 ·
My wheelbuilder has informed me that he can add rolled threads onto my long spokes with a Wheelsmith spoke threader/cutter. That will leave the existing threads intact. He can then simply trim the excess length if necessary. Problem solved.
 

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Discussion Starter · #7 ·
shiggy said:
...All 14g (2.0mm) nipples are the same spec and you will not get a 15g (1.8mm) nipple to thread on.
You are probably right.
 

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OK to qualify this...

In some curcumstances, cut threads are fine, in others they are BAD.

Cutting a thread, is really driving a micro-plough, through the metal, and tearing a "thread shaped" groove out of the nice aligned grain metal, leaving lots of nasty little stress raisers in it's wake.

The groove is full of torn and ragged rips in the metal surface and the grain of the metal is interrupted by the cuts.

In the application of highly stressed and cyclically loaded applications, this is a particuarly bad thing in a straight shaft, spoke.

A ROLLED thread, provided all the metalurgical considerations are met, like the ability of the metal to be flown into the thread form, without exceeding it's work hardening limits, etc., will squeeze the metal into the form of the thread, providing a smooth thread surface, with the grain direction of the metal flowing from the main body, into the body of the thread.

The rolled thread form also has a gentle development of the shaft, into the threaded section, where as a cut thread has tears in the metal, at the junction area - which is a disaster waiting to happen.

If it's properly done, a rolled thread, is a very good thread form, and in SOME designs and applications, a cut thread into a shaft, is an extremely BAD thing to do.

Go read some books on the failure mode of rolled and cut threads on shafts.

Frightening.
 
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