aljohn

Oh dear ! $200++++ !!! I really hate to mention that the complete bike only cost me £40 5 years ago. I spent another£60 and thought I'd really bagged a bargain. I didn't realise spokes weren't threaded with a die cutting the steel but had to be done with machines costing trillions of dollars...alright, I exaggerate, but wow!
I thought I'd only asked a simple question but I obviously had no idea what I was asking. Thanks to everyone for their input, I do appreciate it.
I have built bikes, replaced spokes and trued wheels and generally considered myself fairly competent with bikes. I use this forum for information when I come across anything new and feel confident carrying out the instructions given. But it comes as a bit of a shock when I find I know very little actually about spokes... But that's why I love forums, answers are freely given by helpful folks to anyone who asks.
Sorry to go on a bit but you have brow beaten me to (happily) buy new spokes. Happy New Year

Dan Burkhart 

I don't see a way to do that as the limit stop is also the inner guide for the movable die. If such a need ever comes up, I can still dig out the good old Hozan and extend the threads.
As to your other question, my medium range plan is to fully retire off the road (sorta semi retired now) and ramp up my services with a particular focus on wheel building, so as is my wont, I went with the best tool I could afford.

cranky old road 

Ah, when I think of my carefree youth when I would build a wheel with the spokes at hand and then grind of the mm or 2 that protruded from the nipples.... I think I still have a pair of those around but probably haven't ridden them since I put on 50 or 60 lbs and developed my now massive guads.

Doug5150

Yea, but I've not seen it shown that spoke threads must be rolled; only that due to the small diameters used, rolling is most-convenient. Most threaded fasteners on most machinery all over the world,,,, does not require rolled threads.

I agree here. On an industrial scale, rolling threads is usually faster & cheaper than cutting them. If you are threading long pieces (6-foot rods) or small diameters then rolling is best just because it is automatically-self-centering, even if the original piece of metal isn't straight to begin with. Thread-rolling setups are industrial-level tools with industrial-level prices however: a die to cut 3/8-16TPI threads costs ~$10, and a rolling head to produce the same threads costs ~$3500+, and that's assuming you attach it to a lathe and not a proper thread-rolling machine.

Yea but a person without metalworking equipment couldn't get a die started straight on a plain rod if their life depended on it. Sometime take a 1/4" piece of steel and a threading die in a hand wrench, and see how far you can hand-turn it before it jams. You will be lucky to get beyond 2 inches.



I have meant to order a 2-56 die and try to thread a spoke just to see how well it goes. I've forgotten every time I've sent another tool order tho'... :|
Even if it works, the dies are only $7 or so but they're not gonna last long cutting stainless steel spokes. Carbon-steel ones might do better, but they won't last forever either. So once again there is a cost issue to consider.

FBinNY 

To correct the misinformation here.

While rolled vs cut threads is rarely if ever required, once you've decided on one or the other you're 100% committed. That's because the blank size is different.

In a rolled thread, the blank diameter is exactly 1/2 way between the root and crest diameters. The process flows metal from root to crest, so the final thread is larger than the blank. Cut threads call for a blank diameter matched to the crest diameter, and the entire thread is cut into the blank with the excess material removed as chips.

Having cut threads for a living, I've never had an issue cutting long threads by hand when the situation called for it, nor have I had a problem starting dies square by hand (some skill and patience required).

Now as for extending the rolled spoke thread with a die, there's two issues. If you intend for the thread to support load, you're out of luck because the resulting half thread form will strip the nipples. But if you only need to extend the thread 1-5mm you're OK because the end threads which engage the nipple head are still full profile, and that's where it counts. All you've done is created clearance for the nipple to go a bit farther.

When I've needed to, I've approached this the other way, by using a 2mm drill to increase the bore depth at the front of the nipple (hub side) so it'll thread deeper.

Now, why rolled threads are inherently superior for spokes.

The thread height of a 56tpi thread is .012. On a rolled thread that's half outside the blank and half inside, so the thread of a .080 (14g, 2mm) spoke cuts into it .006" or 7.5%. If a similar 56tpi thread were cut into .080 wire, the minor diameter would be reduced to 0.068, or by 15%. Calculating the resultant loss of strength we have roughly 33% loss with rolled vs. 43% with cut. This is very significant and if spokes were produced with cut threads thread failure would be a common rather than rare problem. Of course we could compensate with larger blank material, but what would be the point.