hello and a interesting problem

[roy thersbyParticipant @roythersby44989]

altering 4mm spoke stock.

[roy thersbyParticipant @roythersby44989]

hello thanks for the add into this world of engineering. I am a wheel builder and frame builder for motorcycles, and as machinery for this type of engineering is so limited I have to make a lot of the machinery and convert what is out there to suit my requirements

I have a problem and wonder if any members may have made a small machine or know of one to do the job.

I have a Waterbury Farrell thread rolling machine using flat dies, I have recently tried to roll m4 x 7 threads onto 9 swg spoke stock, it produces a good thread alas it is reading 3.95 od, standard m4.7 threads read 3.80 od, although the thread is snug in the nipple, I am using 7070 aluminium for the nipples and using cut thread die both in a drill tap and or a drill and tap, these nipples are machined in a cnc machine as the opposing thread on the nipple is m4 ,7 LH thread. the rod stock is not available in the metric size, and I was looking for an idea to cut the spoke to size then reduce the proposed threaded end to the prescribed size required ready for rolling, the reduction process can be either ground or rolled, an engineer said today that if I turn the die blocks around it may reduce the rolling area to what I need, this I can see a problem as there would be no grip to roll the spoke stock between the die heads, increasing pressure of the die rolling heads to try a deeper cut and reduce the size that way will lead to the spoke stock squashing in the die, if it does that it jams up the machine and 15 mins is spent stripping and resetting the machine back to working order, the spoke length to be used is 100mm and 35 mm, and the reduction has to be done in seconds…. any ideas or has anyone seen a machine out there that may do the job, also I am looking for a heading tool to put spoke heads onto spoke stock, its a bit like forming a small nail head onto the end.

[Martin ConnellyParticipant @martinconnelly55370]

Could you have 2 carbide dies with a semi circle of the desired size formed (with a cutting edge) in the edge of each die? With the dies slightly apart put the end of the spoke into the gap against a suitable stop, close the dies and pull the spoke out to scrape away the small amount of material needed to size the end. The hardest part may be forming the hole with a cutting edge in a die.

Martin C

[Neil WyattModerator @neilwyatt]

Hi Roy,

I understand that this is a safety critical application.

According to this source your rolled threads are within tolerance for ISO 965 at 3.95 while the 3.80 threads are undersize.

I would go by the spec, rather than measuring a bought in thread of unknown quality.

This source says they are in spec too.

Neil

 

Edited By Neil Wyatt on 23/11/2017 21:28:59

[HOWARDTParticipant @howardt]

If you are rolling threads on the spokes why not fluteless tap the aluminium nipples.

[clogsParticipant @clogs]

Roy,

why ally for the nipple's other than weight.. ? how much does it save…?

I always have nickel plated brass……..just interested…….

thanks……. clogs

[JasonBModerator @jasonb]

 

Why not just buy metric spokes? they come 3.5mm dia rather than 9g which is 3.6mm dia so should solve the problem.

 

Edited By JasonB on 24/11/2017 07:52:33

[jimmy bParticipant @jimmyb]

The size is good, M4 x .7 thread, major ( for 6g ), should be 3.978 to 3.838mm.

jim

[jimmy bParticipant @jimmyb]

Neil's last link, no working here.

I generally use this as my "go to" for standard metric threads **LINK**

Jim

[roy thersbyParticipant @roythersby44989]

Posted by clogs on 24/11/2017 07:27:14:

Roy,

why ally for the nipple's other than weight.. ? how much does it save…?

I always have nickel plated brass……..just interested…….

thanks……. clogs

Hi Clogs The alloy nipple weigh 2 grams the steel nipple weighs 6 grams x 32 spokes ally 64gram and 192 gram, the bikes these are fitted to are trial bikes and they like to have the bikes as light as possible, and they throw them around in all sorts of hard to do stunts. in road racing it was always said go to the loo before you race the weight difference could be worth £1000's to achieve the same weight loss… so I am told, I always picked a small light rider for mybikes.

[roy thersbyParticipant @roythersby44989]

Posted by HOWARDT on 23/11/2017 21:36:55:

If you are rolling threads on the spokes why not fluteless tap the aluminium nipples.

I have thread forming taps on the way and this will be tried out this coming week, thanks for the intrest

[roy thersbyParticipant @roythersby44989]

Posted by JasonB on 24/11/2017 07:50:26:

Why not just buy metric spokes? they come 3.5mm dia rather than 9g which is 3.6mm dia so should solve the problem.

Edited By JasonB on 24/11/2017 07:52:33

[roy thersbyParticipant @roythersby44989]

I am one of the only guys in UK that makes spokes in metric threads and especially in RH and LH thread formats the only other supplier does them in a steel format then plates then causing to attract enbritlement of the steel, and the last thing you want is coming of a jump and the spokes snapping their head off. the stad supply of british SWG spokes is still boyant but in the new cases of bikes the manufactures are changing over to certain gauges to make sure customers buy their spoke stock, a Italian wheel just coming onto the market has a spoke at £4.50 and the nipple which is a tubless style @£6.50 making a cost on 1 spoke and nipple £10.00, x 36 £360.00 plus a building charge makes the back pocket thinner very quickly

[Author]

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