Author Topic: Clutch nuts  (Read 332 times)

Online RDfella

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Re: Clutch nuts
« Reply #15 on: 25.06. 2020 17:45 »
You didn't do physics at school, Neil? Moving something further requires more effort (harder). Simple principle of levers.
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Online JulianS

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Re: Clutch nuts
« Reply #16 on: 25.06. 2020 18:23 »
It is force x distance.

For a given force at the clutch end, the short pivot moves through a greater angle than the long pivot, so less effort required.

Online Greybeard

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Re: Clutch nuts
« Reply #17 on: 25.06. 2020 18:23 »
You didn't do physics at school, Neil? Moving something further requires more effort (harder). Simple principle of levers.
No, I didn't do Physics at school. In fact, I left school at 15 with no exams taken and got a job at £5 a week in a small engineering factory, sweeping up and a bit of capstan lathe operating.

Looking again, I can see it now. If I consider force coming from the clutch, via the cable. It would be easier for that force to overcome a hand on the lever on the top version as the leverage between cable and fulcrum is longer. So conversely, more effort is required from the hand to overcome the clutch springs. Thanks, RD.

Offline Jules

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Re: Clutch nuts
« Reply #18 on: 26.06. 2020 07:49 »
Ok then so to "correct" Neil's drawing it should say less leverage/more travel/harder to operate on the top drawing with the larger pivot distance and vice versa for the lower picture with the shorter pivot distance. The only question remaining then is experiential, does the short pivot distance give adequate travel for the standard 6 spring s/a clutch (assuming its properly setup)??…... because this would seem to be the best option to try and build with.....
It also explains (a little I think!) why a lot of the clutch levers you see on old bike pics look "Gorky" somehow, with the lever seemingly at a very wide (odd looking!) angle eg take a look at Richard's pic of the Matchless clutch lever.... or did I miss something in all this discussion? cheers

Online JulianS

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Re: Clutch nuts
« Reply #19 on: 26.06. 2020 09:24 »
A page from 1958 Hap Alzina catalogue with some lever dimensions.

Another advantage of the 7/8 cntre is a lesser handspan needed fo comfortably operate.

Online UKlittleguns

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Re: Clutch nuts
« Reply #20 on: 26.06. 2020 13:02 »
Hi Everybody,

Thank you all for your excellent replies to my original post.  Job now sorted.

The problem was caused by my advice to set the nut heads level with the end of the studs and the sharpness of the spring ends.

As such the nuts recess into the spring carriers so there no way you can put any shim between the heads and springs, and the sharp spring ends simply plough into the underside of the nuts when trying to undo them. 

Brute force eventually got them off.  Put a chamfer on the spring ends and everything started to work.

Bit sad for brand new kit. 

Regards to all