Cota 172 Restoration

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David Lahey
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Re: Cota 172 Restoration

Postby David Lahey » Thu Sep 27, 2018 6:54 pm

Have you tried a high pressure washer like a Gerni. Put truck wash on the fins until it dries then water blast.


relax, nothing is under control

Phil 850
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Re: Cota 172 Restoration

Postby Phil 850 » Wed Nov 14, 2018 8:27 pm

A bit more progress.
I removed a spoke from each wheel to see what they clean up like and they don't look too bad.
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IMG_4281.JPG (119.08 KiB) Viewed 934 times

The top one is the rear and measured up to M4 x 0.75 pitch and both the spoke and nipple threads cleaned up nicely.
However the front measured 3.2mm x 0.75 pitch which is not a standard thread of any metric description.
In imperial it might be 1/8" x 32tpi but I can't find that as a standard of any description either, and neither can my local bolt specialist.

Any ideas ?
Phil



18ss
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Re: Cota 172 Restoration

Postby 18ss » Thu Nov 15, 2018 2:07 pm

3.2 mm equates to 10g spokes which were fairly standard on the front wheels of british bikes. Anything pre-69 will use them.



Phil 850
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Re: Cota 172 Restoration

Postby Phil 850 » Thu Nov 15, 2018 9:10 pm

So is there a particular designation for a 10g thread so I know what to ask for to buy a tap and die ?



18ss
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Re: Cota 172 Restoration

Postby 18ss » Sat Nov 17, 2018 7:40 pm

Not that I can find. A 10g spoke should be 40 tpi. If the thread gauge says 32 tpi a unc 32tpi no.6 may do. As you stated there is no metric equivalent that would work. I would probably try, if the threads were too rough a 32tpi thread file or if they are just crudded a touch of fine valve grinding paste and screw the nipple up and down a few times.



Phil 850
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Re: Cota 172 Restoration

Postby Phil 850 » Sat Nov 17, 2018 9:48 pm

Thanks for the info.
It's mainly the thread in the nipples where spokes finished the thread is a bit rusty and I'd like to clean them out before I reassemble them.



David Lahey
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Re: Cota 172 Restoration

Postby David Lahey » Sun Nov 18, 2018 10:23 pm

If you can find a spare spoke with the right thread, make your own tap from it by cutting flutes into it.

If the crud in the nipple is rust you can dissolve the rust with phosphoric acid then if you want it to look fancy, re-plate the nipple (aid will remove zinc plating).
I've done the acid treatment on two complete sets of steel spokes and nipples because they were otherwise perfectly good.


relax, nothing is under control

Phil 850
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Re: Cota 172 Restoration

Postby Phil 850 » Mon Nov 19, 2018 9:03 pm

What did you do about replating the spokes and nipples ?



Phil 850
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Re: Cota 172 Restoration

Postby Phil 850 » Mon Nov 19, 2018 9:05 pm

Fully stripped the rear wheel.
Now do I polish the hub or leave it the original satin :|
IMG_4295.JPG
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David Lahey
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Joined: Thu Jun 05, 2003 7:01 pm
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Location: Gladstone, Queensland

Re: Cota 172 Restoration

Postby David Lahey » Mon Nov 19, 2018 10:10 pm

Phil 850 wrote:What did you do about replating the spokes and nipples ?

I couldn't be bothered setting up the plating kit to zinc-plate them, but I did paint them before reassembling the wheel. About 10 years after that, replacement (plated) spokes became available for a reasonable cost and then when I next machined the brake drums, I fitted the new spokes.


relax, nothing is under control


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