I have a thread here I can't find a standard size for, it is off of my bicycle (an older non-high performance Norco mountain bike, it was made in Taiwan). The nut holding the crankshaft on is stripped, the threaded rod is 0.385 inches (measured with a digital caliper) and looks to be about 20 TPI (sorry don't have a thread gauge at home). A 3/8 fine nut will not fit on (which is what my boss thought it would be looking at the stripped nut, though the stripped nut did fit on a 3/8 fine bolt). Anyone have an idea on the thread size I need so I can buy or make a new nut? Ken
Mystery Thread
Jun 07, 2005
14 Replies
hmmmm.... M10 X 1.25
pep boys should have these for about .99 or so.
sjm1
And no it doesn't seem to be metric either (9.78mm) Ken
Never mind I was looking on the wrong page of the Machinery's Handbook. Ken
That sounds right. Bicycles have been all-metric for _years_.
------------------------------------------- Tim Wescott Wescott Design Services
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Might get a better thread measurement by measuring the distance of 10 threads and dividing by ten for metric thread pitch. ....much easier than measuring two adjacent threads.
But 10*1,25 is not as common as 10*1 (haven't checked my bike). Better recheck!
Nick
Not yet they aren't.
Bicycles are a fine example of "standards, it's a good thing there are so many of them".
Campagnolo axles - 10mm x 26 tpi.
Maybe but there is not enough length for me to measure 10 threads, I did however measure a 1/4 inch and count the threads (just over 5). Ken
Bicycles are about as non-standard a product as you could immagine - with bolts sized metric, with threads per inch spec - and half mm sizing - like 9.5mmX26 axles etc. The crank nut is not a standard nut either - either a serrated flanged nut or a "race nut" 0 with a captive free-rotating washer are common. Just get a replacement nut - they are cheap(relatively) and readily available from your local bike shop - who WILL know which one fits a Norco.
10mm-1 is fairly common with bicycle parts.
N333(TOOL CALL N334G0G17G40G80G90M5M9 N335T5M6((TAP 10MM -1 N336X0Y0E1S900M3 N337Z3.D5H5M8 N338(TAPPING N339G0G80Z1. N340G84R+0.25Z-0.67F35.46S900 N341G80R+0.25
Verify the pitch yourself, Im too lazy..thinking it was appx .0394in/turn.
I'd ask the question on rec.bicycles.tech(or something like that), they're a pretty savvy group that will probably take you in the right direction. Pat
I agree.
Still, it wasn't me that was asking the question--so I suggest maybe you should work on it a bit--a direct reply to any of my posts is usually like a big red flag for me....
Cheers,
Hey another Campy fan! Bravo!
:-)
I also credit Ken for asking about the v-thread on the bike.
...-many- would merely turn a big wrench on the 3/8 nut knowning full well the nut would just -cut- new threads and call it fixed :-)
the 10 X 1.25 was based on my acute internet vision..... :-)
....and for those who like to keep track of such things:
a M10 x 26TPI = 1/26 = 0.038461538461538461538461538461538 then
1.0mm = 0.03937007874015748031496062992126 so0.03937007874015748031496062992126 -
0.038461538461538461538461538461538 = 9.0854027861901877649909145972138e-4thus 26TPI is dang close to 1mm.
:-)
sjm1
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