Threads for Commando?

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Going over the shop manual, I find only one mention of thread standards. And it doesnt even give the standard. (its the centre bolt for the auto advance, look under Contact breaker in Tech data. Its says 1/4" X 26 tpi... A search in the forum doesnt give anything. Im sure its there. Where do I look?
 
1/4 inch x 26tpi is either Cycle thread (BSC) or BSF. Only difference is the thread angle. BSC is 60 degrees and BSF 55. There is a huge mixture of threads on a Commando.
 
I normally only make verified updates, but when L.A.B says it, I trust it.

Norvil Motorcycles list it as BSF...
"060720, BOLT - CENTRE - FOR POINTS CAM - 1/4" BSF 1967 ONWARDS"

...and rotor bolts supplied with Boyer, Pazon, Tri-Spark, Wassel/Vape, etc. electronic ignitions for the standard Norton camshaft are "1/4 BSF" (plus a 1/4 UNF for non-standard camshafts or other models, Triumph etc.).

Edit: +
https://www.classicbikespares.com.a...-contacts-timing-cover-oil-pump-relief-valve/
12Contact Breaker Cam Bolt0607201Centre, 1/4" BSF x 2-1/4".
 
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According to the spreadsheet I have there are 3 types of 1/4" x 26tpi threads
Brass and BSF (almost identical with 55 degree threadform) and CEI (with 60 degree threadform)
If anyone would like a copy of this spreadsheet (nearly 600 types), PM me with your email address
Cheers
Screen Shot 2020-09-23 at 8.20.09 am.png
 
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You might be wrong about the 1/4 inch brass thread. I make my own needle jets out of brass hex. I think what is called 1/4 BRASS is much bigger than 1/4 inch. The number for the die nut I use is B 0. I think that is a brass designation, and it is coarser thread than BSF.
 
Be aware that the cam bolt thread depends on who made the cam. 1/4-26 for OEM and 1/4-28 for Megacycle cams.
 
stainlessbits hasn't been updated in many years. This is actively updated and more easily searched: https://www.gregmarsh.com/MC/FastenersList.aspx and you can update things as you find errors. For instance, L.A.B just corrected this thread saying the bolt is BSF so I updated mine to BSF. I normally only make verified updates, but when L.A.B says it, I trust it.
Looking in the shop manual for my A65 1968, I find a list of thread standards used on the bike. I dont seem to find the same info for my 71 Commando? Sure would make life easier if it was possible to find...
 
Looking in the shop manual for my A65 1968, I find a list of thread standards used on the bike. I dont seem to find the same info for my 71 Commando? Sure would make life easier if it was possible to find...
Here are the standards related to Nortons currently in my database:

BA
BSC (CEI)
BSF
BSF/BSC (CEI)
BSP
BSW
UNC
UNC/UNF
UNF

Is that what you want?

If you want to know the standard and size for a specific fastener, you can easily look it up. If it doesn't exit, you can figure it out and enter it, so ask if I can.
 
Can't be both as BSF and BSC/CEI are not the same thread form.

Ok (also 40 ME for the carb top adjusters (although they're not exactly fasteners).

Also, a few special threads (UNEF, UNS, UN20) not necessarily fasteners.
As far as I know, BSC and CEI are the same thread form and BSF is different. If there's something wrong with that - I'm all ears.,

BSF/BSC (CEI) is part NM24389 (06.7885) Head stud, size listed as 3/8" x20 BSF - 26 CEI x 1-7/8", was in the original database and was verified by a user. If wrong, please provide what is correct.

UNC/UNF is lists as part 702880 which is unknown, type is stud, side is 3/8"x16-5/16"x24, was in the original database, unverified and I have no idea where it goes, if anywhere. Could be a Matchless or Villers part as stainless bits had them grouped with Norton which is something I'm slowly fixing.

The original database had no UNEF. If any exist on a Norton, please tell me and I will correct them. Same for UNS and UN20. Didn't realize about 40 ME - I though Amal use BA but never checked.
 
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