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Brit Bolts, nuts and fastners What ARE THEY? from US

Posted: Tue Nov 11, 2014 7:06 pm
by mrtnfischer
I have a MGTD, most bolts are Witworth, My 1964 TR4 is some other size???

and my Basket case 1962 Matchless(that I just found) G80 seems to be another size.

I need some bolts but what is the size reference and where can I get these nuts and bolts.
Since I don't know what to call them, how can I look for them?
Someone here in Pennsylvania said the are a "British standard"
They certainly seem close to American ASA .
Can some one shed some light on where to get these things (nuts and bolts)
For example, I need to reassemble the Norton Forks into the triple tree and I need some Pinch Bolts. (that what we call them) and ihe Matchless book they are called pinch bolts. But all my searching in hardware stores is coming up with nothing. Is there a source for these miscellaneous bolts and nuts????Or are they special for Matchless and Brit Bike.
I remember my first Tiger Cub and my T100 Triumph, it was always a problem with the fasteners and wrenches as well.
Is there a list of sizes and measuring tools needed to be proficient in all of this?

Thanks

Re: Brit Bolts, nuts and fastners What ARE THEY? from US

Posted: Tue Nov 11, 2014 8:32 pm
by aobp11
Hi Martin,

Some hints, but please wait for replies of more knowledgeable members and more details. There is general information also at Wikipedia.
Our bikes mainly used BSC (British Standard Cycle) thread at 26 TPI (for instance the engine plates bolts/studs of your 1962 G80) . You need spanners for that with indication "BS" or "W" (often both spanner size codes are present). But also BA is used, and 22 TPI (in light metal) and more types. The pitch screws might differ from that. I think you better look up the AMC number in the Parts List and then try to source the screws. Our JSL mentions a few if you search there for "pinch".
According to this text:
http://www.team.net/www/morgan/tech/har ... bolts.html
the change from BS to UN(ified) began in 1965. That means "AF" spanners are needed from there on (indicated with AF or no letters at all). IIRC the BSA A65 has the new thread type. Your TR4 might be from before the switch.
Since you joined the forum not long ago you might not yet be aware of the wealth of info at archives.jampot.dk .

Albert

Re: Brit Bolts, nuts and fastners What ARE THEY? from US

Posted: Tue Nov 11, 2014 10:16 pm
by g80csp11

Re: Brit Bolts, nuts and fastners What ARE THEY? from US

Posted: Tue Nov 11, 2014 10:23 pm
by saltbox alf
Albert has actually given a very good concise reply. If you are used to whitworth, most of your spanners/wrenches / (I think that's the usa term)in Whitworth/ BS will be correct for the matchless.
We mostly have an adjustable wrench and a big hammer :rofl:

Welcome to the forum :beer:

Re: Brit Bolts, nuts and fastners What ARE THEY? from US

Posted: Tue Nov 11, 2014 10:37 pm
by JohnHewes
Get yourself a screw thread gauge to measure the threads per inch, something to measure the bolt diameter (a vernier or micrometer), and a book of thread charts to identify the threads.
That's what I have and I use them frequently, and sometimes I could not identify a thread otherwise.
In time you will build up a few tins with the various bolts in it and then all you need is to compare the one with the other.
Nowadays I need a small magnifying glass as well!

John

Re: Brit Bolts, nuts and fastners What ARE THEY? from US

Posted: Tue Nov 11, 2014 11:17 pm
by Rob Harknett
You will find most fittings are 26TPI cycle thread as advised. You can get them by pt. number from club spares. Later parts lists do not state sizes. Look at the part number, if it is between 000001 to 001000, drop the first zero's and replace them with STD, so you get a number between STD1 to STD 1000, now check the STD prefix number in a WD, 1940's or the likes of the 1954 master parts list. The latter perhaps the best as this converts old part numbers to new. These old books do give thread sizes etc.

Re: Brit Bolts, nuts and fastners What ARE THEY? from US

Posted: Wed Nov 12, 2014 11:28 am
by JohnHewes
Alf, is your adjustable Metric or Imperial?
John

Re: Brit Bolts, nuts and fastners What ARE THEY? from US

Posted: Wed Nov 12, 2014 12:00 pm
by Les Howard
As a general rule:

Nuts and bolts that hold steel parts together are BSCy (British Cycle thread) Generally these are 26TPI

Studs and bolts that go into Alloy are either Whitworth or BSF (BSF threads generally get coarser as the diameter increases) ...The coarser threads hold better in the softer alloy.

Studs can have Whitworth or BSF threads at the alloy fixing end and BSCY threads at the end that is holding the steel part.

BTW...The pinch bolts for the Norton Roadholder are usually studs and nuts NOT bolts...the nut end I think is 7/16 20TPI....RGM Motors will know.

There are Ebay sellers that sell MIXED bags of Bolts Nuts and washers in BSCY sizes and are Bright Zinc Plated (BZP) These are very good value and take the stress out of getting the right length. You might wish to buy Stainless stuff but although it will hardly ever corrode it is weaker than ordinary steel and much more expensive.

Les

Re: Brit Bolts, nuts and fastners What ARE THEY? from US

Posted: Wed Nov 12, 2014 5:07 pm
by Don Madden
Hello, Martin. You have received general info here on your question. As Technical Specialist of the North American Section of the AMOC I can offer help with more specific needs. Send an email or PM through the club & I'll respond with contact info. Just click on my name in the forum for links. I am located in Southern California. AMC did not fit Norton forks until 1964 on touring models & the scramblers always used the AMC type so don't know what you are needing, we can straighten it out directly. British Fasteners & Tools has an excellent discussion on hardware in the web site. ASA are very course threads, usually in mild steel, & not used on British bikes. Whitworth are also very coarse threads & BSC and SAE are fine threads & specify high strength steel. SAE is the basis for the later UNF threads used on some later British vehicles but the thread form differs. Cheers! Don.

Re: Brit Bolts, nuts and fastners What ARE THEY? from US

Posted: Wed Nov 12, 2014 7:17 pm
by saltbox alf
Hi John, I do seem to remember it was BSP originally, however held in left hand ,metric and right imperial :lol: