Threads

[fiatfan]

And I don´t mean the kind that I´m writing right now.... :wink: No, real ones, I wonder if there is a complete list somewhere of what threads in each place? I´d love to have the threads in whole engine/transm/gearbox written down so I know what tools I have to buy when I find bad threads, which I will....Thanks!
Tommy

 

[L.A.B.]

I wonder if there is a complete list somewhere of what threads in each place?

Not that I know of, but threads can often be identified by part number using this list: http://stainlessbits.com/link12a.html

 

[nickguzzi]

You may have your own suppliers lined up, but Tracytools - http://www.tracytools.com/ - has a wide range of threading stuff in Imperial in it's various guises.
They used to be present at many of the UK bike shows (maybe still are) but I think are mainly mailorder\internet.

 

[gripper]

When the Commando hit the market the motorcycle industry in UK were trying to move away from Whitworth based threads and come in line with the UK car industry. At that time this meant threads were Unified national fine (UNF) or Unified national coarse (UNC) these will use imperial size across the flats spanners (AF) These sizes were used on Commando frame and cycle parts. The engine and gearbox and forks however remained a combination of Whitworth, (BSW) British standard fine (BSF) and Cycle theads (BSC) BSW and BSF have a 55 degree thread form and the BSC has a 60 degree thread form. ( as a general rule, irrespective of diameter BSC are 26 TPI) these three systems utilise their own Whitworth based spanners designated by the diameter of the thread. Finally the Amal carbs and lucas contact breakers use British association (BA) with it's own spanners and a 47.5 degree thread form.

 

[kommando]

PM me your email address, I have a Excel which lists what tools are required for regular jobs so you can pull together o toolkit.

e.g.

Adjust clutch mechanism 3/4"AF socket Stubby flat blade screwdriver

 

[Deets55]

Old Britts parts diagrams have most of the thread sizes next to the part description.

 

[fiatfan]

I wonder if there is a complete list somewhere of what threads in each place?

Not that I know of, but threads can often be identified by part number using this list: http://stainlessbits.com/link12a.html

Thanks, I assume that´s the OEM numbers? Still doesn´t say what thread though, I mean f.ex. UNC, BSC, but really good help!
Tommy

 

[fiatfan]

Thanks everyone, I'll keep digging, but now I have a good start! In my view the best list would be like this, for example " timing cover, X number of bolts, with Y thread, contact breaker cover; 2 bolts, with Z thread" and so on. That I think would be a great help in the garage. Maybe finally I will have completed one.... 8)
Tommy

 

[kommando]

Sounds like you have just given yourself a job

 

[L.A.B.]

I wonder if there is a complete list somewhere of what threads in each place?

Not that I know of, but threads can often be identified by part number using this list: http://stainlessbits.com/link12a.html

Thanks, I assume that´s the OEM numbers? Still doesn´t say what thread though, I mean f.ex. UNC, BSC, but really good help!

It does give the thread type for many (third column). :?

A few BS threads were changed to Unified during Commando production, although not all, and different threads sometimes have the same TPI, for instance, many UNC and BSW have the same TPI although UNF is 60 degrees thread and BSW is 55 degrees, and after 40 years anything could have been changed or even replaced with metric fasteners, so I suggest you always double check as you go. In my opinion, no British bike tool kit is complete without sets of Whitworth, Unified and Metric (and perhaps also BA) thread gauges and a vernier caliper and after a while you begin to know what thread many of the fasteners are.

 

[gripper]

Strangely the screws for the Commando inlet manifold are 5/16 BSW, If you use 5/16 UNC they will probably fit but the socket for the allen key is a different size.

 

[gortnipper]

I wonder if there is a complete list somewhere of what threads in each place?

Not that I know of, but threads can often be identified by part number using this list: http://stainlessbits.com/link12a.html

Quite a few of these listing service are incorrect, as I discovered during my rebuild.

I guess I should have made note of these and published corrections, but alas I did not.

 

[fiatfan]

Kommando: +1!
LAB: Sorry for missing the "third column", was a little too fast for a change...
gortnipper: That sounds disturbing, but very good to know! Maybe I´ll remember to write the correct numbers down, fingers crossed... :wink:
gripper: That seems logical since the difference in the thread angle is just 5 degrees, should be tighter and less well fitting the longer the thread is though? Or am I thinking wrong, again? :idea:

 

[robs ss]

fiatfan
The attached list (I didn't complete it - best intents but poor follow through) is probably what you need.
I'm certain there are those on this forum more anal than me will have something similar - just have to figure how to extract it!
Then again - maybe not.
Cheers
Rob

 

[L.A.B.]

fiatfan
The attached list (I didn't complete it - best intents but poor follow through) is probably what you need.
I'm certain there are those on this forum more anal than me will have something similar - just have to figure how to extract it!
Then again - maybe not.
Cheers
Rob

"21, screw for gearbox inspection cover.....3/16" - 1/2"....Norton part 000450" is 2BA x 3/8".

https://andover-norton.co.uk/en/shop-details/14764

 

[SteveA]

fiatfan
The attached list (I didn't complete it - best intents but poor follow through) is probably what you need.
I'm certain there are those on this forum more anal than me will have something similar - just have to figure how to extract it!
Then again - maybe not.
Cheers
Rob

"21, screw for gearbox inspection cover.....3/16" - 1/2"....Norton part 000450" is 2BA x 3/8".

https://andover-norton.co.uk/en/shop-details/14764

I guess that response could be construed as a positive on your postulation regarding certainty! :shock:

 

[fiatfan]

fiatfan
The attached list (I didn't complete it - best intents but poor follow through) is probably what you need.
I'm certain there are those on this forum more anal than me will have something similar - just have to figure how to extract it!
Then again - maybe not.
Cheers
Rob

"21, screw for gearbox inspection cover.....3/16" - 1/2"....Norton part 000450" is 2BA x 3/8".

https://andover-norton.co.uk/en/shop-details/14764

I guess that response could be construed as a positive on your postulation regarding certainty! :shock:

Well there´s a lesson in English for someone who doesn´t have that as native language! I wonder about the "2BA", what does it stand for?
Tommy

 

[L.A.B.]

I wonder about the "2BA", what does it stand for?

= British Association:
https://en.wikipedia.org/wiki/British_A ... ew_threads
http://www.britishfasteners.com/threads/

 

[gortnipper]

gortnipper: That sounds disturbing, but very good to know! Maybe I´ll remember to write the correct numbers down, fingers crossed... :wink:
:

Most of the discrepencies were small - 1/4" longer bolts than required, etc. Two notables that I recall off the top of my head are that the oil junction block bolt and the allen heads on the fork lowers were incorrect diameters on the sheet.

 

[fiatfan]

I wonder about the "2BA", what does it stand for?

= British Association:
https://en.wikipedia.org/wiki/British_A ... ew_threads
http://www.britishfasteners.com/threads/

Just when I thought I was starting to get the hang of all these different threads, here comes another one.....does this never end? Thanks for the new (to me) info!
Tommy