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BSA WM20 Base Nut Tommy Bar

There always seems to be variations to make life interesting.

What is the correct length of the tommy bar?

Rob

 photo bsa tommy_zpsjly4t80y.jpg

email (option): robmiller11(a)yahoo.co.uk

Re: BSA WM20 Base Nut Tommy Bar

Rob, if my perception is correct, original toolkit items supplied by the vehicle manufacturer did not bear the WD arrow head so I would suspect that the 6" version is more likely to be a standard LV7 part and not BSA specific but quite probably exactly what was supplied as a replacement for a damaged or missing item.

Do you have any M20 parts lists with the LV7 and 'Equipment to scale' inserts ? The Norton counterparts include quite a number of dimensions in the descriptions of the replacement items.

Re: BSA WM20 Base Nut Tommy Bar

Never really got to the bottom of this question so I thought I would have another go.

Rik you are quite right the broad arrow probably makes the short bar wrong even if it turns out to be the correct length.

It seems a bit of a waste issuing a tommy bar for a tool kit to use with just one box spanner, but the base nuts on an M20 are pretty difficult to get at so its obviously essential.

So does anyone know what is the proper length please?

Rob

tommy

email (option): robmiller11(a)yahoo.co.uk

Re: BSA WM20 Base Nut Tommy Bar

Trying it on the bike might make it clear which is the correct one...Ian

email (option): ian@wright52.plus.com

Re: BSA WM20 Base Nut Tommy Bar

That's a thought Ian but the angles are much the same and the extra length would obviously be better for leverage, but I'm not looking for the best one just the correct issue.

Rob

email (option): robmiller11(a)yahoo.co.uk

Re: BSA WM20 Base Nut Tommy Bar

Just an Idea... could it be a early/late thing with the latter one being shorter in order to save materials ?

This is just a theory, but there are many documented cases of items being re-designed/modified to use less materials as the war progressed.

Re: BSA WM20 Base Nut Tommy Bar

A valid question Wookie, arguably by reducing this tool in length by 1" could have saved 126,000 inches of steel bar during the wartime issue of BSA's. That's more than 3 kilometres.

Rob:smiley:

email (option): robmiller11(a)yahoo.co.uk

Re: BSA WM20 Base Nut Tommy Bar

Or alternatively, the short bar didn't have enough leverage/clearance so they lengthened it at some point...Ian

email (option): ian@wright52.plus.com

Re: BSA WM20 Base Nut Tommy Bar

Again that's possible Ian but its listed and pictured in the 1939 civilian spares list and it has the part number 29-9253. I think and I'm sure I will be corrected if I'm wrong that the "29" prefix on the part number means that it was produced for quite a long period prior to that, so if it was long enough leverage wise to do the job in 1939 or before it should still be in 1940 and after?

Most of the tool kit supplied by BSA for military M20s does seem to be pre war in design, perhaps if someone has one of these tommy bars with a piled arms stamped on it could be measured?

Rob

email (option): robmiller11(a)yahoo.co.uk

Re: BSA WM20 Base Nut Tommy Bar

Ian Wright
Or alternatively, the short bar didn't have enough leverage/clearance so they lengthened it at some point...Ian
Looking at the picture above the longer one is slightly bent so perhaps it has too much leverage... but I suppose it at least proves it's actually been used.

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