Does anyone have a set of original WDM20 handlebars off the bike who can tell me the wall thickness of the tube used?..thanks...Ian

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

Hi Ian

I have an original broken in half set at the lock up - time permitting tomoro am, I'll bring with me !! We can measure at shepton

:-)

email (option): Jonnyob1@googlemail.com

Thanks John..I'm about to commission a batch and want to get them right..My M20 has bar end plugs fitted so difficult to measure without a lot of hassle....Ian

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

Ian, if it's any help, OE Norton bars are .085" (5/64")The wall thickness is greater than most recent bars.

Ian I just measured the bars on my special which I can only assume are originals. With a vernier I'm getting about .840". Is there an equivalent BSG size? 2mm would be close. Ron

email (option): ronpier@talk21.com

Count me in for two sets when finished.

email (option): britool51@hotmail.com

Hi Ian,
Put me down for 1 too . I have an old , seriously bent original, if you need I can cut the end off and measure the wall thiskness. .
Vince

email (option): vinver@ns.sympatico.ca

I too have an original set, but mine too have the plugs fitted but they seem pretty light, I'd guess at about 14 gauge, I used to make a lot of handlebars but lately I've noticed that a lot of the tubing I buy that I used to use for them seem to crease before they'll take the bends....probably made abroad!

email (option): davmax@ntlworld.com

Thanks for the replies..Tube wall thickness was measured using British Standard Wire Gauge (SWG) at the time the M20 was built. 14 SWG is .080" thick (2.03mm) and this appears to be the correct thickness.
I'll post on the forum when the bars are available....Ian

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

Ian, I saw you puzzling (and then editing !) over my earlier measurements. I was lazy and simply pressed the scale button on my thou / fraction digital vernier but of course it always rounds to 1/64"

Hi Rik..Yes, when you look at tube specifications you have to be careful not to mix up BSWG, Birmingham wire gauge and Stubbs wire gauge, American tube standards and the current BS standards which replaced BSWG...they all have similar, but different specs..
I realised after the initial post that I had got the gauge dimensions wrong and had to start again... ...Ian

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

I don't have to be careful Ian. I rely on people like you and Jan to supply me with quality parts.

The pattern (Cornucopia) bars that I have for the Norton have a notably thinner wall (metric tube ?) The trouble there is that the bar-end knobs fall out...

Thinner bars will do the job OK but I do worry about the possible detrimental effects on the amount of vibration if the 'sympathetic frequency' is altered by using thinner tube..(and further by the fact your bar end plugs have fallen out!)...Ian

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

Mine haven't fallen out, Ian. I found NOS genuine bars before the parts collecting was complete. Yet another one of my budget-inflating double purchases. I just meant to indicate that it is a consideration which not all pattern suppliers seem concerned about.

What size tube do you think you can obtain ? There must be a reason for using the heavy duty stuff, especially as they were clearly under pressure to reduce weight and demand on raw materials. It'll probably turn out that late-war bars are different from the 1940 examples.

I've read quite a lot of reports of pattern stainless steel bars on 1970s bikes folding up if the bikes fall off their stands. They tend to be horribly thin-walled.

Hi Rik...SWG tube is still available so the tube bender should be able to source the correct spec. It seems that whenever the Brits decide to standardise something there is so much old equipment still about that they have to maintain a supply of the original as well long after the introduction of the 'standardised' spec...and it becomes even more non standardised.
Thank God for British innefficiency and compromise...Ian

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