Frame -SAE 1020 hot-rolled tube Carbonium steel

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At the nuclear plant (the same one with the Lister diesels) we had x-ray diffraction equipment for verifying materials. This became a big deal in the industry after several plants, ours included, would up installing forged Chinese piping components. Anyway, I took my '71 Commando frame into the plant before welding on it just to be sure. The verdict: SAE 1020 hot-rolled tube, similar to ASTM A-36 structural steel. Commando frames are plain old carbonium steel. Weld with E-6010 or E-7018 electrodes (SMAW process) or ER-70S-2 filler material (TIG process).

Mark Smith
 
Yep, I always wondered where the myth that Commando frames were high tensile steel came from. Jim
 
Its wasn't me. Apparently only the '67-68 Cheetah 45 scrambler had 4130 chrome moly frame. its been called steel on steroids and w/o isolastics it needed to be.
 
Norton race frames for the Manx models were all in Reynolds 531 tubing. Going back quite a ways in history, to the old lugged garden gate frames just postwar. The quick and dirty test for it is you flick it with your fingernail, it goes "ting". Everything else pretty much goes "clunk", although being thin-walled the Commando frames have a lighter clunk....

Hope folks picked up that that "carbonium" was a joke, carbon steel is carbon steel.

Cheers.
 
I rather liked the carbonium frame idea. I now have a new line to tell the HD riders. Jim :D
 
Ugh I didn't know the term was a spoof, ugh, I'm such a green horn yet.

I think/feel/depended on plain thin tube steel to save me on Peel when entering upper zones of phase 2 handling and then onward into 3 more higher loaded faster handling phases. My sense of it is both articulated relief/alignment and self dampening of frequencies transmitted into tire contacts - but only at rates and loads exceeding what is seen in elite computer controlled corner cripples - that ring and buzz right out of adhesion and so must cut power and loads to get safely upright again to use their straight line sprinting ability. There also seems to be an innate advantage in Commando CoG - as other configurations tend to resist staying learned over or tend to resist coming back up - ugh. I gave up trying to over come tank slapper onsets holding moderns down or getting them back up in time, when chassis frequency matches tire hysteria, game over.
My sense of Peel is wild loads of road-wind/pilot inputs pass through like wind in a flag instead of bull whip snapping its end off. Un tamed isolastics can't take ya there, beware.

Thin big steel structures can be made lighter stronger than thick Al components as can be found in both fork yokes and connecting rods. So plain Jane obsolete steel frame is another of Peel's raw rubs to the hi end backwards wonders.
 
So it looks like carbonium could be an amalgam , some of the harder to find parts were made of unobtainium.
 
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