Author Topic: Tube Type &Gauge For Frame Repair??  (Read 627 times)

Offline Peter Gee

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Tube Type &Gauge For Frame Repair??
« on: 15.08. 2015 09:56 »
Hi Guys,

I have to replace a section of my 57 A7SS frame..the lower  left rail  that is badly creased from a previous guy running up a rock. Luckily the engine mount  dimensions are not effected.

I know A7/A10 frames are mild steel tube and welded, not brazed. But what s the SWG or AWG thickness of the tube?

 It measures OD  30.6 mm  (1 7/32) so 30 mm modern tube will do well and be unnoticed since I will join the cut with bulled-ted inserts, grooved to take the MIG weld.

Woiuld appreciate any thoughts and thickness dimensions.

Many Thanks

Peter G

Online bsa-bill

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Re: Tube Type &Gauge For Frame Repair??
« Reply #1 on: 15.08. 2015 10:48 »
good Question Peter, as time goes on will be needed more and an informative answer (as I'm sure is forthcoming) will help keep more of our beasts on the road
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline muskrat

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Re: Tube Type &Gauge For Frame Repair??
« Reply #2 on: 15.08. 2015 21:29 »
As yet no one has cut through their spare frame  *eek* to check the wall thickness. I'd guess at 2mm.
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Offline KiwiGF

  • Last had an A10 in 1976, in 2011 it was time for my 2nd one. It was the project from HELL (but I learned a lot....)
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Re: Tube Type &Gauge For Frame Repair??
« Reply #3 on: 16.08. 2015 21:04 »
I thought the frame was 1 1/8" o.d. X 1/8" wall?

If the o.d. Is measured near a bend it might appear to be a different size......

I'm not 100% certain of the wall thickness as I went to huge lengths with my battered frame to avoid cutting bits out, by removing dents and flattened bits using rounding "blocks", and filling any remaining imperfections with weld. The wall seemed that thick as it is so easy to weld, even with a diy arc/ stick welder.

Rocket Racer (aka Tim) on this forum will know the tube spec for sure as he built a replica rigid frame for his sidecar racer.
New Zealand

1956 A10 Golden Flash  (1st finished project)
1949 B31 rigid “400cc”  (2nd finished project)
1968 B44 Victor Special (3rd finished project)
2001 GL1800 Goldwing, well, the wife likes it
2007 KTM 950 Adventure, cos it’s 100% nuts

Offline Peter Gee

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Re: Tube Type &Gauge For Frame Repair??
« Reply #4 on: 17.08. 2015 14:36 »
Well I got 30.6~9 mm in several places which is 1" 7/32 nearest. 1 i/8th is for example  C12 C15 swinging arm guage..I know coz I have a piece and thought to use it until careful measurement showed it no be a little thinner OD.  30 mm x 4 mm should be good if one can find it. I doubt it was as thin as 2mm.