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Bantam Frame Mods


wacky
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Sorry for yet another Bantam question but.......B175 frame:-

The cast iron lug wel.ded to the top of the frame at rear, the top mounting for the subframe. Is this welded to the frame or is it a lug joining the two sections of frame together?

I remember seeing an old film of frames being brazed together on a hearth using lugs and frame .sections being brazed in.

I don't want to grind it off and my frame fall in two bits! :blush:

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  • 3 weeks later...
 

Hi Guy's

The top subframe cast mounting, is just a hearth brazed sleeve over the tube. best way to remove it is to cut very gently with a 4'mini grinder nearly through the casting on both sides horizontally . then heat with oxy gas welding torch until the braze starts to melt now give the casting a sharp tap with hammer and chisel and the two parts of the casting should fall away. Heat and wire brush away the remainder of the brazing residue.

You will not effect the tube by heating as long has you do this before cutting out the bottom tube (if you are going too)I have found that the tube is 14 gauge ERW??

Pictures on the bsaotter web site.

The bottom hearth brazed lug does hold the seat and bottom tube run.

Sump shield ?? I would make your own 4-5-6 mm alloy sheet

Regards Charlie. www.bsaotter.com

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Hi Guy's

Hi Jon.

The first thing to do is to anneal the alloy, heat it up has hot as you dare and quench it.

This will make the alloy more workable for a short while.

I am spoilt now has I have the use of a fly press ,along with an hydraulic version .

But the first plates I made a long time ago ? Well a few years anyway.

With the use of a big vice, well bolted down, I might add,

I welded two lengths of about eight inches long x one inch and a quarter strong tube, to a long length of scaffold pole the gap big enough for the plate to sit between. The plate was clamped into the vice with steel reinforcing spacers, the power bar slotted on from one side and the bend gently formed. The side's if need be can then be for end in the same maner.

If you work the aluminium to much you will need to anneal it again ,as it soon hardens. OK

Regards Charlie. ...www.bsaotter.com

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