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Brass in wishbone jig, how much heat can it take?
blueshift - 11/1/07 at 04:26 PM

Hello folks, been a long time but I'm back in the garage and picking up the same problem that pissed me off months ago.

I made some bent top wishbones with a crap jig, have chopped and ressurected them as parts for new bones, now want to get it right.

Have pondered making a big bombproof jig that holds everything in place, but can't think how to make one that still gives me good access for welding.

So I think to myself, it doesn't really matter if the balljoint tube is a bit out of line, it will still be in the right place to within a couple of mil, it's the alignment and to a lesser extent the spacing of the bush tubes that matters.

So what I'm thinking of now is use my wooden jig to hold the parts while I tack them, then use the brass inserts and rod technique to hold the bush tubes in line (possibly mounted on a chunk of steel for more rigidity)

I know brass inserts have been used by folks here, my question is how much heat can they take, presumably you can weld tubes that they are inside.. what if I use lots of heat and the steel melts next to the brass?

also, I fancy using the technique of heating the bones cherry-red then putting in the oven to cool off (I seem to remember Mark Allanson did that with good results), will the brass handle the heat?

Nice to be back in the garage and back on here Hope everyone's builds are going better than mine..


3GEComponents - 11/1/07 at 04:33 PM

We often use a brass block behind flat plate when we plug holes, it leaves the underside flat, with little or no preperation required.


James - 11/1/07 at 04:40 PM

He's back!

Good to see you back on list.

Can I recommend doing the bush tubes from one long piece and then cutting out the middle section. This worked for me and they seem to be straight.

HTH,
James


flak monkey - 11/1/07 at 04:53 PM

Depending on the alloy, brass melts at 900 deg. Steel at 1600 ish. Cherry red in steel is anwhere from about 640 upwards IIRC. So you will be ok.

Its common when making neat welds to place a bit of copper or brass next to or under the weld as the weld wont stick to it, so dont worry about that either. Seen it done several times and they havent had any trouble.

David


blueshift - 11/1/07 at 04:57 PM

Cool, those are the kind of answers I was looking for, cheers. I'll bring a tube in tomorrow and go and see the engineering guy on the industrial estate.

James, you've finished your car! congrats, it looks really nice.

I would consider the cutting from a length of tube thing, but I've already got ones cut to size from GTS and all jigged up etc.


Volvorsport - 11/1/07 at 07:05 PM

aluminium is a good heat sink if you need to heat away from the area .

my jig involved clamping the bush tubes into placeon a simple T shaped jig , gives enough space to weld both sides enough before you take it out the jig and finish it off .


907 - 11/1/07 at 07:33 PM

Hi.

I made my jig as in the pic below.

Looks like I approached the task the opposite way to Volvorsport.

It proves there's more than one way to skin a cat.

Paul G Rescued attachment 22mm-w-b-jig-s.jpg
Rescued attachment 22mm-w-b-jig-s.jpg


NS Dev - 12/1/07 at 07:59 AM

brass will be fine, won't melt unless you get the whole bush tube orange.