After a summer full of delays I finally got around to cutting the steel for my chassis yesterday... well I almost did. I lined the tube up carefully in the mechanical saw, let it go and CRACK! A badly made repair on the base gave way. It will not be useable until fixed either, so does anyone know a place I can take the saw base to get welded? It's cast iron or I'd have a crack at it meself. Preferably in the Bristol area but not too much of a prob.
A coupla pics of the problem:



[Edited on 28/9/09 by Badger_McLetcher]

could you not drill the base and bolt it together? If not have a go at welding it yourself. Strip it down, heat up the base, weld it then bury it in sand to allow slow cooling

If you're wanting to get on, then as a temporary measure could you get away with a pair of g-clamps around the jaws?

That's going to take some serious heating!!!

Never had any sucess with welding cast iron mysely as it always cracked either side of the weld. I'm told it can be brazed though anyone had any experoence?

Have you had a look at

http://www.mig-welding.co.uk/cast-iron.htm

???

I have successfully brazed a couple of cast iron wood planes before now, nowhere as big as that saw base though.

How about something like THESE PEOPLE do?





HTH

Neil

i think arc welding is needed for that isn't it?

Isnt MIG a form of arc? MMA?

Strap it together, but looks like the base / clamp has been overtightened. You'll lose accuracy with any repair.

Hmmm not too keen on attempting it myself- it's a bloody good saw apart from this. On top of that I got it for free so I'm willing to spend a bit of money on it.
A mechanical fix is pretty much out of the question due to the shape of the metal, though that metalock solution looks interesting.
Accuracy isn't too much of a problem, the clamp only prevents the outer jaw from moving- unfortunately there's no work around I can use to prevent this
Hopefully gonna take it to a place wednesday and they're gonna have a look at welding or brazing it for me. I may look at making some form of brace even once this repair is done to reinforce it.

We regularly patch castings at work if they have blow holes in.

AFAIK its done with cast iron rods in a stick welder. Dont bother heating them either, just grind out the area and weld away. You would never tell once they have been machined.

David

It could be arc welded, I used to work for a company that repaired castings etc and we would Vee it out , preheat it to 100c or so with a gas torch and then weld with cast rods.The secret is to weld a small area then peen the weld with a ball pein before welding another short section and repeating the process.When finally fully welded we would cover in old sacks or sand and allow it to cool slowly.
Paul

I've dont bits of cast welding with being an agric engineer, done with MMA welding (also just known as arc or stick welding, MIG is a form of arc but not suitable for cast). The rods for welding cast are fairly expensive, mabye £2-3 each & that's gonna take a few!.
As said pre heating & afterwards slow cooling help as the cast is nothing like as ductile & the localised thermal expansion & contraction makes cracking a problem.
As well as welding the crack up how about wrapping a length of flat mild steel bar right around the base, (about the depth of the base & 10-12mm thick?). It could be joined at the other end by a bit of threaded bar & tensioned up like a giant hose clip to give extra support. This could also be then welded to the base using the cast rods. Welding cast to mild steel does work but you still need the cast rods.
I repaired a 1 1/3" pipe bending former by welding up the cast & then filling in the gaps with sections of mild steel & it works fine!