Is this a candidate for a cast iron rod repair?

[RonA]

Hi all,
I recently lent my mortise attachment, which fits on my pillar drill to my neighbour. The collar on his pillar drill is smaller than that on mine & despite the attachment coming with a distance ring for differing collar sizes, the inevitable happened & he snapped the lug off the attachment.
He offered to buy me a replacement but I am reluctant to accept as the attachment now costs (over £50) & he helps me out as we operate a sort of tool library between us.
Could the lug be welded back on using cast iron arc welding rods, note I don't have access to preheating gear other than a butane powered paint stripping torch.
Thanks in anticipation
RonA

 

[Digger6135]

That could possibly be a brazed repair, but you would need a much better heat source.

Digger6135

 

[piman]

Hello Ron,

if you vee the inside diameter I think it's worth a try. perhaps with a couple of washers in the gap to hold it as near as possible to being true with the clamping bolt.

It didn't help that the notch for the clamping bolt and nut was machined with a square ended cuttter, perfect stress riser.

Alec

 

[Bill Edwards]

Is it actually cast iron?

I would think it cast steel instead, and that would be easier to repair.
Touch it with a grinder, if the sparks are red it is cast. But cast iron wouldn't seem like the material of choice for something that has to be clamped on like that, hence my mentioning it.

 

[RonA]

Is it actually cast iron?

I would think it cast steel instead, and that would be easier to repair.
Touch it with a grinder, if the sparks are red it is cast. But cast iron wouldn't seem like the material of choice for something that has to be clamped on like that, hence my mentioning it.

No it's definitely cast iron, the lug has a lovely crystalline fracture across it
RonA

 

[Bill Edwards]

Well if you're sure, it's just I have often seen cast steel and iron mixed up so thought I should ask, as the spark test never seems to fail.

If you had some fire bricks and Oxy/acet it might be possible to braze it, as it is I think your best, or only, approach would be to stick weld it with proper cast rods (high nickel content).
V it out, clamp it so it's held rigid and do it in small amounts so the part never gets too warm to hold in your hand. And peen the weld as it cools.

 

[brightspark]

that would braze up no bother with oxy acet and heat all round with a propane torch

 

[Bill Edwards]

That's why I mentioned bricks - surround it and heat with the gas torch then braze with O/A - or do it all carefully with O/A.

But without O/A it'll have to me done with stick welding, and I wouldn't try that hot.

 

[brightspark]

it looks a bit thin for stick welding. probably burn it away if it was me id probably braze the bolt in on the end as well as it doesnt look as it needs to be removed

 

[Bill Edwards]

Hmm, there are welders and welders!
I've amazed myself at how thin and small some things I've stick welded are. It's not easy and it's not fun, but you can normally do it with care.

My local supplier only does cast welding rods in 3.2mm, but you should be able to get them in 2.5 which will help.

 

[dannyp]

personaly i'd braze it if given the choice, probaly would weld

 

[Rrunnach]

As already mentioned, clamp is more than likely cast steel, which has a crystalline structure, too. Quick hit with a grinder will confirm for sure.