Tig Weld what went wrong and whats next

[CincyFlyer]

The more I think about this, the more I wonder why it was cracked in the first place. Are there more hidden injuries? I'd toss it in the scrap bucket; flying metal doesn't interest me.

 

[BeezFun]

I'd put that chuck in the same drawer where you keep your emergency home brain surgery kit, and go buy a new one.

 

[Big Barn]

Buy a new one. Use or give the cracked one to someone to use as a chuck on a small welding positioner.

Terry

 

[sandman2234]

I agree with the replacement suggestion, because it isn't only the balance, and the repair being right due to inexperience or the unknown metal, but why it originally failed, and by welding it you most likely decreased it's strength (which apparently wasn't good enough to start with).
Another thought... If the chuck originally failed with a 5 pound part in it spinning at 300 rpms, and you put a 10 pound part in it some years later after it has been repaired and spin it at 250 or even more, isn't it going to want to fail again?
I think that this is how people get hurt...
You go ahead and repair it, and only use it for a welding positioner although it still fits your lathe. After your death, your heirs sell the lathe and all of the attachments at your auction. The guy sorting the stuff for auction puts the repaired head in the lathe pile, not the welding pile. A novice buys it, and because he doesn't like the looks of your weld on "his new machine" fills and paints the weld so it looks good, and then he passes away. Your Son or Son in law buys it back because "it was yours". He spins the lathe chuck too fast, it comes apart and kills him. You get blamed for the death because somebody remembered that you repaired it.
Write this scenario any way you want to but none of it will be pretty.
David from jax

 

[MountainBuck]

I hear all of your concerns.

I do like the welding positioner idea.

Sandman, awesome creativity! Your right though, in a few years "I" will probably forget that I fixed it and chuck it up again so yea probably not worth keeping it around.

So the original reason it cracked is because it spun off the lathe and hit the concrete floor.

Heavily leaning to tossing it out in the garbage or some how making it not able to chuck into the lathe again.

However, I would still like to learn from it.

I think the comment about oil contamination is a real issue. I did not wipe the filler rod down. I did however grind the crack out but oil still could have existed.

Here is the last shot of this that is probably worth posting but I magnified the corner of the weld and the "X" is the base metal and the "Z" is the filler metal.

It sort of looks like to me that perhaps small pockets of something were bubbling out of the weld puddle?? Maybe this is the oil??

Just trying to learn something at this point. (other than home brain surgery! )

 

[yomax4]

All good advice above. I agree that it's probably not cast material but it could be slightly hard so I'd agree with the 309 or 312 stainless. Porosity is likely contamination or gas flow. You did use straight Argon i'm sure. I'd still vote to replace although I would have to look at it 1st and "maybe" i would fix it and use it if it were mine.

 

[MountainBuck]

Yes, I used straight argon. I wonder also about gas flow since it seemed the porosity is on one side of the fillet.

Another thought I had this afternoon was welding a "ring" of steel around the whole chuck. Not very thrilled with this idea since the diameter is an odd 5 5/8" which means I'd have to bend flat stock. Then maybe brazing the steel to the chuck.

Maybe an approach would be to tack into place then bend it around??

 

[tjflicek]

I've done a lot of oddball repairs like this. First off I believe Fowler is correct that this weldment is cast steel not cast iron. I would grind off as much as you can off what you already put on as the porosity will follow you out with what ever you do next.

Do the repair with 1/16'' silicon bronze filler rod at about 60 to 80 amps with straight argon at 20 to 25 cfm. Pre heating may help the welding procedure go a little faster, but I don't think it is critical for a good weld.

 

[sandman2234]

Mountain Buck,
What lathe is it off of?
David from jax

 

[Big Barn]

I'd put that chuck in the same drawer where you keep your emergency home brain surgery kit, and go buy a new one.

Thanks for posting that. It made me realize I didn’t have a brain surgery kit, so I whipped one up.



Terry