Anybody welded on a core bit shank?

[4570Man]

Unless you have a rotatable ground clamp, I'd refrain from doing it. Not my deal so I don't much care actually. Never happen on any lathe I own.

If it’s a newer lathe with digital instruments I agree it’s a bad idea. If it’s an older lathe without that stuff protect the bed from splatter and weld away. And put the ground clamp on the work piece.

 

[chim]

First thought I had was to cut the shanks and turn them to match the ID of a sleeve they'd both terminate in and weld the sleeve to the shanks. Don't know if it'd work or not, but it would help align the pieces.

 

[jwmorris]

I haven’t done any hammer bits but I have lengthened a lot of drill bits over the years. Have a number of fixtures for the task. Of course it’s easiest if the two pieces are the same diameter but it’s not a deal breaker if they are not.

 

[davisjt1977]

Actually there is. just ordered a Milwaukee one. Cheapest I found..$130. Have other bits to use it on. So we will put welding it on hold. I’ve already wrote off all these spline bits, so if this adapter holds up it could be a win. If not, we weld. I ain’t scared.

It is "I ain't skeered". (I think)

 

[Raul-02]

I have an old spline drive core bit. Milwaukee. My current rotary hammer is sds max. Thinking about buying a cheap sds bit from harbor freight and welding it on. I have no ideal what metal it is. Hard stuff. The shank is not replaceable on this one. Any advise?

If the bit is made from high speed steel ( any of the M grades) you can weld the living **** out of it and it'll be just fine; losing no hardness. Same with carbide. You can braze carbide and it suffers no harm.
If it's not HSS then you prolly didn't want to put it in your hammer drill anyway.

 

[TGM5040]

It would probably be easier to buy a spline drive to sds max adapter....

 

[yomax4]

Not sure how well it will work but there are Nickel Silver oxy-fuel rods "designed to extend hammer drill bits". Alignment would likely be critical. I've sold them in the past but never put them to the test for that purpose. Harris 14 and Weldcote Nickel Silver. Eutectic has one as well. Cool stuff that flows so thick you can braze overhead. I used to build small deer antlers with the stuff at shows.

 

[Hersheyfarm]

I got the Milwaukee adapter. It will work but adds a lot of length. One of my core bits already has a very long shank. I bet it adds another 8”.

 

[Tinhack]

I used to make special shapes out of drill rod then weld them to air hammer or power hammer shanks. I tried welding then re-heat treating after welding, but they always broke at the weld junction. Probably due to the high carbon content. That is, until I preheated both parts to yellow-hot before welding. I put a small tack weld(s) to hold them in place then heated. Weld them while yellow-hot. Let it cool before heat treating.