Tig Aluminum to Steel?

[ichikuma]

I have a situation where I need to weld an aluminum gear to a steel shaft, is this possible with a tig welder? Is there any special filler metal I can use?

Thanks for any advice,

Craig

[wrench3047]

You should be able to solder it without any problems. Is there a woodruff key or something like that? I've seen solders with 40/50k tensile

[Billet Benny]

I have a situation where I need to weld an aluminum gear to a steel shaft, is this possible with a tig welder? Is there any special filler metal I can use?

Thanks for any advice,

Craig

Figure it out and you will be a rich rich man.. You can't fusion weld them... Solder/Brazing is the probably the only option short of keyways, splines, hardware, etc.

[ichikuma]

Thanks guys, I'll try and solder them together. The gear goes on a servo and I actually put a roll pin through it and it keeps snapping the roll pins. The servo drives the Z-Axis on a CNC machine I have and the head is really heavy which is why I think the torque is breaking the roll pins.

Thanks again for all the help,

Craig

[wb5jhy]

I don't think welding or brazing a gear to the shaft is a good idea. That would make future repairs, like replacing the gear, a lot more difficult. I know people with welders tend to think of welding solutions to repair problems but this situation calls for a machining solution. A full length key to withstand the torque and shock load and snap rings to retain the gear on the shaft would be a better solution. IMHO

[precisionworks]

Craig,

It sounds like the easiest solution is to broach a keyway in the gear & mill a matching keyway in the shaft.

Otherwise, you might want to try a solid steel pin instead of a hollow roll pin. They're much stronger & more difficult to shear.

[ichikuma]

Thanks guys for the machining advice. I don't have a way to broach a slot in the gear but a solid pin might be a good solution. One question on the solid pin is, how do I secure it from coming out?

You're right, I was only really thinking of a welding solution. I'm glad I posted this question, otherwise I might have done something not so wise

[imported_frank865]

You can get a broach from Enco...
http://www.use-enco.com/CGI/INSRIT?P...PMAKA=395-1112
And a bushing/shim...
http://www.use-enco.com/CGI/INPDFF?PMPAGE=84&PMCTLG=00
for $35-40 dollars.
HTH

[fun4now]

im new to tig and the only filler i have was a gift (and cut) but i always cut my OA filler and brazing rod, so i supose i would do the same with the TIG its just easyer to handle. if you are buying it by the LB and the $$$ is the same might just as well let them cut it for ya.

[Billet Benny]

Thanks guys for the machining advice. I don't have a way to broach a slot in the gear but a solid pin might be a good solution. One question on the solid pin is, how do I secure it from coming out?

You're right, I was only really thinking of a welding solution. I'm glad I posted this question, otherwise I might have done something not so wise

Get a solid pin that's a tight fit for the hole.. It shouldn't want to come out.. However, once it's in punch the lip of the hole (both sides of the hole i'd guess) to deform it so the pin cannot fall out.

[[email protected]]

Thanks guys, I'll try and solder them together. The gear goes on a servo and I actually put a roll pin through it and it keeps snapping the roll pins. The servo drives the Z-Axis on a CNC machine I have and the head is really heavy which is why I think the torque is breaking the roll pins.

What kind of CNC "machine"??? Mill, lathe, plasma, what? Did you build it or is it a factory machine?

If it's a factory machine, they put the roll pin in there as an engineered failure point. You need to recreate that arrangement exactly, otherwise you stand a **** good chance of breaking much more expensive things in the case of a Z axis overload or crash.

If you built the machine, then I'd go along with the solid pin in place of the roll pin. however, it HAS to be a press fit, not a slip fit. Something that small, all you need is .00025"-.0005" interference, but if you have a .0005" slip fit, eventually it'll beat the hole up, get loose, then you'll start losing positional accuracy on the Z. In this case, I'd also suggest programming with only G01 Z moves until you're confident the repair is going to hold up.

[Fred Smith]

seen it many times....

A steel endmill securely welded to a piece of aluminum.

[wrench3047]

if It was design to have a roll pin in it probably isn't suppose to have alot torque on it. I would try to figure out what is making it bind causing too much torque. Does it shear in the same area each time? It could have a bur. Solid pin would probably work a bit better but it would probably shear again or something else would break or shear. To hold the pin in place I would peen it ( use a center punch and dent the metal around the edges )