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[Patrick Wang]

I am a apt TIG welder myself, I have mostly had my experience welding aluminum frames together.

Knowing that the heat from the welder is going to bend the shaft if you keep the heat on too long, does anyone have advise as to the proper way of welding a gear to a shaft and how much weldment you actually need.

Two years ago, we tried to build a ball grabbing device with welded sprokets onto drill rod. (This is probably a bad basis for judgement because the design was flawed from the start had, 16 in of unsupported rod) but we had the drill rod shear. Now, I don't believe that a shear would be because of the weakening from the weld, if anything I'd think it was bend out if the drill rod was warped from heat.

Basically what I am looking for is someone to tell me that there is a way to weld a gear/sproket to a shaft without damaging the shaft. And how great are the benifits? (it seems that the little weldment just intuitively would offer a lesser degree of maximum torque than a key or pin)

Thanks again for all the replies

[Matt Reiland]

The UAW welder that helps our team out has a few tricks that make his welds clean and very strong.

I would think (this comes from an electrical guy) that if you are shearing a shaft that the shaft size needs to go up some? For our boom this year the final stage was 1/2" shaft with 20pitch Boston gears that took huge abuse and never had any problems, of course it was also supported well with bearings.

In the past when we used keyways and pins, cutting the keyway into the shaft took away a substantial amount of material and if cut incorrectly could put extra stress on the shaft according to one of our mechainical engineers.

For our gears, we usually chamfered the inside bore of the gear to allow the weld to make a nice contact at that point, also we sized everything for a very tight fit without the weld. The welder has a little tool kindof like a drill facing upward with a foot pedal that spins the shaft while he welds to make a nice continous bead around the shaft. Also he has a tub of some purple stuff that looks like playdoh that absorbs heat off the materials so it doesn't deform as much. Properly welded gearing makes for a very strong geartrain.

Also we lightened all of the gears to a great degree (some as much as 80%) as a note to all teams: lighten the steel first its a much bigger bang for the buck!

[Patrick Wang]

Looks like I'll have to be resourceful if we want to weld the gears We've got a TIG welder, a table and a 90 degree jig.

Thanks anyways for the information, we may just try and experiment with welding gears/sprokets, see how it turns out.

I've been trying to stay away from that 1/2 in shaft, the bearings start to take up a lot of room and the shaft becomes very heavy very quickly. (too bad you can't lighten the drill rod)

Thanks again for all the replies, and good luck with all your teams next year.

[sanddrag]

Well, there just might be a resourcefulness award next season. As for the 1/2 inch shaft, were you refering to when I said 3/4 keyway shaft turned down to 1/2 inch on the ends to fit 1/2 in. bearings? An alternative would be to do smaller skyway wheels with 1/2in. bore keyway hubs and use 1/2 keyway shaft for the axles turned down to 3/8 on the ends for 3/8 bearings. The only real downside is that I don't think skyway has the really big wheels with the 1/2 inch hubs. Our 10x3 beadlocks came with 3/4 inch keyway hubs.

I hope this wasn't too confusing.

I'm not sure what you mean by "drill rod" but you can lighten any shaft/rod by using a lathe to turn it down or drill out the center.

Yeah, I've made another meaningful post.