HELP welding a stub shaft

[Baby Grand]

You're really getting your money's worth out of that Dewalt!
It's too bad this thread isn't over on the welding forum - there are some very, very experienced welders lurking there.
Maybe you could start a thread over there, asking for some advice, and have a link to this thread?

 

[the old grind]

Need the bearing in place until the shaft is trued. My plan is remove the bearing after the shaft is welded to appx 1/2" diameter (?) Then weld on out to the 1-1/4" diameter (with the bearing in a safe deposit box).....

Substitute a v-block for the bearing (even crudely) when you spin it to check true after the fist few passes and it's cooled a bit. It only has to spin true to detect wobble/alignment and supporting any two journals ought to do ya. Can't burn a bearing that's already in the SD box.

Not a 'real' welder here, but I read recently that shaft repairs are sometimes done with different rods for root & finishing passes, say starting with 60xx's and finishing with 70xx's. The former builds up quick & easy (DC) without burning thru (that 1/2"), and the tougher outer stuff gives the strength where it's needed. (uh, like, "totally tubular")

I'm thinking ahead to how you would be able to clean up the finals weld passes and retain as much diameter as the bearing could be slipped past to reinstall. Yes, I'd really hate to depend on shielding of any kind to protect that vital piece during welding or finishing.

 

[Sodo]

OK guys I'm done. I think it was a total success. I was fairly **** about true-ing it up, and constructed something similar to what you wrote but using cartridge bearings for the v-block. Had to plug the keyway with a wood to roll smoothly on the cartridge bearing "v-block". The stub shaft I need is only 3 inches, just enough to hold a browning hub. Using a 20" long section helped a lot. The runout on the remaining stub is "almost" imperceptible. The real test is with a pulley on it spinning @ 780 RPM but I think it is about 1 or 2 hundredths.

I just used my wire-feed welder (Miller Multimatic 200). The welding wire is pretty tough stuff, I think harder than 7018 but thats just a seat-of-the pants guess (from bending the wire, & cutting it, and making a guess comparing it to 7018 rod).

I ran the welder on a 5,000W generator (on 220v). I was surprised and disappointed that the 5000w, 10HP generator could not run the welder on the 3/8" or 5/16" (thickness settings), I had to use 1/4" or the generator would pull down. But even so, since all the welding was on one spot on the shaft, the whole weld area was very hot, orange hot, very 'evenly heated'. I think I was a little lucky that it didn't sag and didn't seem to warp upon cooldown.

Here's some pics of the alignment and welding contraption. I was able to turn the shaft with one hand, while welding with the other hand. It was dicey, but due to the high heat in the area, the welds flattened out, and required very little grinding.

The original shaft was 1 inch where it broke. This new shaft (1.25) is 2.4 times strength of 1" shaft so I'm pretty sure my weld will hold. Also a 1.375 bearing has to slide over the shaft (&weld) to get to its land.

 

[Coyote machine]

Very Nice! Good work. Now slap that puppie back together and cut some grass!:cool2:

 

[dragoneggs]

Wow! Nice job. :thumbsup:

 

[Baby Grand]

Nice! Looks like your setup to spin the shaft and get it evenly heated (and cooled) really paid off.

 

[the old grind]

Nice move to use the stub's full (orig) length to help with alignment during the workup. I wouldn't expect a tad of radial runout to cause issues with the long belt, or to to be obvious with all the "shakin' goin' on."

Impressive jig/fixture work there, and good looking welds. :thumbsup: Take a bow, Sodo! It looks great! :drink:

 

[jimmysisson]

Just to add to the praises here. The jig with the bent braces to allow room to weld and adjustability for truing is very clever. As a former carpenter I like the wood jig and keyway filler, too. Nice welds, and best of luck with the mowing.
Jim

 

[Big Barn]

Great work. I like the 'set up'. Good thinking too!!

Terry

 

[Sodo]

thanks guys

 

[Sodo]

You're really getting your money's worth out of that Dewalt!
It's too bad this thread isn't over on the welding forum - there are some very, very experienced welders lurking there.
Maybe you could start a thread over there, asking for some advice, and have a link to this thread?

Not sure why I posted here instead of the welding forum. I've been there before. One thing I noticed on forums is the more experienced a guy is the more "you can't do that" advice you get. There's a lot of fellas out there with less experience but enough smarts and far more enthusiasm to get it done, thats who I wanted help from. Experience is important but I think some of those old guys who could tackle anything in their younger days have become too pessimistic to make things happen anymore if ya know what I mean. You have to have a positive goal in mind, if you don't have that you are going to fail from the getgo. Not a surprise, thats pretty much how the world works actually, you think negative you will fail and you're doing that to yourself.

Anyway thanks for all the kudos, I've patted myself on the back a few times too. I walk over and look at that shaft as if it's the first time I saw it, its sure beautiful thing! Still a little surprised something didn't go wrong. In fact I held off buying any further parts waiting for the "success" of this step. (the reluctant optimist). I didn't win out "in time", it took me all day, if billed out at $95/hour it would be an $800 repair. But with my new "experience" I could do it again much faster.

 

[pmsmechanic]

I'm impressed! Well done and who cares how much time you spent on the job. You are that much wiser now for the next job and sometimes there's no point in putting a price on gaining wisdom.

"Not sure why I posted here instead of the welding forum. I've been there before. One thing I noticed on forums is the more experienced a guy is the more "you can't do that" advice you get. There's a lot of fellas out there with less experience but enough smarts and far more enthusiasm to get it done, thats who I wanted help from. Experience is important but I think some of those old guys who could tackle anything in their younger days have become too pessimistic to make things happen anymore if ya know what I mean. You have to have a positive goal in mind, if you don't have that you are going to fail from the getgo. Not a surprise, thats pretty much how the world works actually, you think negative you will fail and you're doing that to yourself."

In regards to the above quote I often say that it's amazing what you can do when you don't know that you can't do it.

 

[Sodo]

Started mowing yesterday, the mower is quiet & smooth. I like it! Have a little pulley wobble, will try to measure it after the mowing is done. I'm about 3 weeks late, the grass is thick. I'll say there's quite a lot to learn for a first-time mower.

 

[Coyote machine]

Cool! Any pics of it on the tractor? How'd it do with the thick grass? Are you getting the finished cut you're looking for?