Lawnmower Handle Repair...advice?

Hello permies. I am fixing up a lawnmower for my friend with my new flux core welder. The handle snapped close to the base of the mower. He had it rigged up with some pipe clamps and a steel rod which was a good temporary fix, but he brought it to me to make it a bit more permanent.

Tonight I cut the broken ends off and cleaned up with my grinder. Now I have some options to repair it. To start, the handle is 3/4" diameter (outside) with 1/16" wall thickness. I have two possible repair parts. One my friend brought with him when he brought the mower to me. It is 1" outside diameter and 1/16" wall thickness. He thought I could make it a sleeve of sorts - put it over the handle and weld it to stronger steel further from the break. The other option is some scrap pipe I have from my cargo bike. It is 3/4" outside diameter but it is 1/8" wall thickness, so far stronger than the 1/16" of the handle. With that I could just cut a piece to fit and weld the two ends in.

I'll put photos so it's easier to see what I'm talking about.

Any advice is appreciated. I know if I go with the thicker one I'll focus the heat more on it than the handle when welding. Opinions welcome! I have until this coming Friday to have it fixed up for him because he uses it for his property maintenance business and the lawn mowing season is about to begin.

To repair, it might be useful to identify the forces that caused the failure in the first place. Was it an upward thrust or a downward thrust? How can you reinforce the pipe to spread out those stresses?

Personally before any welding, I would drill through and fasten with a bolt. And then observe the wear and tear -- a diagnostic approach.

I know, I know, not nearly as cool as laying down molten steel.

For commercial (ab)use, I'd go for the heavier one.

Douglas Alpenstock wrote:
To repair, it might be useful to identify the forces that caused the failure in the first place. Was it an upward thrust or a downward thrust? How can you reinforce the pipe to spread out those stresses?

Personally before any welding, I would drill through and fasten with a bolt. And then observe the wear and tear -- a diagnostic approach.

I know, I know, not nearly as cool as laying down molten steel.

He's a speedy responder. I just texted him and he said it was wear and tear of going over bumpy lawns and transfers , and it broke in a vertical motion.

Now I am thinking I could use both pipes. Do a butt joint with my 1/8" wall pipe, then do a sleeve of sorts over the two butt joints with the 1/16" wall stuff. Just an idea.

I would take time to more time to explore, but I work most days this week + school, so I'm going to see if I can get this done Monday or Tuesday night. I'll ask my welding profs too for their thoughts on it.

Pearl Sutton wrote:
For commercial (ab)use, I'd go for the heavier one.

Yeah I'm leaning that way too.

Thanks folks!

Unless you are pretty darned good at welding, I think the thicker piece will be weaker.  With that arrangement, all the load of the "up and down" will be on your welds.  And that load will be concentrated at the top and bottom of each circle of your weld.  Not much room for error.

I'd go with the sleeve myself.  It will spread the load back to virgin metal and it's naturally stronger based on it's larger size.  I'd make it at least 6" longer than the gap you're filling so it overlaps 3" on each end.  

Doing both solutions might be even better but it's probably a lot more work and might not be that much better.

Mike Haasl wrote:Unless you are pretty darned good at welding, I think the thicker piece will be weaker.  With that arrangement, all the load of the "up and down" will be on your welds.  And that load will be concentrated at the top and bottom of each circle of your weld.  Not much room for error.

I'd go with the sleeve myself.  It will spread the load back to virgin metal and it's naturally stronger based on it's larger size.  I'd make it at least 6" longer than the gap you're filling so it overlaps 3" on each end.  

Doing both solutions might be even better but it's probably a lot more work and might not be that much better.

I am a certified alright at welder in my opinion, so the sleeve option would probably work better for my skills. Welding two of the same thicknesses together is easier than different ones, at least for me.

I'll get my welding profs' opinions tomorrow too. Thanks!

An interesting thought might be to use the other piece to reinforce the other side, so it has both of the at risk areas sturdier. Might make the mower useful longer. If one side broke, the matching point is probably irritated and likely to go next.

Pearl Sutton wrote:An interesting thought might be to use the other piece to reinforce the other side, so it has both of the at risk areas sturdier. Might make the mower useful longer. If one side broke, the matching point is probably irritated and likely to go next.

Good point Pearl I can ask if he wants me to do that.