Loader Bucket Build

[jb1390]

I'm building a new bucket for my Mahindra. The stock bucket was too small, and I wasn't completely happy with any of the options for prebuilt buckets I found. Saved some money by building my own, and I believe I'm getting a much better final product.

The structural material is Hardox 450, I had much of it sheared to size at my local steel supplier before I picked it up. This stuff is crazy strong, but will bend before breaking so it's a good choice for a bucket material.

 

[jb1390]

Before I welded the bucket together, I did some research on welding Hardox. The bottom and sides of the bucket are 1/4", the rear and top are 3/16". The manufacturer does not recommend preheat for material this thin, which was definitely a time saver. They also recommend a filler material of 70 KSI or lower to prevent cracking. I welded using my Hobart 230 with ER70S-6 wire.

I also did a butt weld test with a small piece of 3/16", ground the welds flat and bent it to ensure the sample was free of cracks.

 

[jb1390]

The addition of a plate in the lower rear of the bucket is necessary to increase torsional strength. As a comparison, using Solidworks, a 100 pound load placed on one corner, with the opposite edge restrained, resulted in a deflection of 1.5", from the bucket twisting. The addition of a plate reduces that deflection to less than .050". The real world results confirmed this.

 

[jb1390]

I could not see the cutting edge from the tractor seat when the bucket was rolled back all the way, so I trimmed 2" off the top lip and adjusted the sides as well.

 

[jb1390]

Bucket looks pretty big from this angle.

It's 34" deep, 79" wide, and 26-27" high.

 

[sdef]

Nice looking job. I recently purchased my first good welder, a Millermatic 211, and hope to start using it and becoming reasonably proficient in the foreseeable future.

 

[jb1390]

I had some issues when welding the cutting edge on the back, due to lack of heat and possibly some hydrogen embrittlement. Each weld on the back let go over a 30-40 minute period after welding. I had clamped the edge to the bottom, to close the small gap that existed, which is why the welds were under stress.

Without knowing exactly what material the cutting edge was made from, had to do some guesswork. I think it's an AR400, but the place I bought it from couldn't tell me.

2nd time through, the cutting edge got 150 degree preheat with oxy acetylene, and the welds got postheat with a mapp gas torch for a minute or two. This combined with some higher settings resulted in no cracks.

I waited about a half hour after stitching the edge to ensure I didn't hear any popping, then welded it full.

For reference, cutting edge is a 6" by 3/4" thick piece.

 

[jb1390]

Added wear plates to the bottom because they look cool and add a little strength and durability. I seriously doubt that 175 KSI 1/4" material will ever wear out on my 50 HP tractor.

 

[jb1390]

Did multiple passes to attach the mount plate, as well as multiple passes to build up the bead at the corner by the cutting edge. Too much heat will soften the Hardox, so keeping the settings somewhere in the middle of the machines capability and multiple passes where required seemed to work best.

 

[jb1390]

3 chain hooks on the top lip, and a D-Ring with chain hook on the inside of the bucket in the middle. The top lip is also reinforced in a triangular shape, similar to the bottom rear but not as exaggerated. It tapers from 3/8" (two 3/16" sheets side by side), to about a 2.5" thick section where it meets the rear of the bucket. It should keep the top lip from bending under a chained load for sure. Anything really heavy will use the inner chain hook anyway.

Wire wheeled the welds to remove slight oxide layer, carbon and copper, and sprayed primer on the clean metal. The hardox comes with a primer, so unless I ground it off I left it alone.

Only thing left now is some black rustoleum paint, then I'll put it to the test.