So I was digging up a stump the other day when I heard a loud bang, after which my bucket hung in an obviously out-of-spec way. I somehow broke one of my bucket pins!
I was in the middle of something so I pulled the pin out, sledge-hammered the bent bucket ear into submission, welded the pin back together, and got back to work.
That got me maybe an hour before my welds broke. That isn't terribly surprising because this is a thick, solid pin and my welder is really most at home on 3/16" plate or less. Still, it was worth a try.
I didn't even bother pricing a replacement pin. This is a gray-market Kobelco excavator, and parts are heinously expensive (if you can even get them). Plus, it's just a steel pin with a few very basic features. Fabricating a new one ought to be easy.
After a little hunting I was a little disappointed in the grades of steel I was able to find in this size. I was really hoping for a nice hard tool-steel blank or drill-rod or something, but struck out at all my sources. The best I could do was 1-3/8" diameter 4140 chromoly steel pre-hardened up to Rockwell C 28. That's probably a fair bit softer and weaker than the original pin, but it was the best I could do and my excavator was more-or-less useless without this pin, so I ordered it. I figured when I made the new pin, I'd be omitting the grease hole, so hopefully eliminating that stress concentration would make up for the reduced strength.
Once the bar arrived I got to work and made a replacement pin. I also drilled out the excavator link for a new grease fitting (since it used to grease through the center of the pin). What I didn't do is check to make sure they sent me the right thing. When I went to go install my shiny new pin, it didn't fit. They sent 1-7/16" bar, not the 1-3/8" that I ordered. Bummer.
Luckily their sales department was suitably apologetic and shipped out a new bar straight away. I made another pin (one that actually fit), and I was off to the races.
And I can tell you that it has held up wonderfully. I've had this pin in service for months now and have not been kind to it, and it's still in once piece. In fact, a little while after I filmed this footage, I broke the other original bucket pin and had to fab up a second home-made pin just like this one. They're both working great.
27 июл 2024
