Need Help- Trying To Make Bucket Pins For Excavator-

B

Bob V

H-M Supporter - Gold Member
H-M Supporter Gold Member
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Apr 21, 2015
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Hi,
I'm going to try to make some bucket pins for my CAT 314LCR excavator.
I called CAT-- and they told me the pins are very hard- much harder than the bushings they ride in (this was different information than I had heard!)
Anyways, I found some 4140 65mm Quenched and Tempered rod available online--it's expensive but much less than CAT charges for their bucket and other excavator pins.
-- so I was thinking of buying some of this 4140 rod stock, cutting it to length with my band saw, and drilling holes in the end for bolts to hold it in place on the machine.
Question: this material (4140 quenched and tempered rod) has a Brinnel hardness of 294 which the seller (Parker Steel) tells me is equivalent to Rockwell 28-30. --- Can I cut this stuff with my bandsaw and drill it HSS drills?
Thanks in advance,
Bob
 
I have successfully cut Cat pins. Use a good bi-metal blade on your bandsaw. Slow speed and as much pressure as your saw will take. It should drill & tap OK. Keep the feed pressure up so it doesn't work harden.
 
I cut that stuff all the time on my 4 x 6 bandsaw. Don't say what diameter the material is, I use a 10-14 vary tooth bimetal blade on my saw most of the time. I cut dry with the saw in the lowest speed.
I made a set of pins for my neighbor last year for his bucket loader. He hasn't complained either. Better not, I haven't billed him for them either!
 
That's the bread and butter of the oilfield. I would only add that if you have to turn it down, and you should to get a smooth surface, and you are using HSS on the lathe, get under the mill scale with the first cut. Besides, it's not all that hard right at the surface. But that hot roll crust can be rough on your HSS tool. By all means, if you have carbide for your lathe, use it. If you actually need a finished size of 65mm, you may want to back up an look at your plans again, unless that is TG&P rod you are buying. Most of it will come hot rolled and rough.
 
Thanks to everybody--
Tony, and everyone else:
It turns out the 65mm 4041 Quenched and Tempered rod is 87 bucks a foot!
Can I just use 2.75" 4041 rod (about 15 bucks/foot), and turn it down on my lathe and drill it? --Does it have to be Quenched and Tempered?
 
For that application I would not use as-rolled, or normalized. Q&T is the correct condition. That price sounds out of line. Shop around. I'd sell you all you wanted for that price.

Or look into 4340 Q&T, or even 4130 Q&T. Those will work fine, and maybe you can find something on ebay that's a decent price.
 
Thanks again, Tony,
Is that Q&T process all the way through the rod-- or is it like "case harden" (just on the surface I think!). I'm asking so I know if I turn it on the lathe will I end up with a softer surface than the Q&T.
Thanks--
 
It is considered a "through hardening" treatment. Although the ASTM testing procedure calls for the hardness to be checked "mid-radius", that is, on the face of a cut piece halfway between the OD and the center. This is to ensure that the quenching temperature is held long enough (soak time) to get the bar up to temp all the way through. You can expect the piece to be a little softer in the dead center than it is near the OD, but not so close to the OD that you are getting readings in the decarb layer. That's why you usually will see a fairly deep grind mark on the OD of a bar where the hardness it tested. In the decarb layer, you will see low readings that are not truly representative of the bar's true hardness. The mid radius tests are what you will see on the MTR's, if the suppliers furnish them.
 
Wow! A lesson in metallurgy. Thanks Tony. This forum is the best--
 
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