Best Steel for Backhoe Pins/Bushings

[LD1]

I have the capability to make my own pins and bushings. Will eventually do all of them on the BH, But am going to start with the swing pins/bushings for now, since they are the worst.

I know the OEM ones are extremely hard. Rc 58-60 or so.

I have googled and there is a ton of reading. But I figured I'd get the opinions of members here.

Currently looking at the either 4140, or 1144 stressproof.

McMaster-Carr

McMaster-Carr

Price for a 6' stick is about the same. $112 for 1144 and $120 for pre-hardned 4140.

A lot of the reading I was doing was mentioning the 4140 as a good pin/bushing material. But it is only hardned to the rc30 range and cant be hardned much more. The 1144 is just a tad softer but "can" be hardned a lot more.

Yield strengths are about the same.

Not sure on what would be best? or is there something else that is as affordable?? I dont want to break the bank here. Just looking for suggestions at the moment.

 

[Kyle_in_Tex]

I may be wrong, but I'm thinking you are a bit high on your Rockwell #'s. Once it gets above around 45Rc, you can only cut it with really good tooling, think carbide. Plus, it gets brittle and can crack around weld joints.

I have to admit, bushing repairs are not my "forte". How do they get the old bushings out if welded? Or do they just bore them oversize? Do they use softer material for the pins so that the bushings don't wear? It would seem that a few grease grooves could go along way if properly greased.

I have a buddy with a VERY wore out backhoe that needs a bunch of new pins/bushings. I would think a good bushing around 45Rc and a softer pin maybe around 32Rc would be good???

When I bought my post hole digger, the bushing and pin were hopelessly rusted together. I had to drill out in steps the pin to finally remove the shell of it. I was thankful that it was soft steel. I made one with a grease hole in the middle and a zerk. I used 17-4 stainless and heat treated it to about 42Rc.

 

[Recoveryhill]

All the pins we machined for production buckets and booms were cold rolled carbon steel. The pins were regarded as the wear component to protect the bushings. Cold rolled shaft machines well and is relatively inexpensive. Air arcing out worn bushings, machining, welding back in place and line boring is not. The harder the pin, the more likely wear on the bushing is going to be.

1018 is one, 12L14 has greater tensile strength and is free machining or 1144, the strongest of the three but still easy to turn.

Plenty grease is your friend, and some new pins, from time to time.

 

[Recoveryhill]

1018 = Rockwell B71
1144 = Rockwell B95
12L14= Rockwell B84

4140 either pre-heat treated or soft is usually sold for high strength shafts, either hot rolled or ground and polished. I wouldn't use it for pins.

Pins in buckets and booms and the like are not a high strength application. They provide a connection and a pivot point, that's all. I frankly don't know if I've ever seen a pin in that application sheared, even when they were worn all to heck.

Just say'in

 

[LD1]

I may be wrong, but I'm thinking you are a bit high on your Rockwell #'s. Once it gets above around 45Rc, you can only cut it with really good tooling, think carbide. Plus, it gets brittle and can crack around weld joints.58 for the pins and 60 on the bushings is what they rockwelled when we re-did pins and bushings on dads 4500 backhoe. So thats all I am going off of. He ised 4140 because that is what he had avaliable. But since 1144 is ~ the same price, if it is better, that is what I will use.

I have to admit, bushing repairs are not my "forte". How do they get the old bushings out if welded? Or do they just bore them oversize? Do they use softer material for the pins so that the bushings don't wear? It would seem that a few grease grooves could go along way if properly greased. bushings are NOT welded in. There is a bore, and a pressed in bushing. Some of them (the thin-walled ones) are split/spring bushings

I have a buddy with a VERY wore out backhoe that needs a bunch of new pins/bushings. I would think a good bushing around 45Rc and a softer pin maybe around 32Rc would be good???Yes, I am thinking I want the pin a bit softer as well. It is easier to replace the pins than the bushings on a BH. But I have no way to heat treat short of just using a torch and dunking in water:confused2: That is why I am considering the PRE-hardened 4140 @ ~rc30, or the 1144 @ ~rc26

All the pins we machined for production buckets and booms were cold rolled carbon steel.But WHAT kind of carbon steel?? 1144 is a crabon steel. As is 1045, 1117, 1215, 12l14, etc. And there is a big difference in the strengths and hardness' of them. The pins were regarded as the wear component to protect the bushings. Cold rolled shaft machines well and is relatively inexpensive. Air arcing out worn bushings, machining, welding back in place and line boring is not. They are not welded bushings. They are pressed in bushings. No need to cut out, weld, and line bore unless the pin chews clear through the bushing and works on the bore a good bit. The harder the pin, the more likely wear on the bushing is going to be.

1018 is one, 12L14 has greater tensile strength and is free machining or 1144, the strongest of the three but still easy to turn.

Plenty grease is your friend, and some new pins, from time to time.Yes...I am not stingy with grease:laughing: But I dont want bent pins either. That is why I want something somewhat hard and strong

1018 = Rockwell B71
1144 = Rockwell B95
12L14= Rockwell B84

Not sure how the B scale compares with the C scale, but according to mcmastercarr, the 1144 "stressproof" is Rc 24-24 w/100,000 psi yield.

4140 either pre-heat treated or soft is usually sold for high strength shafts, either hot rolled or ground and polished. I wouldn't use it for pins. 4140 seems to get the most reccomendations amoung what searching I have done. 4140, 1144, 1045 and chromed cylinder rod seem to be the top 4 of what I have found. But the chrome rod is expensive and Rc~62 for the chrome. And the 1045 doesnt seem to be as hard or have the yield strength of the 4140 or 1144

Pins in buckets and booms and the like are not a high strength application. They provide a connection and a pivot point, that's all. I have heard/read some horror storries about using a soft steel pin and them bending and are almost impossible to get out. THAT is what I DONT want. I frankly don't know if I've ever seen a pin in that application sheared, even when they were worn all to heck.

Just say'in

See above

Thanks for the replies so far. Keep them coming.

 

[Recoveryhill]

LD1:

Uh....I thought I specified which carbon steel and the three offered were 1018, 1144 and 12L14, no matter.

Press in bushings? Last I looked most of these receiver bosses are "welded" to the frames, including those on my Kubota LA463 loader. No matter part 2?

The diameter of a pin, in normal excavation and or agricultural service is sized by diameter according to the hydraulic capacity of the unit and is normally not furnished as a hardened pin, for reasons previously stated. How does a pin bend when it is supported between two "massive bosses" with minimal clearance, either side between the inside of the bosses and the moving part. You would need to move metal between the bosses and overcome the straightening forces of the bosses, literally extruding the pin, in order to bend. That would take hydraulic pressure, on steroids, but again, I concede your point, no matter part 3.

My response was only based on decades of repairing this stuff, probably 2,000 buckets, booms and fabricated cylinders and rods and "pins" but no matter, part 4.

Unless you're breaking concrete with a hydraulic jack hammer on the end of a boom, or operating a 1500 HP loader with a rock bucket, there is no need for hardened pins.

Just say'in

 

[LD1]

LD1:

Uh....I thought I specified which carbon steel and the three offered were 1018, 1144 and 12L14, no matter.

Press in bushings? Last I looked most of these receiver bosses are "welded" to the frames, including those on my Kubota LA463 loader. No matter part 2?

Recovery: I do appreciate your input and your opinions.

But for whatever reason, it seems like we are talking about different things.

Because you say you have worked on and repaired many booms, yet still question the bushings and hardned pins????

I ASSURE you they are pressed bushings and VERY hard. And I assure you they are HARDENED pins as well. This I have been able to determine by both googling and rockwelling of my own. And YES, the pin bosses are massive, but they still have a bushing to press in to protect them.

So....no offense meant to you, but I do have to ask your background??? Because with only a few posts.... Again, no offense, but what you are telling me is going against EVERYTHING I have managed to turn up googling.

I am questioning between 1144 and 4140, And you are telling me that just mearly cold roll 1018 would be fine and that you dont want a hard pin.

 

[tlbuser]

You may consider using 1018 or 1144 and finding a shop that could heat treat to your desired hardness.

 

[LD1]

You may consider using 1018 or 1144 and finding a shop that could heat treat to your desired hardness.

The 1144 already comes Rc24-Rc27. You think it would need additional hardening??

I am trying to do this all myself. And NOT have to have them heat-treated by a third party.

So I am trying to find suitable material that is hard and strong enough to endure backhoe use, while still machinable with carbide.

The hardest I can find at a reasonable price and still machinable is the pre-hardened 4140 @ C28-c35 (which is a pretty broad range).

So basically what I am down to asking now is:

IS the 1144 or 4140 hard/tough enough as-is, or is it too hard, or not hard enough yet????

The 4140 can only be hardend up to c40, while the 1144 is a tad softer, it can be hardened MUCH higher, as can the other carbon steels like 1018 and 1045 already mentioned.

IF the 4140 of 1144 isnt hard/tough enough and will require additional heat treatment, I dont want to spend the extra money and get it when I can buy a lower cost steel like the 1018 or 1045 and get it hardned. But that will cost more in the long run than if the 4140 or 1144 is aokay as-is.

 

[magicheater]

I find 1144 Stressproof sufficient for pins. Works easily but welds poorly, but with a pin no welding is required.