cylinder pin material

[Randy88]

Seems the question of the day is..........what material do most make cylinder pins out of, turns out we broke the lift cylinder/boom pin on one of my excavators, went to order a new one, was told they quit making it two years before my machine was built?? Well anyhow, you guys know how its working out, if I ever intend to use this machine, we'll have to make a new pin myself. Though I'd ask locally first, turns out there must be a lot of options, because everyone had a different recommendation, but none had actually made a pin for an excavator before.

Now with the economy and parts the way they are, that whole put it back together again and send it to auction might not happen just yet, we might have to use this machine for a while first, so I thought maybe ask those who've made pins and used them for a while, what do you make them out of, what grade of shafting, do you heat treat it after you machine it, not heat treat it at all, what??

So far I've been told stress proof, 4140 some say to heat treat it, some not just use it as is, 4130, S7 and a few I can't remember now, but it didn't matter because they couldn't get me that anyhow from any steel supplier.

We had the broken shaft tested, think it tested at 5658 for hardness if that means anything to anyone. Not sure what it means but the shaft itself was soft enough to file with a hand file really easy, which is thought was a little odd for a shaft used where its at. As far as I know, the shaft is original to the machine, at least for the 20 plus years I've owned it anyhow.

We've thought about going a size larger, but turns out we can't get them either, so boring out the old rods and boom and putting in a larger one isn't really an option now either, not sure how hard the bore in the boom is either to bore out, anyone done that before??

 

[Tyler d4c]

Chrome cylinder rod out of a junk cylinder of the correct size.

 

[John C.]

What I did one time on an American crane converted to hydraulic for use in a scrap yard was get a bushing out of the boss the pin goes through and have it tested for hardness and type of material. Get as close to the same material and harness as possible.

 

[56wrench]

The old one was likely induction hardened to about 1/8” depth. Like an m&m- hard on the outside, soft in the middle If it was through-hardened, it may be too brittle.

 

[Tinkerer]

Could the bushings be modified to accept an OEM pin that is available ?

 

[Randy88]

As for going a size larger in diameter, those pins we can't get either, most are too short in length. If I go larger in diameter, I'll have to make that pin as well, thats the same thing everyone I've talked to has told me.

All the places I've talked to so far are telling me that bucket pins are much softer than the cylinder pins that mount to the boom, as some say, that's the break away point to save the boom and boom cylinders. Not sure I haven't tested those pins yet, not really sure it matters, they'll all shorter anyhow.

I have yet to measure the bore of the bushing with a much more precise measuring device, but on first inspection, it doesn't measure much wear, so I'd rather not cut it out to either have it tested or replaced just yet. One would think the bushings are made of harder material than the pins, seeing how upon inspection the pin was worn and not the bore of the bushing. We've discussed line boring it larger to fit a larger diameter pin we'd make to account for the maybe weaker material we might end up using to make the pin from, but as of today, finding the material at all to even make the pin is somewhat tough it seems, called a half dozen steel suppliers and they have literally nothing in stock or on hand, many didn't think they could even get me much of anything so to speak. I still have a few left to call or am waiting to hear from them. This might get down to what material I can get, not what material is ideal for the application at the rate this is progressing.

When I asked about using a chrome cylinder shaft, I was told it might work for a bucket pin but not anywhere near strong enough for a cylinder pin, but no I haven't gotten down to actually getting an answer on what rockwell hardness those are, I'm waiting for actual people to call me back with numbers yet.

At first getting a replacement pin was hard, now trying to find anything to make a new pin out is about equally tough it seems, is everything out of stock or on backorder in the whole country? I understand we'll have to turn it down to size and not get an exact fit shaft since it mm and not standard inch size, but right today, its not looking good we even get much standard sized shafting at the rate this is going.

 

[Tyler d4c]

What size is it by chance

 

[Tinkerer]

Post the pin measurements and you will have a lot of HEF'ers looking for you.
Most likely somewhere there will be one sitting on a shelf collecting dust.

 

[Randy88]

65mm x roughly 28 inches long. I have to remove both cylinders first to get both portions of the pin out, then compare and measure for exact length and hole size and location. Then remove the cracked pin [right now both are in temporarily holding the cylinder in place so I could move the machine into the shop. I just measured the broken portion for diameter and used the whole about this long method to get the rough length so far. More caliper work and we'll have it exact. The second pin I haven't even measured yet, nor checked any of the rest yet still in place.

After more phone calls than I care to remember, I have someone who thinks they can get the shafting to make the pin for me, which is a huge step forward compared to anyone else that says upfront, don't have and can't get the raw materials to even think about doing the pin or pins. I need to get them off and take them in tomorrow, he wanted to do his own testing on them to be sure he had the same material as the originals. The best part is, he's only a few hours drive one way and there is hope I guess and maybe I won't have to do any machining myself, time will tell.

I guess with time things change, first its the ability to buy toilet paper, next was waiting over six months to get my washing machine parts and get that working, now its to find someone who can get the raw material hard enough to even make a pin, LOL wonder whats next?? Not exactly sure this is what I was thinking progress was supposed look like even a few years ago, but maybe my expectations were too high back then, to drive to the dealer and actually buy OEM parts that were in stock or could be ordered, who would have ever thought that was an unrealistic expectation..........

 

[crane operator]

I've got two good machine shops near me, if you get really stuck, let me know what it is and I bet one of them near me can make it.

 

[joe--h]

I guess with time things change, first its the ability to buy toilet paper,
And did you ever think toilet paper would be over $1 a roll? 30 pack of Charmin $31+, and that's 2 weeks ago.
But more ammo, Joe H

 

[1466IH]

Most bucket pins I come across are induction hardened chrome rod. The same stuff the cylinder rod is made from. Have a company I buy all my rod and barrel tube from and will sell it to you any length you want. Can look the place up tomorrow when I get to shop

 

[Randy88]

I took my shafts in and they measured them up, said the new ones should be done mid next week, it took him a while to locate some more material since he was out of that size and it was a rather small size compared to what he usually deals with. Not sure where he found it from but none of the steel suppliers I've dealt with had a clue where any was, same for all the actual machine shops, but at this point, I don't care as long as I can get it back together and going again for now. This whole ordeal has drawn out for over two months now and tied up a portion of my shop.

The more info and places to locate anything from in today's age is a valuable thing, and might well be what keeps a lot of equipment going.

 

[fast_st]

I've used scrap cylinder rod sections before, My local shop will sell me a 2' length of 50mm for $30, The softest part gets the wear, so a slightly softer pin will help the bushings last a bit and replacing a pin can be somewhat easier.

 

[Tinkerer]

Maybe have two of them made so you don't have to go through this ordeal again.

 

[Randy88]

I've owned this machine for over 20 years now and its the very first pin I've ever broken not sure it will live long enough to worry about a second pin, even if I did get two made, and broke the first, doubt I'd ever find the second one by then anyhow or ever remember where it got put so nobody would forget where it was at when needed.

 

[Entropy1]

https://www.crconline.com/catsearch/174/induction-hardedned/

Induction hardened chrome rod is hard to beat for DIY replacement pin-joints. The center steel is ductile (aka tough for impact-load resistance), and the outside is as hard as a drill bit (for extreme wear resistance). The chrome finish (72 HRC) prevents scratches & rust. The only downside is that if you require grease holes. Drilling down the length of the rod for grease holes isn't a big deal, however forget about drilling through the induction hardened portion of the rod. You'll need to use abrasive bits to grind away a grease hole through the induction hardened portion. Also don't try machining the outside of the rod (the outside of the rod is almost as hard as lathe tooling inserts). Welding isn't advised either. Medium/high carbon steel requires appreciable preheat to properly weld without cracking, and even with proper heat controls, welding will significantly temper the induction hardening of 1045, and also further temper the through-hardening of 4140. The company CRC (linked above) has an excellent selection of induction hardened chrome rod, in both standard and metric sizes. Not cheap, but not expensive either. When you need it, they've got it - and the rod is excellent quality. Note: hardened spring-steel split-bushings work well with this rod for pin joints. And the one-piece OEM hardened bushings are also very compatible. Again, it's best to not to disturb the pin (aka no drilling of grease holes). Instead, modify the pin-joint bushings to accept grease via the bushings.

Additional notes: for extreme loads on pin joints (excavator pins, dozer pins, loader pins, etc) the ideal surface-hardness for both pins & bushings is about 55 HRC (50 to 60 HRC is acceptable). Extreme pressure grease is your friend. Induction-hardening of pins is easy to hit desired hardness, while also maintaining adequate toughness in the core for impact loading. Machinery bushings however are normally through-hardened & tempered. They can be as low as 45 HRC (still very strong, but they will wear faster than the pin). The problem with too high of hardness on bushings is that they'll shatter during impact loads (a product of through-hardening vs case hardening). As with everything in life, pin-joints are a balancing act. Induction-hardened chrome rod will meet (or exceed) any OEM pin material.

 

[fast_st]

My local hydraulic cylinder dealer sells new and used chrome rod pieces at a very reasonable price. I bought 2 2' pieces of 50mm for $20 each

 

[nowing75]

https://www.crconline.com/catsearch/174/induction-hardedned/

Induction hardened chrome rod is hard to beat for DIY replacement pin-joints. The center steel is ductile (aka tough for impact-load resistance), and the outside is as hard as a drill bit (for extreme wear resistance). The chrome finish (72 HRC) prevents scratches & rust. The only downside is that if you require grease holes. Drilling down the length of the rod for grease holes isn't a big deal, however forget about drilling through the induction hardened portion of the rod. You'll need to use abrasive bits to grind away a grease hole through the induction hardened portion. Also don't try machining the outside of the rod (the outside of the rod is almost as hard as lathe tooling inserts). Welding isn't advised either. Medium/high carbon steel requires appreciable preheat to properly weld without cracking, and even with proper heat controls, welding will significantly temper the induction hardening of 1045, and also further temper the through-hardening of 4140. The company CRC (linked above) has an excellent selection of induction hardened chrome rod, in both standard and metric sizes. Not cheap, but not expensive either. When you need it, they've got it - and the rod is excellent quality. Note: hardened spring-steel split-bushings work well with this rod for pin joints. And the one-piece OEM hardened bushings are also very compatible. Again, it's best to not to disturb the pin (aka no drilling of grease holes). Instead, modify the pin-joint bushings to accept grease via the bushings.

Additional notes: for extreme loads on pin joints (excavator pins, dozer pins, loader pins, etc) the ideal surface-hardness for both pins & bushings is about 55 HRC (50 to 60 HRC is acceptable). Extreme pressure grease is your friend. Induction-hardening of pins is easy to hit desired hardness, while also maintaining adequate toughness in the core for impact loading. Machinery bushings however are normally through-hardened & tempered. They can be as low as 45 HRC (still very strong, but they will wear faster than the pin). The problem with too high of hardness on bushings is that they'll shatter during impact loads (a product of through-hardening vs case hardening). As with everything in life, pin-joints are a balancing act. Induction-hardened chrome rod will meet (or exceed) any OEM pin material.

It can be machined if you use ceramic inserts. Look up cutting edge engineering on you tube. He just made some pins a few weeks ago.