I have a small excavator that needs pin and bushing replacement at the end of the stick. The bore in the stick is shot as well. I have the ability to machine out the bore, but lack the technology (money actually) to be able to weld up the bore first, so i am going to machine my own bushings with oversize O.D.. Using a steel alloy means a trip to the heat treat shop, and a minimum charge. I am also not familiar enough with heat treating to know what if any dimensional changes to expect. I was thinking, instead, of using 954 aluminum bronze since the strength is high and it is readily available in cored round stock. I have made bushings from this material before with success, but never for an application this demanding. Any opinions on how this might work out long term? Is there a better alloy for this application? This machine is only a 35 size, but it frequently has a breaker or compactor mounted. Thanks. Brian.
I don't think bronze will last in that application. I have made oversize bearings for small loaders that have lasted 7000 hours +. I have machined them out of 4140 and heated and quenched in oil. They have to be machined with a ceramic tip after the heat treatment as they go out of shape. I'm not sure how they would stand up to a breaker. The other way would be to machine them oversize out of EN14 and get them carburised at a heat treatment shop then final machine them. They would be as good as an off the shelf bearing.
Hi there, Volvo use aluminum bronze in there loaders and it lasts very well! I have also bored out bosses over sized and used Nylon of bushes! It lasts really well and is alot less costly then bronze!
RayF, Thanks for the info. I hadn't really considered using bronze in this application until I read the bushing removal thread here recently, where the topic of discussion was removing the bronze stick end bushings on a Hitachi 120 excavator. That got me to thinking... Looking on the web, the newer Hitachi machines seem to have something they call an HN bushing which looks like old fashioned oilite bronze. Not sure if this is just a coating on a hardened steel bushing or solid material. Anyway, that got me to wondering if aluminum bronze, which I think is on the high end for strength of all the bronze alloys, might be suitable. Just pondering whether there is a simpler way that avoids heat treat and some tough machining afterwards. Brian
It would not cost much to spin up a couple of Ally Bronze bearings and try them. Cat use them in scraper cushion hitches and they are OK in that application. I reckon the secret would be keeping the dirt out of them.A good lip seal and a O ring around the outside of the boss and a operater I know also wraps rag on top of that. I never bore his buckets.
Good ideas. Thanks.
That's really interesting. I could see them working on a mini ex. Even if they didn't last as long they'd be a snap to replace. Do you think they would work for boom cylinder bushings?
Do some homework on Industrial plastics Rob. A lot of them won't be strong enough and also note they would have to have a lot more interferance/crush than a steel bearing. Also plastics can be expensive. I bought a bit of Vescanite this week.35mm dia and hollow and 200mm long. It was over 50 bucks.
I work for National Bronze Mfg we specializes in manufacturing bronze bushings. We manufacture a large amount of bushings for similar equipment. From my experience I can tell you that C95400 Aluminum Bronze Alloy and C86300 Manganese Bronze Alloy are used often. You can take a look at our website, there is a lot of technical information under the resources section. www.nationalbronze.com Aluminum Bronze Manganese Bronze Resources