Hello, replacing a steel bushing on my case mini-sneaker trencher. The frame has been worn a little and the bushing is about 1/32 sloppy. The replacement bushing will slide in, while the 3 that are already on the machine are firmly attached probably driven in. I am sure from the vibration, the piece will deform shortly against the frame. I fear if I weld it to the frame, then it will just crack when the shaker head is turned on. Is this common? Any suggestions for a fix? Maybe some sort of epoxy then weld? Thanks for any suggestions.
Leon,coming from someone who has made a living out of fixing worn bores for 25 years I'll give two options.The right way to do it is to buld up the bore with weld and machine it to the right size. The second best way if you don't like welding is to oversize machine it for a sleeve which then carries the bearing.
Yair . . . Leon Phelps Good advise there from RayF and I would add that if you do decide to weld it in (if possible) assemble the unit and tack it with the pin in place. If you can chamfer the ends of the bore and get a good full penetration weld in there those sort of "fixes" can get you out of trouble and mostly nothing is lost. You have preserved the bore and the bush can be washed out later with the oxy and the job done properly when time and finances permit. Cheers.
Leon, you're right on all fronts. A loose bushing won't last 5 mins, it will pound out and you'll be replacing it again in a week. Any welding will crack in 5 mins, because the thin weld area is doing all the weight supporting, instead of the whole length of the bushing. Some epoxies MAY work, but I've rarely seen any that work effectively in this situation. A ceramic/metalized epoxy that expands when it sets, is what is needed - but all surfaces need to be extremely clean when its applied. There are some good epoxies around, but the problem with a bushing in a bore is trying to get an even spread of epoxy when you install the bushing. Driving the bushing in, tends to push the epoxy out. You need a bushing that has about 4 or 5 thou crush on it - like freeze it overnight, and then tap it in. Ray is right on the nail. Build up with weld and machine back (line bore), or make up a sleeve. You could try machining up an oversize bushing, but the fit of an OS bushing is highly dependent on an evenly-shaped bore. Rarely do worn bores have an even set of dimensions.