Regarding the driveshaft support bearing – typically the section of the lower unit that supports the lower end of the driveshaft was not bushed from the factory. Usually the casting is bored out to finished size. When the driveshaft bore gets worn out, it is almost always a nuisance to repair if you don’t have a jig for it, or a way to hold it in your lathe. My usual method to fix this part is to clamp the gear housing to an angle plate in a milling machine and bore it out. The skeg makes it a pain in the butt to get it lined up and indicated, but with enough parallels and clamps in the tool kit, I manage to get thru it without burning up the air around me with words that aren’t fit for listening to. This is one area where I will admit to having bowed to the Spirit Of The Unholy Shortcut, and machined a stepped shaft to work around a worn out bearing bore after I reamed the hole out to the point that it was more or less round again. That was in the days when I either had no machining equipment to work with, or lacked the prerequisite level of knowledge to know how to do it better. But it is a shortcut that can get you by, especially if you can’t hold the work in a lathe chuck or fixture, and a milling machine isn’t available.
Regarding the choice of bearing – If its off the shelf, its likely an oilite bronze bushing, or similar material. They will do fine in the short term, and if you’re only planning on getting a few hours of fun out of the motor before it retires, you will get your moneys worth out of them. Plus, you can always press them out later and replace with SAE 660 bronze if you want.
Oil groove – your method would work. My neanderthal method involves first cutting (or broaching, to put it more accurately) a straight groove in the bushing with a boring bar. Obviously you don’t want to go all the way through the bushing, I aim for about making the groove 80% of the length of the bushing. When I get the groove to the depth I want, I just put a bit more tension on the boring bar and put the lathe in back gears at the lowest RPM, then rapidly withdraw the tool as soon as the lathe is turned on. I get a spiral cut groove that is as deep as the one I just broached. The sound the tool makes as your withdraw it from the work will cause all the other tools you own want to run for the hills lest they be subjected to similar abuse…. I did say it was a brutal way to do it, but it works. I’d like to build an apparatus that uses arms attached to the chuck to move the carriage back and forth in such a manner that you can make those nice figure 8 oiling grooves, but I haven’t gotten around to that yet.
Hope this helps.
Best,
PM T2
He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...
