Some time ago I mentioned that The PTO side of the crankshaft can be turned and keywayed without removeing the crank from the engine. I had done it in the past but I got the idea that no one believed me. So here we go with pictures.
I was given a dirty but low hours 3 HP Briggs the has a 5/8" threaded shaft. Also the body of the shaft was .005 over 5/8". There of course was no keyway. Impossible to mount a Comet clutch. The shroud was removed so the starter side so the crank could be chucked up in a 3 jaw. See picture. A hunk of wood was screwed to the base of the engine block so that it would not spin with the crank. The spark plug was removed. The oil in the engine and the gas in the tank were not removed. First the end of the crank was drilled and tapped for a 5/16 bolt like normal shafts. Then the tailstock with a live center were used to support the shaft and then it was turned to .001 under 5/8". After that the engine was put in the mill and lined up correctly with a dial indicator and a 3/16 keyway milled. Note the pair of Vice-Grips that is used to keep the shaft from turning while cutting the keyway. The clutch fit just fine. It is too bad that so many good engines have funny shafts and to make them right it takes a lathe and a mill. But sometimes it is possible to at least avoid having to completely disassemble the engine.
I was given a dirty but low hours 3 HP Briggs the has a 5/8" threaded shaft. Also the body of the shaft was .005 over 5/8". There of course was no keyway. Impossible to mount a Comet clutch. The shroud was removed so the starter side so the crank could be chucked up in a 3 jaw. See picture. A hunk of wood was screwed to the base of the engine block so that it would not spin with the crank. The spark plug was removed. The oil in the engine and the gas in the tank were not removed. First the end of the crank was drilled and tapped for a 5/16 bolt like normal shafts. Then the tailstock with a live center were used to support the shaft and then it was turned to .001 under 5/8". After that the engine was put in the mill and lined up correctly with a dial indicator and a 3/16 keyway milled. Note the pair of Vice-Grips that is used to keep the shaft from turning while cutting the keyway. The clutch fit just fine. It is too bad that so many good engines have funny shafts and to make them right it takes a lathe and a mill. But sometimes it is possible to at least avoid having to completely disassemble the engine.