Page BottomA few years ago, i salvaged some 150 feet of bicycle chain in 10ft to 20 ft lengths, yet have a narrow range of sprockets to deal with the chain. I have sprockets off of ~10 bikes, but no very small sprockets (except some welded to shafts), and none in between bike crank and bike rear wheel sprockets in size.
So now to make the sprockets i need.
Some of the chain. Yes, it's old, dirty, some has a little rust on it, but i can pick and choose which i use for what, and the task at hand is the synchronising the ends of the bridge beams on the driveway overhead crane. It won't be turning fast, or with much stress. Or that often, i suspect. And it will get dew on it nearly every morning. Well, maybe it could use an oiler.
What to start with, 2x2 inch pieces of 1.110 thich plate. This is also recycled metal. I picked it up because it looked suspiciously like front panel material for 19 inch rack equipment. I am not going to use it all on sprockets!
I deburr it, drill a 1/2 inch hole in the center, ream and deburr to fit tight on the axle this sprocket was welded to. I am essentially copying this old used sprocket.
I dinged the top plate with an appropriate center punch and then drilled pilot holes with the drill press:
Made the holes bigger and then compared them to the original i was copying:
After cutting off the corners of the square pieces, i "chuck" the two plates onto a 1/2 inch bolt, and then it's tricks with the drill press again:
Deburring and shaping the teeth by hand. I did it in the drill press because it was already holding the almost-sprockets exactly where i wanted them. I tapered them by grinding a little at a time, holding and turning the drill press chuck with a gloved hand. The taper is a line tangent to where i imagine the edge of the 1/2 inch shaft is.
And the finished product with chain on it, good enough to work for what i want. Naturally, the more expensive the toys used to make something, the better it turns out, especially if the toys are those designed to do this sort of work. But this is quite adequate. Shown with the amount of wrap they'll have when placed on the bridge crane.
Three hours, start to finish, including taking these pics and then making this webpage!
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