This has to be one of the cheapest and easiest ways to create gears for medium-sized weekend projects. In a pinch, cut some MDF about the same size as the gear you want to make and then glue a piece of automotive timing belt around the circumference. The resulting gears end up matching well with other similar gears and you get the added bonus of being able to use a timing belt. How cool is that? [via Dug North]
18 thoughts on “Easy to Make MDF and Timing Belt Gears”
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Cool, I just threw one out. I couldn’t imagine putting it back on my car and couldn’t think of a use for it. Now I need to go and dig it back out of the trash.
I’ve seen a similar technique that involves spraying release on the timing belt, smearing epoxy on the circle, and then pressing the belt to mold the teeth. This is relatively effective; I know of people putting somewhat high power through the gear assembly (because this is done on the gear with the lower load). I’ve only seen it done with metals, and there might be a problem with seepage into the MDF.
Looks interesting; how much trouble is it to get the circumference just right to get an integral number of teeth? And, can you use these gears to drive a timing belt?
yeh, “about the same size as the gear you want” isn’t going to cut it, need to be pretty accurate to get an integral number of teeth.
there are several types of timing belts some will mesh with it self, but not all
I don’t think that kind of accuracy is actually necessary. Where the ends meet, you would obviously like to have one full tooth next to one full dip, but I believe you could get away with having a dip bigger than a tooth. You couldn’t get away with a dip smaller than a tooth, obviously, because then your gear would jam. As long as the dip is small enough that the gear is rotated far enough for the next tooth to engage, you should be fine (small enough still being larger than one tooth).
I’m sure there’s a nice formula for finding acceptable tooth/dip ratios and tolerances in The Machinist’s Handbook, but I don’t know it.
I know, on motorcycle chain drives, if a link is stretched (same as having a tooth with a bigger gap) it will quickly chew up the rest of the links and teeth. Because it moves back and forth on them.
“And, can you use these gears to drive a timing belt?”
I would assume so, but probably not with the exact same type unless the gears were fairly big. Your belt would have to have less teeth per inch. As the belt goes around the outside the teeth get closer together. The teeth on the gears are just the opposite, they get father apart with the smaller diameter.
I’m thinking wheels for a robot.
How can I buy that belt?