Just some basic questions about mounting gears on shafts. I'm trying to stay with readily available stuff and nothing exotic. So for the situation where both the shaft and gear rotate there seems to be these options:
1. Pressure fit (not sure how you would go about matching shaft and gear, doesn't sound like a 6mm bore gear would be a pressure fit on a 6mm shaft).
2. Gear with a set screw on a round shaft (seems like this would slip under high load?)
3. Gear with a round bore and set screw on a keyed shaft, like a "D" cut. (does this work?).
4. Gear with a keyed bore and set screw on a keyed shaft (seems like it would be the ultimate but how do you match them up from different suppliers?)
Then there is the option of the gear spinning freely on a fixed shaft(axle). But how do you match these up? It is the inverse problem of #1 above. Does a 6mm bore gear spin freely on a 6mm shaft? How much friction do you get with this setup?
Then there is the issue of 1/4" vs. 6mm. Some sites seem to use this measurement interchangeably. I could see maybe pressure fitting a 6mm bore gear on a 1/4" shaft. But the other way around wouldn't the gear be too loose?
In specific I like the selection at this site:http://www.robotobjects.com/scripts/prodList.asp?idCategory=39
But I'm having trouble finding a nice selection of wheels and shafts that aren't 6mm.