One thing that I've never figured out in my time in vehicle events such as mousetrap vehicle and scrambler was (a) How do high skill competitors get threaded rods into ball bearings such that there is no play between the rod and the bearings, (b) it seems that an adjustable start height for the vehicle would be best but how did teams do that in the past? I may be wrong, but with heavy vehicles this year it seems that bearings are a must. Also, the only way to accurately cut the ramp that I've thought of is to laser cut. What is the recommended wheel durometer, I've heard banebot wheels are good but what durometer is best? Last year in MV I got the hubs to the axle by tightening with two wingnuts, so I was wondering how other teams did it. In a bit of a noob, so I'm sorry for a barrage of questions. : |
I'm definitely not the most qualified to answer your questions, but here is my take on things:
(a) I was thinking of getting bearings with an extended inner ring and fixing them in place on the axle with one nut on either side of the bearing. The extended inner ring would make sure the nuts don't interfere with the motion of the bearing
(b) For an adjustable launch height, you can design your launch mechanism to be bolted to the ramp surface or ramp sides. Then, make multiple holes along the surface or sides of the ramp so that the whole launch mechanism can be moved to the locations of the different holes.
As for ramp making, laser cutting would probably be by far the most accurate option, but most people don't have one available to them. To cut the sides, I believe you could use plywood, maybe 3/16 to 1/4 in thick and cut out the profile with some sort of saw. There are also options to support the ramp without the need for accurate cutting, such as vertical supports that are on either side and at multiple heights.
Yes, banebots wheels are good, and the best shore hardness will likely depend on the mass distribution of your vehicle. You want the wheels to have a soft enough hardness to provide sufficient traction, but not so soft that they cause extra friction and slow the vehicle down.