Inertia Vehicle

You will need the ability to tap M4 – 0.7 holes. All holes requiring close fit are modeled about 0,1mm undersized, requiring post-printing drilling out to size. This technique is especially beneficial for holes where the axis of the hole is not in the Z direction. The tapping requires good operator technique. Without it the parts may crack during tapping. Tap drill size of either .125 or .128 inch is correct for M4-0,7 thread. While the parts requiring tapping can be printed in PLA use of a stronger material such as PETG is recommended.

The frame and three gears might well be printed at a higher than normal infill – say 40%. Obviously print the cover upside down. You might need to create some fixturing to space the bearings so that the flywheel assembly drops neatly into the pair of provided pockets. Ideally both inner and outer bearing races should be immobile after final assembly. Apply only light finger tightening of the four cone point set screws to avoid breaking the bearing recess ears.

List of required hd’we:

* M3 x 27 O-ring – qty 8

* M3 x 100 rod – aluminum or stainless steel – qty 2

* M2.5 x 25 rod – aluminum or stainless steel – qty1

* M5 x 45 close tolerance rod in stainless steel – qty 1

* 5 x 9 x 3 ceramic, non-lubed fishing reel bearing – qty 2

*4-20 x.25 self-threading, pan head screw – qty 4

* M4 x 6 cone point set screw – qty 4

*M4 x 3 cup point set screw – qty 6 or 11 depending on redundancy or no redundancy

* Washer – STEEL or ST STEEL (not aluminum) .680” ID x 2.012” OD x .116” thk (or something close that fits the well)