I found a small riding lawnmower differential on amazon for only $50, so going to try building a 6 leg version that will hopefully actually work when completed.
The Mk1 version was completed but a fundamental design flaw made it nonfunctional, Rogue Strandbeest Bike Build
Some of the changes for this version:
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Box or C construction on linkages - Instead of I beam construction (where parallelism and distance of two sides completly depends on the center portion being a precise size with perfectly perpendicular edges), will instead just box in the linkages with thinner plywood. This will improve tolerances and avoid extensive sanding / hand fitting I had to do previously
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Reduce scale - Everything will be scaled to 80% the size of previous version. Instead of the main triangles being two 1/2" thick plywood pieces glued together (which took significant amount of time to clamp each one) the main triangles will just be a single 3/4" piece of plywood, reducing construction time
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Fewer joints in metal frame - Metal frame will be simpler because only two arms instead of four will support each set of 3 legs (will depend on the rigiditly of 1/2" main axle for supporting middle leg). Use angle to connect the size to reduce chance of main part of frame warping during welding
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Simple feet - Instead of bolted on feet, will simply wrap the rubber stair tread around the bottom of the plywood
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Triangles are strong - Instead of the cantilever plywood arm design used previously that broke in multiple places, will stick with stronger triangular approach
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Differential - The main sprocket will be on a differential out of a riding lawnmower, this diff will have keyed straight couplings
Things that will be the same:
- CNC cut plywood for the legs, metal square tube for frame
- Delrin bushings and 1/2" axles everywhere
- Weld in crankshaft, the crankshaft will be constructed in the same way (bearings pressed into tube, then crankshaft sides welded onto rods going through bearings in place)
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