Houndbot progresses

All four new shocks are now fitted! The tires are still deflated so they look a little wobbly. I ended up using a pillow mount with a 1/4 inch channel below it. The pillow is bolted to the channel from below and the channel is then bolted from the sides through the alloy beams. The glory here is that the pillows will never come off. If the bolts start to vibrate loose they will hit the beam and be stopped. They can not force the pillow mount up to get more room because of the bolts securing the 1/4 inch channel to the alloy beams coming in from the sides.

I'm not overly happy with the motor hub mount to wheel connection which will be one of the next points of update. Hopefully soon I will have access to a cnc with a high power spindle and can machine some alloy crossover parts for the wheel assembly. It has been great to use a dual vice drill and other basic power and hand tools to make alloy things so far. But the powerful CNC will open the door to much 2.5D stuff using cheapish sheet alloy.

But for now, the houndbot is on the move again. No longer to the wheels just extend outward under load. Though I don't know if I want to test the 40km/h top speed without updating some of the mountings and making some bushings first.

Houndbot suspension test fit

I now have a few crossover plates in the works to hold the upgraded suspension in place. See the front wheel of the robot on your right. The bottom side is held in place with a crossover to go from the beam to a 1/4 inch bearing mount. The high side uses one of the hub mount brackets which are a fairly thick alloy and four pretapped attachment blocks. To that I screw my newly minted alloy blocks which have a sequence of M8 sized holes in them. I was unsure of the final fit on the robot so made three holes to give me vertical variance to help set the suspension in the place that I want.

Notice that the high tensile M8 bolt attached to the top suspension is at a slight angle. In the end the top of the suspension will be between the two new alloy plates. But to do that I need to trim some waste from the plates, but to do that I needed to test mount to see where and what needs to be trimmed. I now have an idea of what to trim for a final test mount ☺.

Below is a close up view of the coil over showing the good clearance from the tire and wheel assembly and the black markings on the top plate giving an idea of the material that I will be removing so that the top tension nut on the suspension clears the plate.

 The mounting hole in the suspension is 8mm diameter. The bearing blocks are for 1/4 inch (~6.35mm) diameters. For test mounting I got some 1/4 inch threaded rod and hacked off about what was needed to get clear of both ends of the assembly. M8 nylock nuts on both sides provide a good first mounting for testing. The crossover plate that I made is secured to the beam by two bolts. At the moment the bearing block is held to the crossover by JB Weld only, I will likely use that to hold the piece and drill through both chunks of ally and bolt them together too. It's somewhat interesting how well these sorts of JB and threaded rod assemblies seem to work though. But a fracture in the adhesive at 20km/h when landing from a jump without a bolt fallback is asking for trouble.

The top mount is shown below. I originally had the shock around the other way, to give maximum clearance at the bottom so the tire didn't touch the shock. But with the bottom mount out this far I flipped the shock to give maximum clearance to the top mounting plates instead.

So now all I need is to cut down the top plates, drill bolt holes for the bearing to crossover plate at the bottom, sand the new bits smooth, and maybe I'll end up using the threaded rod at the bottom with some JB to soak up the difference from 1/4 inch to M8.

Oh, and another order to get the last handful of parts needed for the mounting.