suspension.html

Suspension

This is the body after primer. I used 3/4" steel tube for the bogie suspension, with 2x4 bars inside the shell. My source for the tube was Lowes, which didn't carry lengths over 3 feet. I needed a bit longer than this, so I cut the tube in half and used the 2x4's to bear the load. Note the thin plywood construction with 1 1/4" square wood chines at the panel joints. This construction technique is described in the original plans.

This view shows the suspension. On each side there are three bogies, each consisting of 4 wheels, a spring, and a wood laminate. The laminate was made out of 2x4 and 1/2" plywood.

The bogie halves are hinged on the 3/4 " tube bolted to the underside. At the tips of the laminates 1/2" shaft was installed and fitted with 6" lawn mower wheels.

Chevy 350 valve springs were fitted between the bogie halves to suspend the tank. I chucked the 1/2" shaft in a drill press and used a hack-saw blade to cut a notch for the 'e' clips which secure the wheels. Flat washers on both sides of the wheels were fitted to keep the wheels from rubbing against the laminates. The bogie assemblies are attached to the tubing with washers and bolts.

Here's a side view after the track is installed. Starting to look like a tank! Note the idlers that hold up the upper track. Without them it was too difficult to get the track from hitting the top of the bogies. I was too cheap to buy wheels so I make them out of wood disks and epoxied aluminum strips around their circumference.

Wood blocks on the track links fit between the wheels to keep the track where it belongs. At the right of the photo you can get a peek at the drive wheel hub with bolts holding the gears.

The idler is an assembly of two larger lawn mower wheels and a steel frame that allows the track to be tensioned. The frame is make from 1 1/4" 16 gauge square tube and 1" angle iron. The whole thing is attached to the body with two bolts that fit in the slot between the angle iron.

The Steel tubing that the tank is suspended on has started to bend from the weight, so I had to pull it out and replace it with solid steel bar. The rear set was bending enough to easily see, and the other two axles, upon closer examination, were showing distortion as well.

This is the removed assembly. The design is complex because at the time I had no convenient source of long steel tube, so I used a 3' length, cut in half, mounted as two pieces.

I replaced all three axle assemblies.

Having found longer stock, the design is much simpler. I used short lengths of 1 1/4" angle and 1/4" bolts to mount the axles, which are 38 1/4" long.