While I was building up some Athearn 20' container chassis kits, I decided to address the wheel slop issue. These kits have excellent running gear and nicely detailed wheels and tires, but when the axles are installed there is a lot of lateral movement of the axle within the running gear. On a previous model I solved the problem by adding four tiny washers to each axle. Two problems with that: first, I was out of washers and second, if you have to remove the wheels for any reason there goes a bunch of washers. A leftover bit of sprue from one of the Cosco kits was the solution. I drilled it out so the axle could be passed through and cut it to a short length to eliminate the slop. Some of the bits of sprue can be seen ready to install next to the chassis on the left.