|Close-up of the sub-chassis|
Next I started on the main side frames. I built these from 0.09 inch square brass tube. Again, I made a jig to help hold the small brass pieces while I soldered them. The frame dimensions are not too critical as long as they allow the sub-chassis to rotate about the pivot axle. With the jig they came out pretty close to identical, or at least close enough.
|Jig to keep axles parallel|
|Frame jig showing top beam with bend.|
With both frame sides built, I cut two brass 0.5 by 0.8 by 1/32 inch plates and two 0.09 by 0.09 by 0.8 inch square tubes to act as transverse members. Again, I soldered them together and used my disk sander to square the ends and make them all the same length. The photo below shows the completed sub-chassis and the main frame.
I have to figure out a way to cover the gaps at the bottom of the hornblocks. I'll probably add small keeper plates that will be soldered on or maybe screwed in if I decide they need to be removable. I don't think they do, so solder may be OK.
|The sub-chassis installed in the main frame. |
Next I fitted the gear box and motor to the front axle. This took a little bit of fiddling to make it work.
|Motor and gear box on the front axle. |
Here is a short video showing the chassis rolling on Potomac Creek bridge. The results have been encouraging so far.