[Joe G.]

I would tend to agree with Tom, it's a bit late in the game to be getting this kind of thing squared away. However, if you really want to pursue a custom sheet metal chassis, here are some tips:

• Unique part count is the name of the game when it comes to sheet metal. The more you can use duplicate parts, the less it costs to produce, because programming of bends is a hefty portion of the labor involved. Do what you can to reduce the number of unique parts in your assembly. Why aren't the front and back rails identical? Same with the pieces across the bottom? Any chance that the drive rails themselves could be identical? These are the kinds of questions you need to ask. I have designed sheet metal chassis' that gave me everything I wanted with as few as two unique parts. The andymark C-Base is an example of a sheet metal chassis with one unique part.
• Similarly, the more you can standardize thicknesses, the better.
• One part that looks of particular concern is the main wheel module. Narrow, deep C-channels like that are very hard to bend. In general, you want a leg length shorter than the base width to ensure that no special tooling will be required.
• Work with the sheet metal supplier, don't just send them drawings and demand exactly what's pictured. For example, every shop will have a bend radius that they prefer to work with for a given thickness of metal, which you should design into each of your parts. There are many little ways that they'll be able to show you that can reduce costs.