[Nathan Streeter]

Looks very clean - great job doing some educational, practical off-season work... best earmark of an improving team, in my opinion!

I second those who have mentioned teams using wood drivebases... it can be done very well and can be significantly easier to fabricate. I recall 173 - at least on their 2007 robot - used a many-ply (9 or 11?) birch plywood of about 3/8".

I don't have any experience with wood drivebases personally; however, our team (especially in it's early days) tended make things way too beefy and heavy. I know Oak is surprisingly dense, so I recommend intelligently experimenting some with using thinner/smaller parts in lower-load areas (it's easy to use a heavier member than needed just because you use it elsewhere... we've done this with 80-20, when many components could be 1x1x1/16 box alum, which is half as heavy). Speed-holing can also provide some weight savings... although I have also seen teams over-speed-hole a critical points. All that to say, "Be careful of surprisingly heavy drivebases... a 6WD doesn't need to weigh >50 pounds without electronics."

Also, if you're looking to save weight, switching to #25 chains or timing belts can be a good way to do it. The larger your sprockets are compared to your wheel diameter, the less tension they're subject to... A small change I recommend with little/no cost is to make the longer chain runs between the center wheels and the end wheels #25 chain instead. With a >3.5" sprocket, I would be surprised to see a failure on that chain run, but even then you'd still have 4 or 5 driven wheels.

It looks like you're using a 3/8" bolt for your axle... which I like using for dead axles... although be careful not to over-tighten them! I would recommend you make sure it's a Grade 8 bolt, though. From our team's experience, a standard (Grade 5) bolt is unlikely to hold up in competition.

I would strongly recommend implementing now the stiffness modifications you expect to make... Drive Bases - particularly 4, 6, and 8WD ones - take a surprising amount of internal load. A particularly important degree of stiffness is bending along the diagonals (when viewed from above). Drive Bases with insufficient stiffness can make a 6WD base with plenty of "center drop" hop. It's important to have a sufficiently strong drive base if you're going to be testing and comparing different drive trains, so you can get useful experience with each.

Best of luck this year!