The Modulox has worked out very well. everything is Aluminum except the bearings and output shaft. We have discovered that chassis construction is very important to the success of the Mecanum drive. Both frames we have built were very rigid, square and durable. All of our cut dimensions are +- .010 and all of our bends are +-.030. All rivet locations were pre drilled and require very little modification for assembly. There are 125 3/16 blind rivets holding 9 parts together. With the CIMS the chassis weighs in at 43 lbs.