[Dick Linn]

A couple of times, we've mounted each drill motor and small sprocket shaft on an aluminum plate. This plate has slotted holes and can be moved in relation to the drive wheel to tension the chain when necessary. We can also use washers between the plate and the chassis rails to get additional range (yeah, the slots weren't long enough...). Keep the chains lubed, snug and aligned and you'll have less chance of breaking a chain when it tries to climb up and over the sprocket teeth. Also avoid tiny sprockets.