I should have made another thread about the gearboxes... but okay...
I am just wondering if your motor mounts are strong enough keep the drill motor from spinning out because of torque in the gearbox... i am saying that since i have experienced it... we had something like a mexican hat which held the drill motor in place and then bolted that into the gearbox plate...
The design looks great so far... whoever drew it... put some quality time in it... good luck...
