Counter balance

As with quite a few of these mini-projects for the conversion, a big part of the challenge is figuring out a temporary solution for problems that require the machine itself to resolve permanently. The counterweight system is a case in point. I didn't have anything conveniently shaped and heavy enough to offset the mass of the head. So instead, I put together a Rube Goldbergesque arrangement of improvised pulleys (shackles with bits of tube for rollers) and some more plywood scraps to make a block and tackle. This part worked fine, generating more than enough resistance with a single piece of 1" steel plate.

The idler sprockets directly above the Z-slide proved more troublesome. There is no space to put an axle all the way through as the support posts for the stepper mount interfere. Consequently, the sprockets have to be bolted onto the mounting plates creating a cantilever condition which generates enough torque to significantly bend the 1/2" birch plywood. Even with an F-clamp installed, the bending was enough to make the chain start to misfeed occasionally!

Still, it works well enough to actually cut parts using all three axes for the first time. 

The first parts cut are of course the necessaries for the permanent version of the counter-balance system.