I built a Bolt Together Frame for my Maslow CNC.
But at step 11 and 12 in the instructions I decided to go a little different, and I’ve had zero problems with chains coming off sprockets, getting snagged, etc.
One part of Step 11 says:
Mark the middle of the top beam and install the two pulleys for the cable system just to either side of the center.
Yeah, I didn’t do that…
Instead I set up the pulleys so that one was to the top of the bar, and the other to the bottom. With both of them a long way past each other. With the idea that with the chain fully retracted (i.e. the sled sitting right up close to the motor) the stretchy cord on that side would have minimum slack and could still exert some tension on the chain.
A little like this:
Here’s the left side motor, with the pulley (and chain) going to the bottom of the top bar:
And here’s the right side motor, with everything going to the top. Depending on sled position the right side chain sometimes rests on the left side stretchy cord, but it never gets snagged in it.