Some interesting stuff going on there, David! The thought occurred to me that the wheeled drives with short tooth belts are probably more precise over time, versus typical CNC (and my machine) with long belts and their stretching over time. Your thoughts?
Belt stretch is never a concern for me as my machines rarely stay in the same configuration for very long... and I'm certainly never going to wear one out from "over-use"...
Concerning the closed-loop belts, I had started playing with @geodave's Rolling Plotter some months ago. Got to the point of ordering some 444 mm closed-loop belts and then pushed everything into a corner while waiting on their delivery. On a much slower boat than normal… my 444mm belts were finally deemed “LOST [at sea]” by the shipper. With the pandemic and shipping disruptions, I decided against reordering anything right now and had pretty much given up on having a rolling plotter in my future anytime soon. Then a few days ago, mysteriously, a small package arrived in the mailbox… looking fine and normal, just LATE! Getting pretty bored just playing around with my laser, I was starting to look for something new to play with... and then this arrived, just in time!
So I started playing with Dave's original endplates, which I had already printed… and started modding them to take advantage of parts in my stash. With zillions of 608 bearings on hand, I elongated one idler bearing slot to allow a single 608 idler to replace the two-bearing idler setup of the original endplate.
With the belt routing looking reasonable for now, I then took a look at the extrusion to endplate connection. I have a couple of 1000mm 2040 extrusions that I’m reluctant to cut to length until I know more about how I might use this thing… and decided I’d really like to try setting it to the same width as my FoamRipper gantry and work surface. So I reworked the extrusion “shelf” to allow the extrusions to “pass through”, for width adjustment and even endplate reversal (wheels inside or outside) if necessary.
The endplate extrusion mods and the near-original (the idler slot had already been elongated) for fixed-length extrusions...
Having now printed a second endplate to match, I'm to the point of getting this thing wired up and moving. I’m hoping to honor Dave’s mechanical design for the remainder of this build as much as possible… until I know more about how I might use it.
– David