Z Axis Guide

thingiverse

I didn't have a lot of luck with the cantilever Z axis on the D-Bot printer. Here's a design that positions the guide wheels between the side supports and has a wider spread on them. The installation only requires that the beam be square to the upright and a slight amount of pressure against the supports by all four wheels. This setup is rock solid, and the stepper motor now mounts in the middle of the support. A spacer is included for this setup so that the stepper and lead nut mount in the same plane. Five millimeter by sixteen screws are needed to attach the spacer and the nut holder. Be careful not to overtighten the bolts that capture the wheels. Only a small amount of pressure is needed to keep the inner race from turning. I haven't worked out the homing switch because I'm using a sensor. The end supports use the cantilever arms. Two new pieces are needed across the ends to support the bed. If the stepper cross mount from the bottom is used as one, only one piece is needed. A person might be able to just use four stubs for bed mounting. If you saved your scraps from the original build, this can be done using the original back support and the longest scrap. Lastly, there is no adjuster for the wheel pressure. I am tossing ideas around in my head and may come up with something. I'm trying not to come up with something that would cause a reprint. Hence, the stepper nut spacer. Update 11/2/17: You will lose about sixteen millimeters of y-axis using this arrangement. I'm working on a fix for that but in the meantime, I'm using a spacer behind my bed mount to recapture part of it. Update 11/08/17: I took a different approach with this addition. Use one of each of the new items on a side. One piece has a cap that will rest against the beam while the other is open and can be moved to adjust the wheel pressure. My plans were to try spring loading that piece, but I don't think they will move easily enough. Not giving up though. Adjusters are coming!!!