Dual Rail - Center Mounter Stepper - cad prototyping

New year! The designs have finally started flowing again, \o/.

I’ve been imagining a single bed, double rail design for a months. This weekend I modeled and designed a prototype configuration.


I was able to reuse the Front Bracket from the Double Bed Double Rail design, with minor tweaks. For the Center Stepper Mounting Bracket, I took the Rear Stepper Mount Bracket from the Double Bed Double Rail and notched out 2 sides allowing the Linear Rail to fit, allowing clearance for the Linear Rail Carriages.

I wanted to a dual linear rail design, with a center mounted stepper. Moving the stepper from the end of the Y-Axis to the middle reduces the length but requires a nifty belt run. With the Stepper Pulley in the center, I used the existing hardpoints from the steppers to dictate the position of the the Two Idlers. I’m not sure the M3 screws are going to resist the fully tensioned belt, but that’s what testing is for.


A double idler pulley bracket was needed. Modifying one of my existing Pulley Tensioner Brackets, I created a bracket which supported two idlers spread 31mm apart to match the hole pattern of the Stepper.


Compared with the Double Rail Double Bed and Deltesian 1.1.x Bed, this new design is much more compact.


Surprisingly, this new design has the same 300mm rails and travel as the Deltesian 1.1.x Bed on the right.


Visualizing the design in a Deltesian 1.1.x XZ frame compared to the standard bed.

Visualizing the design in a Deltesian 1.1.x XZ frame compared to the standard bed a Y-min.


The view from above really drives home the change in footprint.

I’m very please with the overall look and size reduction. I’m not sure how the belt run will work in reality. With 6 idles now vs. 1 before, this belt run is much more complex and I’m expecting problems. Also the clearance are very tight. Most likely too tight, but I’ll see once everything is printed and assembled.

Until then!