A slight modification to Gossamer's thing that adds sections with a narrow diameter at the bottom of the bolt head holes. This makes it less easy to install (you have to completely remove the bolts) but I think this will make it less likely to slip off the bolt heads if tension is high and helps spread the force from the bolt heads across a larger surface area preventing damage to the plywood or acrylic. In my case the bolts had already been over-tightened which lead to deformation of the plywood and cracks in the acrylic.
Note1: It might help to drill some 6mm holes in the left side panel of the printer so you can access the bolts holding the left end piece to the Y-Carriage without having to remove the Y-Rods and Y-Carriage. I made mine at the Y-Home position for easy repeatable location of the bolt heads (see picture).
Note2: A 4.4mm hole allows you to use the little clear plastic collars from the end of the ABP rollers as hole inserts with built in washers to protect the plywood from being damaged if you over-tighten the tension screw. If you do not have any of these to spare you should at least use a washer or two!
- Modify the .SCAD file changing "twice_z_resolution" to the value in mm of double that of a single layer of printed plastic.
- Print, cleanup, insert captive nut.
- Remove side panels/remove plywood parts/drill holes etc. so you can access the motor mount bolts and pass through the tensioner bolt (see parent file instructions for detailed help)
- Remove the 4x M3 bolts that hold the motors in place
- Insert printed piece and reinsert motor mount bolts, ensuring you do not tighten then too much
- Insert a bolt through the hole you have hopefully drilled in the right place on the rear panel for Y-belt or left end piece of Y-Carriage for X-belt
- Tighten tension bolt until you have the correct belt tension (if you want you can further tighten the motor mount bolts now)
- Re-attach any removed printer parts
- Print with higher speeds and better results!