Some photos of a couple other changes to my PP. I replaced the 7/16 rods with 1/2" Precision-Ground Case-hardened steel and PTFE flange bushings (from McMaster-Carr).
I also moved the idler sprocket (from the MK1.5 kit) to the position between the top and bottom block, without changing the height of the sprocket. My idler was leaning toward the gantry at the top, also.
Oh yeah, I installed a 1/4" tall spacer (tube) onto the 1/4" shaft, above the sprocket, to keep it from rubbing against the bearing block.
That causes an interference with the gantry, so I sawed a 1/2" tall X 1 1/2" wide piece of MDF from the offending area.
I also added a small piece of aluminum extrusion atop the outboard end of the Y-stepper, to hold it down and add some screw-tensioners for adjusting the belt. The motor still slides left/right, but the screws do all the tensioning work for me. The photos are fuzzy, but I think you can see what I did. Attached files

 

Nice work!

Anyone with the MK1.5 Belt drive mod really needs to do this.

The bearing block just cannot absorb the constant tension being applied to it the way that Eric recommends installing it.

I also like how you made the tension adjustment but many of us would not have the tools to make the tensioner. Business opportunity there...

 

Flashsolutions, The only "tools" I used were a hacksaw to make the aluminum extrusion the right length, a drum-sander on the Dremel to make the cutout for the pulley, a drill to make the 1/4" holes for the screws and a tap drill and tap for the #10-32 screws. If the photo wasn't so %^#$% fuzzy you could easily see the "non-machine-shop, non-standard practices" that I used.

 

heheheheh, well it looks pretty professional with all that fuzzzzz

 

Naaa - the professional ones either have no fuzz at all, or a topiary. :?: :?:

 

Thanks for the compliments Mark.
I post my photos to help others take up their hacksaw and wood-rasp to make their PP do what THEY want, also. And maybe they can show me how I should have done it, because around here the first innovator doesn't stand a chance!

 

WARNING!!!
For anyone who was thinking about installing a micro-switch like I did to turn the Dremel on and off, DON'T DO IT! Maybe it finally reared it's ugly face with age, but the electrical noise when the switch disconnects the motor is causing my SmoothStepper to lose communication with the Easy-CNC controller board, and the system stops in mid-cut.
Mach freezes up, and the only way to get it back working (except forcing a hard re-boot) is to unplug the SmoothStepper USB cable, causing Mach to post a "Lost connection" message and allowing me to restart them both.
I don't know if it's the limit switch wires or the stepper motor wires that are receiving the noise, but as a temporary fix (until I get a set of shielded wires installed), I just disconnected the micro-switch from the Dremel and installed a jumper to complete the motor circuit. Now I just plug the Dremel in before I start the cut and un-plug it when the cut is done. BTW, the way I finally realized the problem is that I installed a "light pipe" so I can see the lights on the SmoothStepper, when the metal case is closed. I noticed the red "data transfer" light on the SmoothStepper had gone out when it froze up - every time.
I guess I need to find one of those small relays to control the Dremel, after all.