Ok, sorry for the delay, here are the 2 3d printed pieces:
Pulley Mount for D-bot z transmission by tmproff
Cbeam Endmount by tmproff
The Cbeam endmount just uses a standard 608 bearings (8mm ID)
Yes, I'm using 20 tooth pulleys for the x/y
for the leadscrews, I use these : https://www.amazon.com/gp/product/B017AR5QBS/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
here is the stepper and driver I used:
https://www.amazon.com/gp/product/B019MFIOD8/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B016ZJS1FA/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

I'm not sure the belt length for the z, If I had to guess, it's around 1700mm

 

Nope, they dont move at all.

 

I used these:
D-bot linear rail upgrade kit by Tick007

 

Wow! I love it. This is actually an improvement since the vertical attach midway up.

Also, I switched to the top pieces that used aluminum plates. Adds a lot of rigidity:
D-BOT - ALUMINUM CORNERS - MGN12H by ahntorage

 

I used MGN12 https://www.amazon.com/gp/product/B077MFSF5F/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

 

Have you figured out where to put your z motor? Are you going to use gear reduction or bigger stepper like l did?

 

Ok, I had an epiphany last night on a clean way to drive the z axis without using a Nema 23 / external driver and reduces the belt path quite a bit. I originally had my bed (which is quite large and heavy - 1/4 MIC 6 aluminum plate 15"x15") being driven by a single Nema 17 but using reduced gear ratio of 3:1. It had no problems moving the bed up and down. What do you think of this? You can slide the stepper mount along the 20x40 rail to add tension, no idler pulleys necessary. Also, no need for that long 20x80 piece between the 2 Cbeams

 

It would be quite easy to add an idler between those to pulleys to increase the contact, but it shouldn't be necessary. I'm going to be trying it out this weekend on a new D-bot build, and I'll take some pictures.

 

Just so you know, the new idea still uses a single stepper, but instead of a Nema 23 + external stepper, it will use a single Nema 17 that is driven off your main control board. The torque is there due to the gear ratio of 3:1. Overall, it's just a simpler design.

 

Ok, got it hooked up. Works very well!

 

Progress this weekend:

 

This is a new printer im making for a co worker. He can upgrade rails / extruder in the future if he wants.

 

Controller came in the mail last night...got XYZ moving..still waiting for the MIC6 plate to come in the mail.

 

Printer is finally done. Delivery to new owner today!

 

So I'm not happy with the solutions out there for D-bot carriages + linear rails + Titan Aero so I am designing my own. I'm going to cut the front / back out of aluminum (using my CNC machine), and tap all of the holes so no need for locknuts on the back. Here is what I have in mind. What do you think?

 

I dont remember exactly the lengths of the 4 vertical pieces, but for the horizontal, I just used 500mm since they came from Openbuilds cut to that length for convenience (I did shave off a small portion to make sure all the horizontal pieces were exactly the same length). For the 4 vertical pieces, I started with 1000mm pieces and cut them down to about 750 I believe.