I am building a tiny little spindle for PCB milling on my MiniMill.
- 3D Material Used:
- ABS
I used
1 x 775 RC Motor (5mm Shaft)
1 x 5mm Shaft ER11 Collet Adapter
1 x 3D printer Adapter to fit the OpenBuilds Spindle Mount
![]()
![]()
First, I printed the attached part: This adapts the 45mm motor body diameter, to the 71mm inside diameter of the OpenBuilds Spindle Mount
![]()
![]()
Here's the result:
![]()
Attach the ER11 Coupler onto the 775 Motor. Simply slip the motor into the adapter, and insert into your OpenBuilds Spindle Mount
![]()
![]()

775 Motor to OB Spindle Mount Adapter 1.0
ER11 -> 775 Motor -> OpenBuilds Spindle Mount