UPDATED 2016/07/21: So after some further discussion on Facebook, the correct dimensions were provided and I have updated this carriage. I apologize for the previous error. I have created 2 models. The A model corrects the dimensions of the original. The B model has additional M3 holes to allow mounting the NEMA17 directly to the carriage.
If you make this and have it working, please show a Make of it. If you still have issues, please let me know and provide dimensions so I can properly correct it. Thanks.
I designed this carriage for the TEVO Tarantula so it can mount the Toranado 1.1 Precision Geared Extruder found at:
The 4 hole version should also be compatible with the Prusa i3 attachments.
This carriage is designed to be vertically mounted on the TEVO Tarantula 2040 rail and will only work on like printers. I have been informed that the TEVO Tarantula's rails may not be 100% compatible with the OpenBuilds rails. The TEVO rails are not V-slot like the OpenBuilds rails and so it will not be compatible with OpenBuilds 2040 rails.
I do not have a TEVO Tarantula so I am unable to test this. However, the same wheel spacing was used on my other 2020 carriages so it should work.
This is not intended to be a swap out for the stock TEVO Tarantula which is mounted horizontally by design.
The screws to attach the Toranado should be round with short heads so that the screws don't interfere with the rail.
There is a very thin layer in the larger holes that can be cut or drilled out so that a bridge can be created to print the counter-sink without supports.
Use M5 screws with OpenBuilds wheels. Requires 2 eccentric spacers for the larger holes.
Prefer to use a stiff filament plastic like ASA or ABS or similar.