These mounts are for the x-axis motor and idler pulley mounts for the Tevo Tarantula 3D printer. These can be used in conjunction with the Tarantula's stock z-axis carriages or with custom z-axis carriages that do not incorporate mounts for the x-axis motor and pulleys.
There are two versions of the motor mount. One incorporates a lower appendage that can be used as an adjustable trigger for a z-min end stop. There is a place to embed a M3 lock nut in the bottom, and then you would use a long M3 screw to engage the z-min end stop.
If you are installing these with the Tarantula's stock z-axis carriages in place you will need 30mm M3 screws for the motor mount and 30mm M5 screws (or longer) for the idler pulleys. You may also want/need to make sure these brackets are fully seated on the aluminum extrusion -- you may need to adjust your z-carriages or drill new holes in the acrylic if the holes don't line up perfectly for your particular build.
I have added three new STLfiles that are for Rev2 of the idler pulley mount. This design incorporates a tensioner into the mount. To use this with the stock z-carriage on the idler side you will need two low profile M5 screws and two M5 locknuts for the pulley axles, and you will need one hex head M5 x 30mm screw, 1 or 2 M5 washers, a standard M5 hex nut and some light duty thread locker (e.g. LocTite Blue) for the tensioner mechanism.
Video of my dry run of this new design: https://youtu.be/UyyxU8uNeCY