This upgrade of ToyREP will allow you to attach 40x40x10mm fans close to X, Y and E motor for better cooling and reliability. Fans may even let you use a bit higher print speeds. These models are prepared for 28BYJ-48 with four mounting holes but are also backward compatible with more common motors with two holes only. Models should work, although I did not print them my self yet. My fans are already glued to similar positions, so I don't need this upgrade :D. And I don't have motors with four mounting holes at home either. They are marked as work-in-progress unless somebody will prove them working. 2015-09-02 2015-08-29 2015-08-24 It is pretty simple. Print these parts instead of the one attached to ToyREP. Use either Extruder_Rev2 for common motors with two mounting holes (looks better and aligned) or Extruder_Rev3 for motors with four mounting holes (dirty fix). Add 3 pcs of 40x40x10mm fans and 6 pcs of 3x20-25mm woo screws. Attach each fan by two screws above every steper motor. Connect the fan cables either to free pins for endstops on RAMPS (than they will run at 5V from USB power socket) or directly to the 12V PSU. Each motor will be attached by only two 3x13mm wood screews (already counted in BoM). For motor with two mounting holes use openings closer to the centre of the motor. For motors with four mounting holes use openings closer to the the blue plastic cap. Print X1_M8 and X2_M8 instead of X1&2 for quicker Z movement. In BoM replace two M5x250mm threaded rods and two M5 hex nuts by two M8x250mm and two M8 hex nuts. The rest of the vitamins remains the same.