Bánh răng lớn cho gọt bút chì Boston

This gear was made with the help of STLGears.com  I chose a spur gear with these design parameters.

The circular hole is just to know where the center is.  I then import the file, scaled for the proper diameter (Spur_M0.7_Pa20_Z71-2mm-ch-5487.stl) into Openscad to add the hub and the rectangular cutout. 

The Spur_M0.7_Pa20_Z71-2mm-ch-5487.stl file needs to be in the same directory as the large-gear.scad file should you wish to make some adjustments.

The file to use is large-gear-shaft-fit-v4.stl

I used PLA with 4 perimeters and 15% honeycomb infill.  The gear fits tightly on the rectangular shaft and a generous amount of white lithium grease is added to both gears.