Greenwatts

LM339 Gear Housing Top

Take a piece of flat ABS stock to make the top of the drive housing and estimate where the hole needs to be drilled for the spur gear shaft allowing for overhang on all four sides of the drive housing which will be trimmed off later. Drill a hole slightly larger than the 3/8 shaft diameter that will fit over the spur gear shaft. Making sure the spur gear shaft is perfectly vertical, tack cement the top of the drive housing into place. Now mark the under side of the housing top on all four sides, remove it and trim it. Make sure to mark which side is up and after trimming it place it back in the same position and securely cement it into place.