Mendel Alternate X Motor Bracket

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Improved X bracket

Release status: Working

A re-design of the Mendel X motor support that is kinder on the X toothed belt
CAD Models
External Link



The previous Mendel X bracket was compact, but led the toothed belt along a tortuous path with tight radii and reverses of direction. This could cause belts eventually to fail. This design is larger, but less prone to belt failure. It's in the alternative parts section of the distribution (mendel/mechanics/solid-models/cartesian-robot-m4/printed-parts/alternative-parts/) and is simple to print and to fit.


Name Qty/assembly Total Qty Type
xaxis-motorbracket_1off.par 1 1 RP
m3-capx20.par 8 8 Fastener
m3-capx12.par 4 4 Fastener
m3-nylock.par 8 8 Fastener
m3-washer.par 20 20 Fastener
m4x16-cap.par 2 2 Fastener
m4-nylock 2 2 Fastener
m4-washer.par 6 6 Fastener
m5-mudguard-washer.par 2 2 Fastener
624-bearing 2 2 Bearing
stepper-motor-nema17-fl42sth47-1684A-01.par 1 1 Motor




The X-axis ground rods need to be 32 mm shorter than the original length for this design (that is, they are 463 mm long). If you are retro-fitting, don't try and cut them while they are on the machine - you'll make a hell of a mess. Slacken all the screws that hold them and they will slide out towards the motor end quite easily. Take one out, cut it, and put it back. Then do the other one. Things will stay together better that way.

The belt teeth face inwards with this design (rather than outwards as they do on the original Mendel). This means that the motor needs to turn in the opposite direction; simply reverse the order of its four leads into the stepper-motor controller.

Other changes are: -

  • The x-motor-bracket-spacers are no longer needed.
  • The axis uses two fewer M4 bearings and associated washers and fasteners.
  • The motor is attached by four shorter M3 x 12 cap screws not on the original BOM.

The picture above shows the old-style drive pulley. You should definitely use the newer set-screw design in preference to this for a new machine.