MK3S+ Bear Bondtech Mosquito & Hiwin Linear y Rails 9mm y Belt questions
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MK3S+ Bear Bondtech Mosquito & Hiwin Linear y Rails 9mm y Belt questions  

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MK3S+ Bear Bondtech Mosquito & Hiwin Linear y Rails 9mm y Belt questions


I hope to keep this short and on the spot. Setup mostly already in the headline with the following troubles / questions:


  • Mk3s+
  • Bear Frame w/o Bear Exxa
  • Bondetech Mosquito
  • Y Axis Hiwin Rails on original Carriage with two rails and three carts. 
  • Z Top LED Rig
  • FW 3.9.3 from Bondtech Website

in this config the printer ran very well, also did not have issues with calibrations or selftest

Then upgraded to the 9mm genuine Gates belt, teethd idler and the 20 T pulley. As internet suggests, knockoff pulleys and idlers are doing more harm then good, and as Gates daoes not offer a 16t for the 9mm belt, I went through the steps of changing the Setps for Z from 100 to 80 as per internet instructions. 

  • m503 to read the values
  • m92 y80 to set the steps
  • m500 to save
  • m503 to validate values are there (once more after a reboot)
  • also repeated the whole process after a full factory reset and FW install.

Printed passes selftest for all axis and finds autohome. xyz calibration fails in the following manner:

going well all the way to the 4 point calbration on the third point, the nozzle doesnt crash the bed, pinda cruising around the calbration mark and then moving on after some time until it gets to point 3.

on the first few "loops" around point three, it crashes 2 or 3 times into the "front", i.e. y moves too far towards the lcd. (left Hiwin cart into the railholder), then it seems to home in on point three as it normally would and then moves to point 4. On Point 4 it does not crahs into the front, seems to start calibrating fine, and then stops which feels like about 50% of the time it takes for point 4 to finish with "xyz failed, please consult...". 

I did check the calibration results on the LCD, for the Y axis length it reads "nan", for the tilt it reads 0.22 (or 0.022), but below the max threshold for severe tilt per LCD screen value.

Pulley is properly fixed to the motor, belt runs straight. Belttest comes back around 245 for both, y Table is in the middle of the frame

Questions on this:

  • Did I miss some FW or other adjustment?
  • Rationale for the 20T Gates pulley -> if this upgrade is to make sense, it has to be done right, i.e. correct hardware. The fact that gates does not have a 16t 9mm pulley, tells me, that the smart people at gates probably have a engineering reason for this, hence the 20T pulley. Does this logic hold with users having more experience than me?
  • Is it worth pursuing this upgrade at all, or just forget about it and put the 6mm back on with the 16T? 

Thanks in advance


Posted : 11/05/2021 11:45 am