The original improved Y axis belt tensioner is great but only works with the smooth idler shipped with the Mk4 because the genuine Gates toothed idler is 1mm wider. This modification increases the width of the idler cavity from 10mm to 10.5mm to fit the wider toothed idler and also reduces the other dimension of the cavity from 19mm to 17mm because the toothed idler's diameter is 2mm less than that of the smooth.
This is the genuine Gates idler used to model the new cavity: https://www.filastruder.com/products/gates-2gt-idler?variant=32673878442055
Only the housing needed to be modified for toothed gears. Please download the retainer and nut from the original project: https://www.printables.com/model/585494-prusa-mk4-y-axis-belt-tensioner
The author remixed this model.
The original improved Y axis belt tensioner is great but only works with the smooth idler shipped with the Mk4 because the genuine Gates toothed idler is 1mm wider. This modification increases the width of the idler cavity from 10mm to 10.5mm to fit the wider toothed idler and also reduces the other dimension of the cavity from 19mm to 17mm because the toothed idler's diameter is 2mm less than that of the smooth.
This is the genuine Gates idler used to model the new cavity: https://www.filastruder.com/products/gates-2gt-idler?variant=32673878442055