Every single rope tensioner i have tried has failed, so i have designed my own. Fixed many issues from other designs

No points of high stress - Have not done long term tests, but with prior experience, PLA will easily stand up to long periods of high tension

Use more layer outlines depending on expected load
Please print a tensioner where the rope barely fits through the hole (for proper pinching)

XS AND S TEETH WILL NOT PRINT PROPERLY WITH FDM PRINTERS*
For this situation, Print “Without Teeth”. This still has the lip, but without the cut out triangles.

M Teeth and L Teeth will also have issues with a large nozzle (0.3mm+)

(T) = has Teeth
(WT) = Without Teeth
(WL) = Without Lip 

Hole sizes: 
XS diameter: 4.8mm
S diameter: 7.2mm
M diameter: 8.4mm
L diameter: 9.6mm
Please use a tensioner size that just barely fits the rope 

(i also suggest scaling up or down in slicer to fit your rope)

.step files provided if you want to edit or remix the model