Trussed Mendelmax Y belt tensioner
by bluecoast, published
This is a stronger trussed Y-belt tensioner with double tensioning screws to provide some belt tracking control. It's an iteration of kludgineer's Mendelmax 1.5 part.
I have a heavy Y assembly and am trying to use as high a belt tension as possible, maybe even with a wider belt in future. Anyway, my (over)tensioning bent Simonious' wider version of the Mendelmax 1.5 Y belt tensioner, and once the bending started, the belt always rode to one side and dragged. This part is intended to fix both the bending and lack of tracking adjustment -- now the bearing shaft rides in two trusses that span directly from the hinge pin to their own tensioning screw. I also hexed out the bottoms of the hinge nut pockets since they're in the middle of the truss. It now looks plenty strong for my purposes (a bit like a plastic valve rocker).
Update: I uploaded new files with a 0.2mm bridging membrane across the tensioner nut traps. You'll have to drill or break that out.
On disassembling my old tensioner, I found a very oval mounting bracket hole was part of the tracking problem -- high tension is going to need a new bracket as well. It was easy however to dial in the tracking after installing the new tensioner in the old bracket.
I am just trying out the first one of these; I can see a few things I might want to improve so I'm listing it as a work in progress.
It matches the original Mendelmax 1.5 bracket -- Simonious' similar bracket is a bit wider (it's what I have actually) and needs washers at the hinge to work. I will probably make a beefier bracket to go with it at some point.
Use the longest screws you can for the hinge pin -- there will more play with shorter screws.