Black Widow X-axis tensioner by MODesign

Last crawled date: 3 years ago

30/07/2017 4th revision and a change of vision behind the concept.
Triple pins are completely removed, replaced by 2 side arms.
To prevent lifting/raising of the ram while the tension is being applied I've added a 'hood' holding it down, with 2 additional guides.
Sizes of slots vs arms are adjusted by 0.2mm, should work right after printing without a need for filing to fine tune it.
Overall model got simplified for ease of printing, same hardware required.
10/05/2017 After some feedback from a fellow community member regarding pins snapping, I've updated the model with thicker, wider pins
After few revisions and tests, it's cooked up well enough to be shared.
It's an X-axis tensioner element intended specifically for TEVO Black Widow, it may work for other printers of similar construction but I couldn't tell.
Instead of replacing the existing aluminium part with a mounted pulley wheel, I decided instead to just give it a helping hand - don't trust the plastic part with reliably dealing with applied tension on ongoing basis.
The idea behind it is to serve as a piston, adding more pressure to fine tune the tension after you have applied what tension you could with your bare hands.
Hardware needed:
2x M6 screw, round head, hex
2x M6 nut
2x 15mm M5 screw, round head, hex (I'm using 15mm low profile screws)
2x M5 T nut
First, position the pulley plate as far as you can on your own, tighten the screws.
Now, with M6 screws retracted, position the tensioner with it's piston touching the pulley plate, tighten the screws so it no longer moves.
Loosen up the screws of the original plate
Using an allen key (5mm in my case) start pushing the piston further until you're satisfied with the resulting tension
When done, tighten the screws of the pulley plate
Keep in mind the limits of your hardware!
The belt, held in many cases only by teeth facing each other pressed together by cable ties can and will slip out if pushed too far (it did for me on first try!), so that's your first limit to consider - and don't forget, on the other end you're applying this pressure directly to the shaft of the motor, so use common sense please.
Enjoy!