Foolproof belt tensioners needed

Not anymore. :frowning_face:

The file I linked above should might work without any modifications to the Y plate.

Hmmm. What material would be suitable for such a design? I’ve never done any 3-D printing.

Hey @Dr.Angus,
I’ll get some printed today or tomorrow and send 'em your way. You’ll need two 16mm M3 screws, two M3 nuts, one M5 nut and one M5 screw (length depends on your placement). Probably good to have an M5 washer as well (or just mill one out of scrap as thickness wouldn’t matter).

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Fantastic! Many thanks.

No problem. You’re the beta tester…I have not had a chance to test yet.
Also, I just realized this is the main thread and not the PM. Oops.

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What sort of sustained tension do you think those are good for?

(Assuming we’re staying in the sensible region belt tensions which don’t torture stepper motors)

No Idea. I think the outside-the-plate mounted version is ideal, but most dont have a slot in the plates.

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Yep, I have been considering that adjustment to my steel plates…

May I suggest that a beta user of the printed clamps could install the carbon drive app and measure belt tension on installation and then a week / a month later to see if it creeps?

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As a beta tester, I plan on using both the Gates Carbon Drive app and portable “luggage scale” method of determining creep, etc.

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Excellent, I look forward to the results, the belt clippy things are a pain and really hard to get good adjustment with. On my XXL there is a working static extension range of 1 to 2 belt teeth on the clip without getting into stepper torturing tensions which is a bit binary.

Julien’s suggestion of using 1/4inch cutter shanks to hold the belt up is good, the less the belt is pulled up for the frequency test the less change there is from the static tension. I only use the frequency test now as it seems more repeatable to me and it’s quicker and easier to do.

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@Dr.Angus How are the tensioners working for you?

Well, I don’t know. The wildfires here have been so bad that the air quality index today was 592, WAY off the chart, and you can’t be outside or in the garage without coughing and getting itchy eyes. The Shapeoko is in the garage, unfortunately. The weather forecasts are for some change in the patterns starting next week.

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Oh man… Please stay safe.

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I have actually been debating doing this by hand. Basically carefully drill a hole through the plate and then use a micro file to open the hole up. In my opinion the belt tensioner should be on the outside face of the plate. This allows for more clearance to the v-wheels on the carriage and a better system for doing the tensioning. The tensioner could be attached using the top two holes used for connecting the cross member to the plate.

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I agree. The problem is drilling the holes and widening to an appropriate slot…three times.

Yep. Though I am thinking of 3D printing a guide for aligning the holes properly.

Excellent idea. Maybe one that incorporates a steel drilling collar so the drill wouldn’t damage the plastic.

Possibly, though for three holes that might not really be necessary.

For three holes you only really need a locator for a centre punch so you can accurately place a centre drill for the initial cut.