Uprated Universal Adjustable Belt Tensioner

After running my original universal tensioners for years, I changed over to extra-stiff GT3 belts and needed a little more “oomph” to get them up to spec.  This reinforced double-bend tensioner was the result.  Sized for 6mm belts, but can be Z-scaled as needed for other belt widths.

Printing:

• I used PLA and 4 perimeters.
• 0.1mm LH suggested.
• No supports needed.

Materials:

• 2-part Epoxy (such as 5-minute Gorilla)
• 1.5mm Carbon Fiber rod (I like WindcatcherRC) – OR substitute 2x ~1.5mm diameter x 53+mm long finish nails with the heads and points clipped off
• Zip ties

Assembly:

1. Use the included cutting jig print to cut two CF rods at the correct length.  CUT THE CF WET FOR SAFETY (rolling the rod under a utility blade on a cutting mat layered with wet paper towel works well).
2. Then epoxy the rods into the slot as shown in the pictures.  Tip: A quick rubdown with a cotton pad or paper towel soaked in IPA within 10 minutes of starting is a great way to clean up any stray epoxy.
3. For best results, allow 24-48 hrs for full epoxy cure before mounting and tensioning.

Mounting and Tensioning:

Thread the zip ties through the small part first, then through the rounded side of the large part.  Place the parts on either side of the the belt, and finally feed the zip tie into its locking head and pull tight. Adding tension is easiest if you pinch the parts together with one hand while pulling on the zip tie with the other – possibly with the aid of pliers!