Nema 17 Flexible shaft

thingiverse

Finally figured out an incredibly easy guide to making worm gears! So now here's my take on the flex drive extruders. There are two distinct worm gear sets. The one labeled 1-40 ratio is a 1:40 gear reduction to achieve the same resolution and power as the flex3drive. The unlabeled one is a 1:13 gear reduction designed for use with a Titan or Bondtech extruder, which already has a 1:3 reduction. This should result in a total gear reduction of 1:39, allowing it to perform similarly to the other worm drive with an ungeared extruder. However, there are still parts that need to be modeled to make this work. I've discovered a PTFE shaft on Amazon that's 4mm O.D. and 2.5mm I.D., which is perfect for fitting a 3/32" coated stainless steel wire rope/cable. Edit: Completely forgot to mention that this uses threaded inserts for M2 and M3 screws – 4x M2X6mm, 4x M3X6mm, and 2x M2X4mm. Additionally, you'll need two 5x8x2.5mm bearings. I believe I used these in earlier projects: https://www.amazon.com/5x8x2-5mm-Metal-Shielded-Bearings-MR85ZZ/dp/B019I3C4MQ/ref=sr_1_20?ie=UTF8&qid=1542311084&sr=8-20&keywords=5mm+bearing. If this doesn't work, I'll post an update. The goal is to find something that fits inside a 4mm PTFE tube. The instructions for creating your own worm gear are available here: https://imgur.com/a/UzLSB?fbclid=IwAR1BSC21u6nS84WB9XDvFAJJTpcNzj6kwcFWTRNCK5i58TgcOC_oXi2ApAc. Update: Taking it one step further towards the real deal! I discovered that Rhino doesn't produce accurate geometries when using sweep commands. The worm gear set wasn't correct, but I found a workaround by lofting, which took way too long but worked. The tolerances are tight enough, less than 0.001mm. I've also modified how the worm drive couples with a flex shaft. You should now be able to easily attach designs to fit any flex shaft. The coupler and bowden tube clamp are designed for a 2.2mm flex shaft used in RC boats and 4mm PTFE. I found a supplier that sells 1m flex shafts for $30 after shipping, and I ordered some for testing. You can also buy it in bulk on Alibaba if you want to make multiple units at a lower cost per unit. My current plan is to print the parts that I can print and have the worm and gear printed at high resolution in resin. The resin parts will then be cast and reproduced in a better resin for mechanical parts. This seems like the best method for producing them accurately, in larger numbers, and making replacements. You can always try 3D printing them, but you'll likely need PVA or HIPS supports and a 0.2mm nozzle. Let me know if you manage it.