Hi all, new here.

Hi all, new here.

I’m about to start a build of something similar to the Mantis 9.1 (but scaled to support a minimum of 8"x11").

One thing that is never clear in all the online docs I saw about DIY CNC is how to attach the threaded rod to the step motor. Anyone has docs or exemples on that and what parts to use ?


The most common, and straight forward way is to use a flexible coupler. These typically have two different bore configurations: Where bore A would be something like 5mm (to fit a nema17 stepper motor shaft) and bore B would be 8mm (to fit an 8mm threaded rod). But they come in a variety of configurations.

I have seen DIY solutions where you use a piece of clear plastic tubing (from a hardware store) along with two hose clamps.

I prefer the flexible couplers. You can generally pick them up for between $5-$10 each.

If you’re looking for a suggestion of somewhere to buy them, let me know. In the true spirit of this group, I don’t want to seem like I’m spamming the list with links to my store :slight_smile:


Thanks Ed for the tips. Please feel free to send the links in private if you would prefer.

I’m also wondering, as I’m more equipped for woodworking than metalworking what you would think (for a first build) about using wood dowels (large enough diameter to avoid flexing) for the guide rails?
I’m pretty sure the flex in a length of 10 to 16 inch should be fairly minimal is not null.
Only thing I could see is the linear movement friction…

I think the amount of variance in a wooden dowel (swelling/shrinking) would pose a problem, also, the amount of wear that would occur in a very short amount of time would be significantly higher than if you were to use a traditional material such as drill rod, or hardened steel.

With that said: If you could somehow make guide rails from wood it would be super cool! Although, I can’t think of a way to make a long term solution out of it.

Good luck!


True about the wear. ‘standard’ wood dowels are usually pine which is quite soft, but using birch, maple or oak could be pretty good.
A 1/2" dimeter birch dowel is about 0.75$/ft :wink: