Idea to reduce steppers to 3 instead of 5

Hi Guys,

I had this idea how to reduce the number of required steppers from 5 to 3…
The idea is to run an 8mm threaded rod through the x and y axis tubes.
The rod has skatebearings at each end that are mounted inside the tube (might be a bottleneck there…)
The rod will have 2 timing belt pulleys on one side and 1 on the other.
The stepper will drive the rod wich in turn will drive the two timing belt pulleys.

I hope this idea will be usefull to someone…

Best regards,


Interesting. I wonder how much flex/backlash there would be in 30" of threaded rod. You might be able to get away with a printed “bearing” instead of trying to find the right size that fits in the tube. Are there pulleys that mount straight to rod like that readily available?

Another advantage is that the two sides would stay in sync, even with skipped steps, so that the machine would stay square after poweroff. The trouble is you’d have to get them aligned, but only once.

That was the original plan but back then only the little nema 42’s were cheaply available and didn’t have enough power.

Now I get weekly questions about how to use nema 23’s…so I believe the larger 17’s that we now use are strong enough, for me it isn’t worth the time to make new parts since people don’t believe it is strong enough as is.

Awesome thinking though… Great minds think alike!

“Awesome thinking though… Great minds think alike!” - thanks for the compliment!

I can imagine that you don’t feel like redesigning, but maybe someone else can design this as an add-on.

Thanks for this great design. It’s one of the best I’ve seen in a very long time!

Best regards,