[ssashton]

Hi all,

Could I get a little help choosing belts and pulleys to connect my 2.3Nm Nema23 steppers to the 16mm ball screws, please?

I want a 1:1 ratio. The motors have 6.3mm dia. shafts and the ball screws have 10mm shafts. The centre to centre distance is 222mm for one arrangement and 62mm for another. The shaft lengths are about 13mm.

There are so many pulley and belt options (HTD / Vs GT2, pitch, width) I'm rather lost! It would presumably be good to choose a pulley size that lets me use a standard closed loop belt size (if such exists?).

I have another question - If for example I use HTD 3m 24tooth pulleys on the 222mm centre spacing, this gives a loop distance of 517mm. Does this mean in practice I'll need a slightly longer belt and a means to tension it? How much adjustment in centre spacing is usually nessicary?

The 62mm arrangement has a sliding motor mount that allows about 3mm travel. The 222mm arrangement currently has no means to tension, but I plan to add an adjustable idler if nessicary.

Thanks very much!

[peteeng]

Hi Sash ::
1) availability of belts in your area drives the decision on what section to use. Use the widest belt/pulley that fits on your motor shaft. If you have a 1/4" shaft this will be 16mm or 25mm. Many people use the HTD & GT but where I am in australia AT & A are easy to get so I use AT.
2) I use a 10mm adjustment mechanism on my belts. One end I have a coarse slot (which I pull up by hand) then a screw adjuster. Its best not to use an idler wheel for tensioning just use a slide at one end. But if you have to use an idler so be it. I'd expect if the belt is correct length 5mm adjustment would be fine...
3) a tight belt is a good belt so make the adjustment as long as possible to ensure it will pull up... Peter

[ssashton]

Thanks Pete.