Hi, I was wondering if you could give me an idea of the efficiency of a part. Right now I’m interested in anti-backlash nut part# 19664. I was thinking of using the mating stainless screw (part# 60986) but let me know if the efficiency will be any different for the regular steel version. I also had a question about the anti-backlash nut previously mentioned. I see that the operating load rating is 25 lb, and that the static load rating of a similar plastic sleeve nut is 1000 lb. I understand that there is less contact on the anti-backlash nut and therefore less material to support the load, but the difference (25 vs 1000) still seems pretty big. Does this mean that the 25 lb rating is based on the amount of resistance to backlash due to the preload of the spring? If I were to use it in an application in which, say, it was frequently exposed to 50 or 100 lb of force, would that be likely to damage the nut, or just compromise the anti-backlash capability? If this is the case, might it make sense in some cases to just buy 2 sleeve nuts and preload them relative to each other? (I’m guessing this would be less efficient, but it would take a much bigger load to damage it…)
The efficiency is the same for steel and stainless steel. Efficiency is a function of lead angle, flank angle and coefficient of friction only. Here’s a link to the formula webpage (see # 10): http://www.roton.com/formulas.aspx
The preloaded nut is de-rated because the preload is very light and only effective for small loads. There is also a limit due to the flange mounting. We do have users who load these beyond the catalog rating of 25 lbs. without any problems but each application has be to tested to make sure it meets the service life and performance requirements.
You can use two sleeve nuts and make a more robust anti-backlash mechanism if PN 19664 proves to be inadequate.