Which thread has more friction. 2

[dennis45]

If I have a motor with a 1/2-10 acme thread that drives a lead screw and another motor with a 3/4-10 screw, which screw would cause the most friction/resistance for my motor? Would more thread surface area be good or bad in this case. Any help or insite would be greatly appreciated.

Thanks

 

[poetix99]

Do a keyword search on this website for previous threads which have discussed the same topic.

Check some "standard" mech engr. texts, such as Marks' Hndbk, and Lindberg (spellling?). There are at least two different definitions of torque coefficient (different from friction coefficient) each of which is a function of thread geometry among other parameters. So, there ought to be a difference between your two choices. Let's hope that it is consistent from one calculation to the other...

 

[xyzpdq]

Look at the efficiency rating of the screw you are choosing. It should be listed in the catalog. the lower the efficiency, the higher the friction. In the catalog that I use (nook brand), the 1/2"-10 is 34%, and the 3/4"-10 is 25% (using a bronze nut).

 

[vinodkagarwal]

Dear dennis45

Friction of Screw or bolt will be high if they have less pitch & more dia.

 

[ornerynorsk]

Acme threads move heavy loads easier than "typical" v-threads. I do not know the mechanics behind it, I just know this from practical experience. Lubrication is also a very important factor.