COEFFICENT OF FRICTION OF DIRTY GREASE

[KJM]

Can anyone tell me what the coefficient of friction would be on a steel shaft with dirty grease? We know that without grease it is .8 and with clean grease it's .16. Any help would be appreciated.

 

[Carburize]

It depends how dirty!
I suspect that before any significant change could be noted in the friction coefficient damage would be caused by debris particles scoring the surface of the shaft

 

[Metalguy]

I suspect it depends on the size(s) of the dirt. Since you already know the coefs. dry and with clean grease, can't you measure whatever dirty grease you have?