Delrin 500AF vs 500CL

[booster9000]

Hi,
I plan to use Delrin 500AF for a leadscrew nut. This has teflon for lubrication and in general has the right qualities. 500CL is 'chemically' lubricated. I am looking for guidance as to which grade might be more appropriate e.g. when would one use CL grade?

 

[mcgyvr]

DELRIN® 500AF Injection DELRIN® 500AF is a 20% TEFLON® fibre filled, medium Speciality friction and wear applications,
moulding viscosity acetal resin for injection moulding. It is well conveyor systems.
suited for low wear, low friction applications.

DELRIN® 500CL Injection DELRIN® 500CL is an unreinforced, medium viscosity, Gears, drive trains, sliding devices.
moulding lubricated acetal resin for injection moulding. It is well
suited for low wear, low friction against metals.

http://www2.dupont.com/Plastics/en_US/Products/Delrin/delrin_amer_design.html