On Sat, 31 Jan 2009 09:35:42 -0500, "Garland Gray"
wrote:

I need to replace some old plastic sheaves, and I have the option of sheaves
made of Delrin, acetal, or glass filled nylon. (I have learned that delrin
is acetal, but don't know if all acetal sheaves are delrin).
So what are the relative attributes of acetal and glass filled nylon
sheaves? I read somewhere that GFN might be more abrasive on the pin, but I
assume that it is stronger. Ronstan sells both, but their website doesn't
solicit questions.

Why not give Ronstan or your local rigger a call and find out the pros
and cons of each?