From a plastic supplier:
Delrin behaves like most engineering materials in that as temperature increases, elongation increases and strength decreases. Delrin has a tensile strength at room temperature of 10,000 psi, no true yield point and a stiff flexural modulus of 410,000 psi.
Delrin has outstanding fatigue resistance, almost indefinitely withstanding cyclic compressive/tensile stressing 5,000 psi.
Delrin does not permanently deform or retain dents, and has good impact toughness. The higher molecular weight resin formulations will deliver even greater toughness.
The Delrin-steel coefficient of friction is very low (0.1-0.3), and friction values remain virtually unchanged over a wide range of temperatures, loads and relative surface speeds
Sounds like more spacers should use this material.