Ted Edwards writes:

Teflon will cold flow so doesn't work well anywhere significant
pressure is involved.

Despite this oft-heard glib dismissal, plain Teflon (PTFE) works well for
reconstructing machine tool ways.

"Cold flow" is a misnomer. The phenomenon is properly called creep, an odd
mechanical property where the yield strength for plastic deformation is a
function ot time. But for PTFE, this is still only significant only at
1000s of psi, which is not present in ways.

Machine tool bearing surfaces do not typically exceed more than a few 100s
of psi transiently, and much less statically. This is by design to ensure
rigidity and lubrication. This makes them good candidates for PTFE
rebuilding. Indeed, machine ways are carefully designed to ensure that
forces are never concentrated anywhere on the bearing surfaces. The same
principle fits PTFE properties quite well.