Wondered what suggestions there might be for using a tape type of product, would it be best to wrap a washer, steel or engineering polymer with a couple of windings & use it like that? With the possibility of some rotational movement between components would it be prone to 'bunching up' or even being scoured away with use? Ultra high molecular weight tape might be good but nylon comes in many grades so maybe it's still be a suitable candidate. Delrin is funny stuff to machine but it can be cut cleanly but as you say not everyone has a lathe & off the shelf components are the way to go.