Capt., Thanks . I now have a starting point . Todd it is ! I want to replace the plastic parts in my sliders rather than replace the whole $$$ unit . The pieces that remain in the units are just that pieces . I think I can reproduce them with starboard, if I can't find the extrusions. I can mill them with my drill press. (don't laugh) I have good luck machining stuff using my milling tools and the right fixture. In my prior life before retirement I was/am a Card Carrying, Journeyman Machine Repairman. ( Millwright) I once mated a 72 ted Williams 3.5 hp outboard motor, exhaust housing to a 77 ted w. 5.0 hp powerhead using my drill press to machine the plates .