I have played with my blade clamp set screw and thumb screw so much I don't know which end is up--My question is how far into the clamping area does the set screw go? I am having a heck of a time with my lower blade clamp on my excalibur ex-21. I end up bottom feeding once I get the blade clamped but is pain to try to find the drill holes--any ideas out there---Richard aka thumbs