Marv,
Quite certain it is right hand thread. One caution about impact driving slotted screws is to use a tough tight fitting bit.
There are purpose built manual impact drivers that when hit with a hammer can usually convince the most stubborn screw.
Try to find one of those.
This is an example http://www.amazon.ca/TEKTON-2905-8-...45386971&sr=8-2&keywords=manual+impact+driver
Can't locate it now but I saw a video with a person making a new gib of a tapered type. It installed and removed parallel to the axis on which it was installed.
Is this such a gib, Marv?
- there should be a screw or screws to move it in and out of the slide, it's tapered so it can only be removed one way and the screws can lock up the slide if it's adjusted too tight.
... you may even need to take out whatever's obstructing access to the thin end and use a very long, very thin drift to punch it towards the wider end of the space... .
Good luck
Use a flat blade screwdriver. Tapping the screwdriver with a hammer while turning might help. Some of your ATF/acetone mix would be in order here.
Also there could be two screws here, the one you see right now, and maybe one behind it. The one you see may be a lock screw.
At this point... as I understand it, all I have to do is remove the nut from the hand wheel & the whole cross feed table can be pulled off the front... Correct?