04-28-2014, 09:44 AM
Ed, that thing looks like it was made as an afterthought. ;) I can only assume they put the slot there because they didn't want to interfere with the tapped hole for mounting.
See how the thread is deformed so badly from distorting the thin piece of bronze in that way? All the more reason to make it a little differently/better. I can slot it with something 1/8" or less at the halfway point from the ends and put the set screw in the same orientation, though off center so you can use two mounting screws.
Mine is set up with three holes in line on the top of the cross slide. One is a counterbored clear through hole. The middle is the cone point set screw that spreads the "two halves" (though they're still connected) and the third hole is actually a slightly elongated one, a counterbored slot. To adjust backlash, leave the first one tight, always, then loosen the third (slotted) one. Snug up the middle set screw, tighten the third (slotted) one. There's only perhaps a millimeter of slot length, because the nut would be broken into two pieces if you need more than that.
See how the thread is deformed so badly from distorting the thin piece of bronze in that way? All the more reason to make it a little differently/better. I can slot it with something 1/8" or less at the halfway point from the ends and put the set screw in the same orientation, though off center so you can use two mounting screws.
Mine is set up with three holes in line on the top of the cross slide. One is a counterbored clear through hole. The middle is the cone point set screw that spreads the "two halves" (though they're still connected) and the third hole is actually a slightly elongated one, a counterbored slot. To adjust backlash, leave the first one tight, always, then loosen the third (slotted) one. Snug up the middle set screw, tighten the third (slotted) one. There's only perhaps a millimeter of slot length, because the nut would be broken into two pieces if you need more than that.