These clamps are designed to allow any wooden sub fence or fixture to be quickly installed and removed if your fence isn't equipped with T-slots. Not only are they convenient, but they also don't protrude into the cutting area in front of the fence like conventional clamps do.
They're a great starting point for an easily removable sub fence assembly using Grip-Tite's Steel Fence Plates: the Steel Faceplate is screwed to a plywood or MDF sub fence, and then one end of the Hole Clamp is slipped into a hole in the sub fence while the other end is tightened over the rip fence or router fence.
Clamps are sold in pairs and work with fences between 2-1/4" and 4-5/8" wide. For for INCRA Table Saw Fences, a wooden block can be attached to the rear of the fence using the T-slots or double-side tape to add thickness and protect the aluminum fence surface.
