When assembling butt joints, it’s sometimes difficult to hold two workpieces, drill pilot holes, and install screws, all while keeping everything perfectly aligned. To solve this problem, I came up with the right angle clamp you see here. It holds my workpieces at a perfect 90° while I pre-drill holes and drive screws. To use it, Insert your workpieces in the clamp and simply turn the knob to pull the clamp block tight. The openings in the back of the fences allow room for drilling holes and driving screws in a workpiece.
ANGLE CLAMP DETAILS. The clamp consists of two fences. As shown in drawing here the left fence is mitered 45° on one end. Three layers of plywood form the base of the clamp. All three layers are cut to the same dimensions initially. The middle and top layers are then cut in half to form the slots. A slide block fits in the middle slot and has a threaded insert in one end to accept the threaded rod. An insert in the top face of the slide block accepts a hex head bolt that secures the round clamp block. When assembling the clamp, I used a couple of spacers cut from scraps to maintain the spacing of the slots in the top and middle layers. Be sure to wrap the spacers in wax paper to keep them from getting glued in place. Two cleats screwed to the bottom keeps the clamp elevated above the worksurface.
These details give you the information you need for the fences.