Sommerfeld's Easy Bore Hinge Boring Jig

The jig I received did manage to cut the holes in the door accurately, but not smoothly,as there is a little wobble and shaking going on, which doesn't affect the accuracy. The adjustable set back cams used are the same size and markings as the ones on the Blum jig although are not accurate as to Millimeters, as they are on the Blum. But I found by putting strips of tape on them I could adjust the set back to any MM distance that I need. I can't speak to how, or even if, the drill bits can be replaced, but assume that by unscrewing them from the top they could be. It is fairly easy to adjust without any other tools or wrenches and clamps snugly to the door without movement, although I have noticed that the the adjustment knobs loosen with use, so you have to periodically check to be sure they are tight. A lot of wood shavings are produced by this jig and they sometimes have a tendency to clog up inside the unit, which requires them to be dug or blown out. I solved this problem by drilling a hole large enough to fit a small vacuum hose to the back of the unit. That solved the problem and pretty much gets 100% of the shavings. This jig is definitely a time saver and a good value even with the few quality control flaws, as it's priced at almost half of what the Blum Co.is asking for their original jig, of which this is an obvious copy. If your a one man cabinet shop like mine and your not doing a lot of doors then this would be a good jig to have, and a step up from the Rockler brand jig !