A Quick, Accurate Way To 45 Your Corners
If you build boxes at all, eventually you tire of cranking your blade from 90 degrees to 45 degrees and back…I did. So I built this simple jig, and now I can cut all 8 ends of a box accurately in about 5 minutes, AND STILL LEAVE MY TABLE SAW SET AT 90 DEGREES.
Assumption: I am assuming that you have already laid out the board for your sides and have cut all four sides of your box to length. Short side, long side, short side, long side and have cut a dado slot in these boards that will accept the bottom board of your finished box.
(above) The key to efficiency is this jig. It is designed to hold the box side on a 45 degree angle. It has an adjustable stop running vertically in a track, and a clamp to hold it while you run it across the blade. Used properly, your hands will be well out of the way while this is happening.
IT IS IMPERATIVE THAT YOU WEAR EYE PROTECTION WHEN YOU USE THIS JIG. THE SMALL CUT OFF FROM THE DADO GROOVE CAN REALLY FLY AROUND THE SHOP.
(above) To operate the jig, put the bottom dado cut up and clamp the box side in the jig. Feel under the clamped side to see that just a little of the bottom edge of the board extends just beyond the blade-side part of the jig. Now, BRING THE SLIDING STOP DOWN TO CONTACT THE TOP EDGE OF THE CLAMPED SIDE AND LOCK THE STOP. The stop is the white plastic piece with the knob in the sliding track.
Use the clamp lever to be sure the box side is firmly clamped and seated properly in the jig.
Now use the jig to slide the jig and board over the saw blade. KEEP YOUR HANDS WELL INSIDE AND TO THE BACK OF THE JIG. USE THE HANDLE.
(above) Now slide the jig well back on your table saw so the board is well back and out of the way of the blade. To be safe turn off the saw. Release the clamp, spin the side around and put the newly cut edge against the stop.
Then cut the opposite end too.
(above) This shows the two ends cut. IMPORTANT: DON’T MOVE THE STOP. WHILE YOU HAVE THIS SETTING, CUT THE OPPOSING SIDE OF THE BOX…NOW BOTH OPPOSING SIDES WILL BE IDENTICAL IN LENGTH.
If you are making a square box leave the stop in place and cut the next two sides. If it is oblong, reset the stop for the next two sides and cut them.
Jig Building Hints:
(above) This shot shows the bottom of the jig. It runs on a single guide. I prefer UHMW (ultra high molecular weight) plastic for runners. These guides don’t swell or shrink and are self lubricating. If you let the guide extend a bit beyond the back of the jig it makes it easy to align the guide with the table saw slot.
(above) This is not a great shot, but you can see the clamping board is supported by an angle cut 2×6.
While I used a dual clamp modified to hold the clamp in the the jig with one side, and the box side to be cut is clamped on the other side, you could use a simple clamp to hold the box side and screw it securely to fasten it to the jig.
(above) I have found that having the saw-side edge elevated about an inch above the table allows the cut of edges to drop in the center of the blade and the cutoffs are less likely to be thrown by a moving blade. A ZERO CLEARANCE INSERT IS A MUST SO THE SMALL CUT OFFS DON’T GET WEDGED BETWEEN A MOVING BLADE AND THE INSERT.
Recess your clamp so it is even with the angled top of the jig.
Be careful not to let the angled edge of the cut and spun board slip under your stop. If I build another of these, I’ll put a dado and a finger on the stop to prevent the angled side from slipping under the stop.
Design your stop so it stays square to the vertical track.
In practice this jig is quick and easy to use and the build is not really complex. It saves me a ton of time.
-- Big Al in IN