Originally Posted by
Charles Lent
Justin,
Now that you have an I-Box jig, here are several tips -
1 - The miter bar must be adjusted so that it slides easily in the miter slot, but with no side play.
2- Get a piece of 1/4" MDF. I buy the Handy Panels from Home Depot in 2' X 4' size, because I never need much of it at a time and storage is difficult in my small
shop. Cut it up to match the dimensions of the sacrificial strip that comes with your I-Box jig. Then make a drill press set-up to drill one hole. Then flip the piece
and drill the adjacent hole. Now flip the piece end for end and repeat the process to drill the two holes in the other end. Then remove your positioning jig and
countersink all 4 holes from the shiny side. A 2' X 4' piece of 1/4" MDF will cost you about $6, but will let you make several years worth of sacrificial strips for
your I-Box jig. Incra sells them at about 3/$10, so in an hour fun and easy shop time you will have saved about $50. You don't need a new sacrificial piece for
every cut. Just slide it left and right to use an un cut area for the next cut. You can invert the sacrificial piece and use the top edge too, so probably 30 box joint
setups for each sacrificial strip.
3 - When adjusting your I-Box jig, always remember to unlock the adjustments with the top knob and lock the adjustment when complete. The red and silver knobs
at the end of the I-Box jig are for calibration and setup. If you make an adjustment without unlocking with the top knob, you may damage internal parts.
4 - The initial calibration requires that you adjust the jig so that the finger just touches (kisses) the cutter or blade. This is critical. It should touch, but not deflect.
5 - After you have set up your I-Box, make a test cut before committing your work pieces to be certain that they are what you want.
6 - Once you are happy with the test cut, move the sacrificial strip to a fresh position and load your work piece(s). Since the front and back of a box are the same size,
My Cutting Method -
I label both of the box front and back work pieces with an "A" on the side that will be facing out when the box is complete. I also always begin with them against the pin for the first cut, and do the same with the other end of the "A" pieces, so both ends start with a pin. For me, they get positioned against, but touching and not deflecting the fingers in the jig. After each cut, the work is moved and the previous cut is now placed over the fingers in the jig. IT should fit with no play, but should not be tight. Also both ends must receive the box joint cuts beginning at the top edge with a pin. Don't cut one end beginning with a pin and the other top end beginning with a notch. Keep them the same on both ends. Do the same with the "B" labeled pieces, but both ends beginning with a notch at the top.
Use a clamp to hold the work in position and down against the jig. If you are cutting two or more at the same time, use additional clamps or double sided tape to keep them moving together without any movement in relation to each other.
When beginning the cuts of the "box sides", I label them "B" on their outside face and always begin the cut by using the first pin and notch of an "A" piece as the spacer to get the "B" pieces started correctly. Just insert an "A" piece first notch on the guides with the first pin to the left. Then insert your first "B" piece against the edge of the "A" piece. Then make the first "B" piece cut. You don't need to use the "A" piece again after this first cut.
So the first cut of the "B" pieces will be a notch and not a pin.
I have found that my I-Box jig holds it's calibration so well that I can place it in it's storage box, and if cutting the same box joint again, just take it out of the box, change to the same saw blade, set the correct blade depth of cut, then move the sacrificial piece in the jig to a fresh position, and begin cutting perfect box joints again.
If your miter gauge does not fit the miter slot of your saw or router table and there is side play, your box joints will not be accurate, varying by the amount of side play of your miter gauge bar and slot.
Charley