Incra I-box

[Dan Kopack]

Just recently purchased the Incra I-box jig. After setting up the jig and cutting the first joint(call it the front board), I then began the second joint ( call this the side board). After completing the second cut, and then checking the "fit" of the two joints, I learned that each successive joint on the second board had moved incrementally. Meaning they continued to move throughout the cut. Making sure the thumb screw on the top of the jig was tight(locks the settings in place)I began cutting another piece of stock. This time checking the adjustment after each cut, the adjustment moved!! What am I doing wrong?? What have I forgotten to do?? Anyone else experience this issue or am I just an idiot and should give up woodworking and take up bridge?

Thanks.

[Charles Lent]

Do you have a dial or digital caliper? You will need to measure the pin and space (notch) widths. They should be the same within a few thousandths of an inch. If not the same, check the width of the fingers in the jig. My guess is that you didn't get the fingers to "just touch" the blade in your jig calibration steps.

Don't give up woodworking. I get as much enjoyment solving little problems like this as I do in making projects. The I-Box jig works very well, once you understand it and get it set up correctly. Attached are a couple of photos of some of my recent box joints in Baltic Birch plywood using my I-Box jig, my Unisaw, and a Freud SBOX8 blade set.



Charley

[Jason Lester]

On a box joint, when they progressively get worse and worse, your setting is usually slightly off. The reason it keeps getting worse is you're compounding the error on each successive cut.

[David Eisenhauer]

Stupid questions
Is your box stock all sized correctly for width, square and parrallel sides?
Did you mark the faces and orient the edges correctly when setting up for the matching cuts on the second board to the first cuts board?

[Jared Sankovich]

As stated your adjustment is off.

These are 12.5" tall drawers with 1/4 pin size. Cut 4 at a time
396417
396416
396418

[Dan Kopack]

Mine is dial, thank for the suggestions.

[Dan Kopack]

Makes sense, I’ll keep practicing

[Dan Kopack]

Thank you, mine were 13.5”

[Dan Kopack]

Yes, did all that, thanks

[Dan Kopack]

Yes, did all that, thanks, more practice needed.

[Charles Lent]

Begin with a more careful re-calibration.

Charley

[Dave Cav]

I don't have any pictures to show you, but mine worked perfectly right out of the box. Keep trying and pay attention to the settings and the instructions, maybe watch the videos on Youtube; you'll figure it out.

[Dan Kopack]

Will do, the you tube videos make it look soooo easy

[Dan Kopack]

Should I make the fitting of the pins in the cut tighter?

[Butch Spears]

Dan, as others have said ! The IBox is Great. Pay closer attention to where they tell you about pin touching the blade. I got scrap and set mine up the first time. But I had to play with it, to really understand what they were saying. not directions fault,but my wanting to be in a hurry. Start from set up and start over. You will be pleased that you did. Good Luck

[Von Bickley]

I will say that I did not get perfect joints on my first attempt. I had to play with it and make several adjustments, but I finally got it adjusted where I could get perfect joints. Stick with it...

[Alan Schaffter]

Dan, I don't work for INCRA, but am the father of the I-BOX. I have seen a few problems like you are having since it hit the market over six years ago (has it been that long?!?!). Here are my suggestions. You didn't say if you were using it on a tablesaw or router table, the procedures are the same you just need to be more careful during calibration on a router table.

First, make sure you have assembled it correctly, and that your miter bar is adjusted properly- proper width and no slop in the table slot and perpendicular to the I-BOX fence.

The biggest mistakes people make are they are careless, do not calibrate or set-on correctly, and they force the adjustments. Remember, the I-BOX uses a dual pitch lead screw and just like any screw or machine bolt, once you have "tightened" it you can always tighten it more- turn it farther- 1/4, 1/2 or more rotations past where it was initial snug. Doing that on the I-BOX affects not only initial calibration but also setup for your router bits and blades. Don't do it! You must adjust both gently and carefully! Box joints must be accurate to within +/- .004" to fit properly!

When you calibrate, adjust the pin plates so they just touch, with no light between them, BUT DO NOT turn the red knob any farther, which while physically possible, will mess up your calibration and might even damage the leadscrew and/or followers. Practice this a few times to get the feel.

During calibration, when you adjust the position of the mated pin plates (using the silver knob), make sure they just "kiss" the tip of the carbide cutters. DO NOT allow the pin plates to deflect the blade. To verify the "kiss," gently rotate the blade back and forth- the carbide tip should just barely scrape the pin plate. You can not use a warped dado, a "wobble" dado, or any dado whose outer blades (trimmers) are shimmed improperly, not flat and do not follow a perfect circular path when they rotate. Practice this a few times to get the feel.

Remember, calibration and finger size setup are two totally different operations.

When you set the pin plate (finger size) spacing to the groove made by your dado blade, again you must be gentle and pay attention. Turn the red knob until the plates touch the sidewalls of the dado- there should be just the slightest amount of friction when you slip the stock on and off the pin plates. If the fit is too loose or too tight the joint will not be right. Again, remember the tolerances required for finger joints.

Remember, when using either red or silver knob, the mechanism MUST be unlocked- you must start again if you forgot. Also remember, whenever you turn the silver knob during calibration or when fine tuniing the fit of a joint you must keep the red knob from turning while allowing the mechanism to move left and right. There are thousands of I-BOXes out there working fine, just be patient and careful. You will quickly get to the point where calibration and setup are second nature and you'll be cranking out the boxes.