# Incra IBox - did I damage jig by adjusting pins while locking screw was tightened?



## docyoung1983 (Mar 6, 2018)

My success with my Incra IBox seems to be very hit or miss. One minute I'm producing perfect, snug box joints, and the next I'm wasting board after board with joints that are too large, not aligned, etc.

I have read enough articles on this jig to know that a good deal of setup and tweaking may be necessary to produce good joints. I have read Alan's very informative posts with some helpful hints and tidbits from the inventor himself. All that aside, my main question is, if in the past I have accidentally made some significant adjustments with the silver and red knobs WHILE the locking knob is fully tightened, could I have done irreversible damage that makes the jig unreliable and inaccurate? On at least one occasion (and likely several) I have gone through the entire setup process from the kiss calibration through making the actual cuts with the locking knob tightened down the entire time.

The reason I ask is that my jig, as mentioned above, seems to act a little squirrelly on occasion. On my current project I am cutting 1/2" box joints down the entire length of multiple 24" boards. Sometimes the joints remain perfectly spaced the entire way. And then, without making ANY adjustments to the silver or red knobs, when I cut my next board the joints are misaligned and don't fit into the prior-cut board. When I say misaligned, specifically it looks like the first few joints align perfectly, but then the next joint is off by 1/64", the next a little more, the next a little more, etc until by the end the joints are off by a good 1/8". The annoying thing is that, again, no adjustments have been made between this board and the one before it. The errors just seem to start sporadically popping up right in the middle of the cut. I have also noticed that my kerfs initially fit snuggly against the pin plates after initial setup when starting a project, but after a few cuts the kerf starts to fit much more loosely, as if the pin plates have moved closer together.

So, coming back to the original question, might I have ruined my IBox somewhere along the way by failing to loosen the locking screw before making some of my adjustments?


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## therealSteveN (Oct 29, 2016)

To be truthful I don't know if you can strip it out, but my gut says it's well made enough that you probably have done no harm. I have used mine a lot, but it's been very sporadic, so when I have been away from it to remember all the right moves I watch the video below. It starts on the table saw, then goes to the router table, then goes to special functions. Look at it is all I can say. I went from the 3rd use into the 4th with almost a year in between, and had issues like you are having. Went all the way back to the set up, and worked through till I had it ready to use again, and all of my troubles went away. I think you are just missing something.


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## RichT (Oct 14, 2016)

The part of your post that is troubling is that the kerf isn't fitting the same as you move along. The kerf can't change, so it must be the guides. Actually, I should say that the kerf shouldn't change. If it is, you've got bigger problems than the jig.

Contact Incra. They have excellent customer service. If you damaged anything they can tell you and will likely replace it for free.


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## therealSteveN (Oct 29, 2016)

> The part of your post that is troubling is that the kerf isn t fitting the same as you move along. The kerf can t change, so it must be the guides. Actually, I should say that the kerf shouldn t change. If it is, you ve got bigger problems than the jig.
> 
> Contact Incra. They have excellent customer service. If you damaged anything they can tell you and will likely replace it for free.
> 
> - Rich


Rich click on the video I posted. Right around 3:25 they show you how to adjust the kerf width with the pins. Maybe you and I are having one of those semantics things going on? I agree Incra customer service is great, a direct line to Alan is better though. I am pretty sure that just starting anew and doing a complete set up will also fix this.


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## RichT (Oct 14, 2016)

> Rich click on the video I posted. Right around 3:25 they show you how to adjust the kerf width with the pins. Maybe you and I are having one of those semantics things going on? I agree Incra customer service is great, a direct line to Alan is better though. I am pretty sure that just starting anew and doing a complete set up will also fix this.
> 
> - therealSteveN


Hi Steve, I've watched that video. I guess I didn't say it clearly, or misread the OP, but it sounded like the fit of the guides inside the kerf in the board was loosening. My point was that the width of the cut can't change, so the guides must be moving, which would point to a problem with the locking mechanism on the guide fingers (pins).

My point about it being a bigger problem if that cut width is changing was that, assuming he's using a dado setup, it would point to a problem with the saw like runout, worn bearings or something else.

I prefer using my router table with spiral bits, but that's another story.


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## docyoung1983 (Mar 6, 2018)

Thanks for the help so far guys.

I did contact Incra support as you suggested. You are correct - they are very helpful. I haven't had a chance to put some of their recommendations into practice yet, but they echoed your statement that almost certainly the IBOX was not damaged. It's apparently a tough little gizmo.

I am still a little curious about the kerf issue. Rich, you are correct. As shown at 3:25 in the video, I initially set the kerf width as described, but it seems to get looser as the cuts go on. At first, I can feel a moderate amount of resistance as the kerf slips over the pins. But then, as I do more cuts, that resistance disappears and I easily slip the kerfs between the pins with little to no resistance. Either the pins are slipping, or the problem is with the dado/ table saw, or the problem is with the operator (which is the most likely cause). I just bought myself a fancy new pair of calipers, so I'll have to check the kerf widths and box joint widths and see which of the two are not consistent.

Two of the techniques that I received from customer support were:
1) Aim for LIGHT resistance when setting kerf width, as seen at 3:25 in video. I had been adjusting for moderate to heavy resistance (because more is always better!).

2) Keep sideways pressure on the jig when making dado cuts. If there is any slop in the push and pull through over the dado it will potentially cut the kerf too large. This could be the operator error described above.

I used to actually use 2 miter bars to try to eliminate the slop, but due to laziness I stopped and just went back to using the built-in miter bar. I think I may go back to using a miter bar on both sides and see if that makes the operation a little smoother.

I'm going to implement these new techniques and see what happens.


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## therealSteveN (Oct 29, 2016)

Good luck.


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## Putttn (Feb 29, 2012)

I use the Forrest 2blade setup that I got from Incra. Also I clamp the boards being cut as they do in the video. I found I was moving the stock when I didn't clamp them.


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## rwe2156 (May 7, 2014)

I learned if you use a caliper and measure the pin width vs the groove you can dial it in much faster and more accurately.

I usually shoot for about .005" bigger groove.


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## RichT (Oct 14, 2016)

> I use the Forrest 2blade setup that I got from Incra. Also I clamp the boards being cut as they do in the video. I found I was moving the stock when I didn t clamp them.
> 
> - Putttn


I also put a strip of 2-3/4" adhesive backed 220 grit sandpaper along the fence. I aligned it with the top, so there is plenty of bare space below to keep the bit from going through the sandpaper (I use a router, but the same would be true for a saw blade). I had found that even with a clamp, the router bit sometimes move the board, especially with really hard woods. The sandpaper/clamp combo has never failed.


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