# The Problem With The Incra Miter Gauge



## Jerry Bowen (Jun 25, 2011)

The Incra Miter Gauge is an outstanding tool and I have been impressed with it until now. The problem that I am having with it is not necessarily the fault of the gauge. The problem that I am referring to is that in order to get the most out of it is that in the end the user, in my case, myself, has to do the final calibration and if that is not done perfectly, the real accuracy of the gauge is lost. I have mine calibrated so that all of my 45 degree cuts are as good as I would ever like them to be, but when cutting six workpieces at 30 degrees, the result is off just enough to tell me that either the gauge is not perfectly calibrated, or the gauge is not as accurate as I have been led to believe that it is.

The slight error that I am talking about, is admitedly slight, but it does exist and I want a miter gauge that is dead on, this one might be, but the issue of calibration rests with me and it's giving fits.

Jerry
Colorado City, TX


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## Mike (Nov 22, 2004)

Jerry, you can use a plastic drafting triangle to set your angle and then calibrate your miter gauge so it is exactly on. Once the calibration is set you should have no future problems.


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## WayneMahler (May 17, 2012)

I'll agree with Mike. Once it is set up correctly it should be on. I double check my miter gauge when making cuts. I have set ups for 45* 30* and 22.5* i use. Mine is not an Incra but hoping to buy one soon. I have found that cutting a setup jigs is the best way to go. Mine has not left down yet.


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## Jerry Bowen (Jun 25, 2011)

This is addressed back to Mike as well as any one else that says that their gauge is dead on. Are you saying that if your miter gauge is set correctly that when you cut the six parts at 30 degrees that if the cuts are made with the the parts firmly again the fence that e all six joints are absolutely tight? Then with that calibration your 45 degree cuts are also dead on.

Right now, when I make the cuts, I am gettin an error on .003" when the parts are four inches in length. That is close, but not dead on. When I make 45 degree cuts I can decern no error at all.

Jerry


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## cagenuts (May 8, 2010)

Jerry, watch this video.

How do you know the initial cuts are indeed 45 degrees? Even the Wixey digital gauges have a margin of error. So again, it's best to follow the linked video, make the appropriate adjustments until you get it correct. It then doesn't matter what any gauge is telling you.


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## Jerry Bowen (Jun 25, 2011)

Hilton,
The way I conclude that my cuts are at 45 degrees is when I cut a picture frame and clamp it up with a clamping strap and the joints fit perfectly with no gaps at all, to me this dead on at 45 degrees, am I missing something. As to the Wixley digital gauge, it's a cute gadget, but a far cry from a precison instrument, and was a waste of money in regard to being used for any precision work.

Jerry


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## Mike (Nov 22, 2004)

Jerry, you are worried about .003" when working with wood? Breath on it and it will change to be perfect. Once the gauge is calibrated by using a triangle it will be dead on in all positions. You should check out the Betterley Una-Gauge here: Betterley Industries


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## Jerry Bowen (Jun 25, 2011)

Hey Mike,
Maybe you have found the problem, maybe I'm to picky, but to me .003 inch gap that you can see light through is, or has been, dut to my ingnorance, unexceptable. I just order an Osborne miter gauge and want see how it works compares to my Incra gauge, if I still have the same error with the Osborne gauge, I will know than my expectations are just greater than what is possible with these high end miter gauges.

Jerry


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## Jerry Bowen (Jun 25, 2011)

Getting back to Hilton's suggestion to watch the video about tuning the miter gauge. I had watched that video before posting my remarks about the Incra Gauge. After makeing the twelve 30 degree cuts on six workpieces and seeing that the miter gauge was not spot on, the error was extremely small but did exist. The question then becomes, how does one get that last thousandth of an inch or so error out of the setting. Yes, you sure know that error exists, but how can you adjust it out without using some trial an error method. That's the rub as far as I can see. I cannot detect any error with my machinist square wieh checking 90 deree cuts, but error does exist when doing the drill as shown in the video, but thanks for the suggestion anyway.

Jerry


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## Jerry Bowen (Jun 25, 2011)

Mike,
Can you tell me a little more about the triangle that you are referring to, I am not familiar with one and would like to know more about one as to it's accuracy, it's rigidacy etc. If you read this, I hope that you will respond, also, is there a way to contact you directly through this forum or some other way, you seem to stay on top of the posts that I am making and you also seem to be pretty savvy about woodworking.

Jerry


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## Jerry Bowen (Jun 25, 2011)

Mike,
I ordered two drafting triangles, a 45/90 and a 30/60, maybe this will help with the calibration.

Jerry


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## harrysin (Jan 15, 2007)

Jerry Bowen said:


> Mike,
> I ordered two drafting triangles, a 45/90 and a 30/60, maybe this will help with the calibration.
> 
> Jerry


Jerry, if you want picture frames as accurate as the professionals make then perhaps you should use the same method, a guillotine which stamps out a perfect triangle, no errors what-so-ever.


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## Dmeadows (Jun 28, 2011)

Accuracy of the miter gauge is only ONE of several things that can result in thousands of an inch error when cutting miters! The work piece has a tendency to want to move when cut at an angle, the blade may flex that much, any saw dust between the gauge and the work piece will cause an error, etc, etc. Also, if you flip the board over to make cuts, consistent board thickness becomes an issue. If the blade is not perfectly 90 deg to the table will cause errors. The more sides(cuts) to a frame, the more the errors add up. Any and all of these will contribute to the total error! 

Accurate work was done for many, many years before Incra, Osborne, and Wixey tools were available. Very accurate tools can make the job easier, but it is STILL a matter of technique and attention to detail that makes accurate cuts. I really doubt it is an issue with the Incra being inaccurate!


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## KenBee (Jan 1, 2011)

Perfection when associated with woodworking is a misnomer and should never, ever be attempted at the risk of major disappointments. My take on perfection when working with wood is attaining a 1/32nd +/- tolerance in most instances. Wood moves and the configuration is subject to change at any given time, even during a cut.


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## CharleyL (Feb 28, 2009)

You might consider this. It's a sled for cutting picture frames. The beauty of it is that if it's not perfectly set to cut at 45 deg, by cutting first piece on the left side of the sled and then the mating piece on the right side of the sled, any errors from setup will be cancelled out and the two pieces will fit together at a perfect 90 degrees.

http://www.amazon.com/Rockler-45-Degree-Miter-Sled/dp/B001DSXS8O

I have also seen a miter gauge with a side fence that's a perfect 90 to the face, but couldn't find a link to it. For picture frames and similar you turn the miter gauge to about 45 deg and then cut your pieces in a similar manner to the above sled, one cut on the face fence and the mating cut on the side fence. The cuts aren't at a perfect 45 deg but they complement each other to produce a perfect 90 degree joint when placed together.


Charley


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## Dmeadows (Jun 28, 2011)

CharleyL said:


> You might consider this. It's a sled for cutting picture frames. The beauty of it is that if it's not perfectly set to cut at 45 deg, by cutting first piece on the left side of the sled and then the mating piece on the right side of the sled, any errors from setup will be cancelled out and the two pieces will fit together at a perfect 90 degrees.
> 
> http://www.amazon.com/Rockler-45-Degree-Miter-Sled/dp/B001DSXS8O
> 
> ...


That will work for 45 deg cuts, not so much(at all) for 30 deg!

I like this...

Single Dubby Cutoff Fixture

I have a very old version, but it works well!


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## roofner (Aug 1, 2010)

Jerry are you cutting the pieces with stop blocks so all pieces are the same and using the settings for all pieces?


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