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Discussion Starter · #1 ·
Hi,

I have a Dewalt router (the one that comes with the three bases). I'm new to woodworking and have been using the plunge attachment to route some dados for the cabinet I am building.

I set the plunge depth to 1/4" by using the Kreg spacer bars. I confirmed the depth by plunging, locking the router and used a digital bit depth gauge which read .251.

After I made the dado, I used the digital bit depth thingy and it read .200. When I use the Kreg bar I can see that there is a slight gap between the bottom of the bar and the bottom of the dado.

I should add that I am checking the bit height by setting the bottom of the digital depth thingy on the top of the bit blade. Meaning, I am touching it to the very top of the blade. But even so, I am using the 1/4" Kreg bar between the plunge mechanism and the depth stop (sorry, I don't know if I am using the the right terminology).

Am I doing something wrong? Is the amount I am off in normal tolerances?

Thanks!

N
 

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I do a measurement and also a test cut in a piece of scrap.

The cut rules. :yes:

Set the bit height by whatever means, then make a test cut. I then use a fractional dial caliper to measure the depth of the cut not a digital.

http://www.grizzly.com/products/Fractional-Dial-Caliper/D3208

Tweak the bit height setting if needed and do another test cut to confirm.

A digital measuring device is accurate only if used in decimal or metric display. If you use with a fractional display, the actual measurement is rounded to the closest 1/64in similar to this chart.

http://www.seoconsultants.com/charts/inches-decimal/
 

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bzguy
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Not sure what your digital thingy is but .05" is almost 1/16th, unacceptable for precision work.
I have gotten by without a lot of "thingies", confirm it with a normal tape measure by "burning an inch".
Hold the one inch mark on the the surface and check the depth, almost a 16th off will show up pretty obviously, more than the 1/32" lines on your tape.
 

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Discussion Starter · #4 ·
Thanks for the replies. The digital gauge I used was this: http://www.rockler.com/igaging-digital-3-in-1-multi-gauge

It displays in decimal, so rounding to the fraction is not the issue.

I understand what you are saying re testing on a piece of scrap. That makes sense. I guess what I am wondering is why there is such a discrepancy. I had always thought I could use these: Kreg PRS3400 Precision Router Table Set Up Bars, Set of 7 - Amazon.com

to set my bit height and it should come out pretty darn close to the thickness of the Kreg measuring bar. Now it sounds like I'm going to have to make a test cut, try to tweak from .200 to .250, test again, repeat etc. Sounds like a whole lot of work every time I want to use the router.

Is this what you guys have to do? Or do you find that when you set the depth you pretty much end up with the depth you expect. Wondering if there is something I am doing wrong somewhere that is resulting in a difference.

Thanks.
 

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where's my table saw?
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this should help

 

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Even with measuring (I use the tape on the 1" mark) I still do test cuts. Never hurts to be sure.
I have never regretted making a test cut on a piece of scrap.

I have regretted not making a test cut when I was in a hurry and foolishly assumed the measurement was exact. :thumbdown:
 

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I have never regretted making a test cut on a piece of scrap.

I have regretted not making a test cut when I was in a hurry and foolishly assumed the measurement was exact. :thumbdown:
Definately. It takes less time to do a test than to have to redo a bunch of parts. Nevermind the material you're gonna waste...
 

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John
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Hi,

I have a Dewalt router (the one that comes with the three bases). I'm new to woodworking and have been using the plunge attachment to route some dados for the cabinet I am building.

I set the plunge depth to 1/4" by using the Kreg spacer bars. I confirmed the depth by plunging, locking the router and used a digital bit depth gauge which read .251.

After I made the dado, I used the digital bit depth thingy and it read .200. When I use the Kreg bar I can see that there is a slight gap between the bottom of the bar and the bottom of the dado.

I should add that I am checking the bit height by setting the bottom of the digital depth thingy on the top of the bit blade. Meaning, I am touching it to the very top of the blade. But even so, I am using the 1/4" Kreg bar between the plunge mechanism and the depth stop (sorry, I don't know if I am using the the right terminology).

Am I doing something wrong? Is the amount I am off in normal tolerances?

Thanks!

N
I'm a little confused as to just exactly how you are setting the depth. That is immaterial though. I use the method demonstrated in woodnthings video and it always works. Just use your Kreg spacer bar between the depth stop and the turret.:smile:
 

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Discussion Starter · #11 ·
Hi,

Thanks for all the comments and suggestions. I do make a test cut, but what I'm getting at is to @jschaben's comment:

"I'm a little confused as to just exactly how you are setting the depth. That is immaterial though. I use the method demonstrated in woodnthings video and it always works. Just use your Kreg spacer bar between the depth stop and the turret."

...that's exactly what I do. And as far as I can tell, that should result in a cut that is pretty darn close to the depth of the Kreg spacer bar (in this case 1/4" or .250). But, I ended up with a cut that was .200.

So, I'm trying to understand why that might be. Don't think the stock is cupped at all, looks pretty straight to me.

Thanks.
 
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