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I'm thinking about building this box joint jig so I can make my joints with a single blade (rather than having to pull out my dado set). The problem is that I've got one of them fancy Freud blades that has angled teeth (adjacent teeth are pointed in a different direction). It makes great, clean, quiet cuts, but for non-through cuts, it leaves a little ridge.

I know they make tablesaw blades that don't have the angle on their teeth, but I can't find identify where it's listed online whether it's angled or not. Is there a generic name or description for this type of blade?

  • 60 teeth, or 60 teeth per inch? – Daniel B. Apr 29 '15 at 18:52
  • Good catch, @DanielB. How do you know that link doesn't have angled teeth? – dfife Apr 29 '15 at 19:06
  • That particular blade is a triple chip grind (TCG), so it has a mix of "trapezoidal" teeth and flat teeth. It should produce a flat-bottomed cut, unless some of the trapezoidal teeth protrude a little bit farther than the purely flat teeth. – Doresoom Apr 29 '15 at 19:10
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    Oh dear, it's not, I missed the next line in the descrition. I read flat-top tooth but it's followed by a trapezoidal tooth, so that link may be bad. You'll wind up with a flat bottom but two (slight) grooves on either side of the cut. Basically that blade scores the outer edge before doing chip removal between edges. – Daniel B. Apr 29 '15 at 22:05
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You want to pay attention to the type of tooth grind, which describes how the individual teeth are shaped. Vermont American has a good resource for types of grinds. Any grind combination with at least one flat tooth should give you a flat-bottomed cut.

So good candidates would be:

  • Flat Top Grind (often used for ripping)
  • Triple Chip Grind (for hard, abrasive materials)
  • Multipurpose Carbide Tip (ripping, crosscutting)
  • Tri-Grind (general combination grind)

Your best bet is likely a Flat Top Grind, since there are no angled teeth that may protrude above the height of the flat teeth. Many ripping blades are FTG, so just check the description prior to buying.

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    I like rockler.com/how-to/blades-101, myself. Lots of good info in condensed form. – Daniel B. Apr 29 '15 at 22:12
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    From that link, I think a combination tooth might be good too; less tearout and a faster cut, cleared by the final flat tooth at the end of the group. For Freud at least, they show the silhouette of the teeth next to the tooth count. – Daniel B. Apr 29 '15 at 22:16
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Let's talk teeth! There are more types of grinds, but I feel these are the applicable ones for your question:

Flat top (FT/FTB)
An FT or FTB blade is one which has flat teeth that you're looking for.
enter image description here
Alternate Top Bevel (ATB)
An Alternate Top Bevel (It will be marked ATB on the blade) is one which has alternating beveled teeth, like the one you mentioned.
enter image description here

Combination/"all purpose"
There are also combination or "all-purpose" blades which have "groups" of teeth, a set of ATB teeth, followed by one flat top tooth.
enter image description here

Branding You're likely to see an FT blade marketed as a rip blade and an ATB marketed as a cross cut blade. The blades will also probably be marked wit the cut, though you can also just look at them and see.

So which one?
The problem you're likely ton encounter is that FT blades are typically meant for ripping, which means you're going to have a smaller number of teeth (they're meant to take big bites), where an ATB blades are for cross cuts, so they are likely to have the larger number of teeth you're looking for.

Combination blades have a large number of teeth, and that finishing flat tooth may get you the flat bottom you're looking for. I think this is probably what you'll want, if the Forrest blade Lee mentioned doesn't do it for you (Forum posts and reviews seem to indicate it's good, but it is pricey).

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    An easy (and free!) way to deal with the low tooth count on a typical FTG blade is to reduce the feed rate. If you have 20 teeth on the blade but wish you had 40, feed at half the rate to get the same number of teeth over the course of the cut. Don't feed too slowly though -- you don't want too much heat building up. For the same reason, consider using a blade lube like Bostik BladeCote. – Caleb Apr 30 '15 at 2:54
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Forrest sells a blade which is totally flat. If you have an old saw blade that needs resharpening, most sharpening companies can regrind your blade when they sharpen it to make it a flat top grind.

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    This is the blade I use on my saw, and I can confirm that is makes a nice flat cut. It is a tri-grind style blade. – Ukko Apr 29 '15 at 21:02
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If you have a stacked dado set, you can use one of the outside blades from that set with your jig. Stacked dado blades are flat ground so that they make flat-bottomed dados.

  • That's what I've been doing, but that requires switching the cartridge for my sawstop. That's why I mentioned I wanted a 10'' blade. – dfife Apr 30 '15 at 19:06
  • @dfife I see that now, but it was edited out of your question (probably to avoid having it closed as a shopping question). As the other answers say, you want a blade described as FTG for "flat top ground," and these are easy to find on sites like Amazon. – Caleb Apr 30 '15 at 19:19
  • My stacked dado set has beveled teeth – Steven Jul 30 '15 at 16:49
  • @Steven The outside blades often have beveled teeth to reduce tearout, mixed with flat top teeth to make the flat bottom. The inside blades should have all flat top teeth. If the inside blades on your set are the type that are sort of oblong instead of round and have just one or two teeth, that's probably not going to work (I wouldn't use them). But if you've got a high quality stacked set where the inside blades are round and have a number of teeth, they should work fine. – Caleb Jul 30 '15 at 17:11
  • Thanks @Caleb; it's my first dado set and I just figured the 2-teeth chippers were the norm. – Steven Jul 30 '15 at 17:41

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