6" dado blades WITHOUT bat wings?

[Phil Thien]

I am looking for a decent (not too expensive, please) dado set in 6" size that DOES NOT leave bat wings. Anyone have any suggestions?

[Buck Williams]

I have the Freud SD208 and get a good square flat bottomed cut with it. This is an 8" Dado, usually sells for about $95, Freud also makes the SD206 - a 6" dado cutter. Looks like $85 or less currently on-line. I run the 8" on a 1.5 hp contractor saw and notice no lag in power, there seems to be some conventional wisdom that an 8" blade is too much for a 1.5 hp motor, like I said not something I've had a problem with. There were a few instances when the extra cutting depth came in handy. The Freud is a nicely packaged, all of the cutters stack on top of each other in a plastic blade guard, and there are plenty of shims to accomodate various thicknesses.

[Cyrus Brewster 7]

+1 on the 8" Freud set. I also have a contractor saw and have never noticed any loss of power.

[Larry Fox]

This might be one of those "you get what you pay for" type of things. I understand that most of the dado sets out there leave them to varying degrees. I have a Forrest set and the ones they leave are VERY slight.

[glenn bradley]

If you check the reviews I believe you will find Larry to be correct. Although (as usual) it is easy to pay more for no better a set, a decent set starts at a certain tier. More teeth = better result. More carbide = more money. I went with the SD508 (there's an SD506 in 6") and have been very happy with the result. For dados that will show and must fit like fine furniture, I use a router.

[Phil Thien]

Well, I had the Forrest and it did bat wings.

I want something with no bat wings at all.

Or are they bat ears? I don't want anything bat.

[Ray Newman]

You can eliminate the "bat wings" by taking the complete set (chippers and blades) to a good sharpening service and have all the teeth ground to the same diameter. If sharpened properly, the blade and chippers will cut a flat bottom.

I did that on my old steel and a carbide dado blade set. Both sets now cut a flat bottom.

The only "drawback" is that when you need to have the set re-sharpened, you must have all the chippers and blades done so as to maintain the same cutting diameter.

If you still have the Forrest, give them a call about sharpening the blades and chippers.

[Peter Quinn]

All the dado sets are made with ATB outer blades so they can operate in a variety of materials both with the grain and cross grain. The ATB is going to leave the "bat's wings" , I've never seen a stacked dado that didn't. My forrest set and the one at work are pretty subtle, as are the Freud super dados, but if subtle is too much for your purpose you could look at a solid dado blade. That limits you to a single size for a specific task, but it should get rid of those pesky wings. I think the box joint cutter sets everyone seems to be selling now are also a flat bottom set up. I suppose you could have a dado stack ground for true flat bottom cuts like a rip blade, or maybe a triple chip with a flat bottom racker to keep things square? Most commercial dados are trying to get a very square bottom but also not tear out veneer in plywood, so playing around with the grind might improve the flatness but reduce the sets ability to make other cuts. Infinity also makes a set that might work for you.



http://www.infinitytools.com/Flat-Bo...products/1509/

[scott spencer]

All the stacked dado sets that I know of have bat ears to some degree, because all use top beveled teeth on the outside cutters to reduce tearout. In order for the beveled teeth to have any effect, they must protrude slightly above the teeth of the inside chippers, which in turn causes the slight grooves along the edge of the cut. Some of the better sets stagger some flat top rakers between the beveled teeth to reduce the effects of the bat ears, but they don't eliminate them. Any sets that you find (or have ground) to use all flat top teeth on the outside cutters will be more prone to tearout.

[Adam Slutsky]

I have been using this 6" dado set for a few years now and I think it is a good compromise between quality and price. As expressed by others, it may not leave a perfect cut but it is pretty darn good and I have been pleased with the results.

[Phil Thien]

All the stacked dado sets that I know of have bat ears to some degree, because all use top beveled teeth on the outside cutters to reduce tearout. In order for the beveled teeth to have any effect, they must protrude slightly above the teeth of the inside chippers, which in turn causes the slight grooves along the edge of the cut. Some of the better sets stagger some flat top rakers between the beveled teeth to reduce the effects of the bat ears, but they don't eliminate them. Any sets that you find (or have ground) to use all flat top teeth on the outside cutters will be more prone to tearout.

I was hoping you'd respond. There was a review of dado blades in one of the magazines in the last couple years (I think) where they had pics of the grooves and some of them didn't have bat wings/ears. And I think the magazine even added that as a column ("Dado set leaves bat wings: Y/N").

Anyone remember that article?

[scott spencer]

A lot of manufacturers and users claim "perfectly flat bottom dados", but if top beveled teeth are used on the outside cutters, the claims are in error. For practical purposes some of the grooves are pretty darn small and make next to no difference, but realistically they do exist. I'd be interested in reading the article.

From Forrest's website:


Examples of a cut from the Oshlun set:


Example of a cut from the DW/Delta 7670 set (the bat ears are tiny, but they exist):



There are some specialty box joint cutters, and single blade groove cutters that have flat top grinds...most of those are intended to cut with the grain, which inherently leaves less tearout than across the grain cuts. Some of those claim no (or low) tearout even on crosscuts...the only way I can think of to accomplish that is by using a steep negative hook, and even then I'm not certain how effective it'd be.

[Rod Sheridan]

I have the FS Tools 53DL06 dado set, nice cut............Rod

[Adam Slutsky]

August 1991 FWW had a very good article on dado blades. Even though it's 20 years old, there is still some good info. there.

[Scott Hildenbrand]

Ok.. Just for the sake of me understanding what the big deal is... What's the big deal about the bat ears? The only time I could see it as an issue is exposed dados, which I don't think I would ever do in a furniture grade piece anyway. In that event, I'd do a stop dado instead.

Just wondering..