Is it a stupid idea to make my own dado blade??

[Duane Bledsoe]

It suddenly occurred to me that I might be able to make up a cheap dado blade from 7 1/4" circular saw blades by alternating teeth alignment so that the blade bodies lay flat next to each other and the teeth overlap in their cut kerfs. It probably would require more blades than would be economical to make a 3/4 dado blade, but for 1/2" or less it might not be that bad. Would it even be safe to do?? Maybe use shims between them so it doesn't require as many?? Sometimes these blades can be bought for around $5 to $8 each here. I could put together a 1/2" dado for probably under $30. But I don't want to lose a finger or get hurt bad in the process. I have no experience with dado blades at all, so I don't know a thing about what I'm talking about doing here. Seems to me that the required amount of blades might be too heavy to turn them fast enough to work also, or could damage my saw. What are your thoughts??

[Rich Engelhardt]

Sometimes these blades can be bought for around $5 to $8 each here. I could put together a 1/2" dado for probably under $30.
IMHO - it's false economy.

There's a few "real" stacked dado sets that run under $50.00.
Harbor Freight sells one for ~ $35. It's on sale now for $27.

There's another one I can't recall right now that often goes on sale for $39. It's very well thought of by a number of forum members.
W/luck someone will chime in with the name and where to get it.

You might also try Sears and see if they have any of the Freud box joint blades left @ the closeout price. I believe I paid around $30. for mine on closeout.

[Neil Brooks]

Hoh-boy.

This is not a case where I'd be re-inventing the wheel.

JMHO. YMMV. Professional driver. Closed course. Etc., etc.....

[Paul Steiner]

I had the harbor freight blade and it has to be better than a bunch of stacked blades.

[HANK METZ]

It might have merit if say, you only wanted to dado for 3/4" plywood shelves. 3 blades @$5 each ($15 total) would give a spaced dado of 3/4"- 1/4" (the blades combined kerf loss) / 2 = both lands @1/4" each, and they wouldn't be too tough to break out. Finish with an old woman's tooth, file, sanding stick or router with bottom cleaning bit and... aw the heck with it, just get the dado set. :)

- Beachside Hank

[scott spencer]

Stupid...no, ill-advised...yes. A self made stack will cut grooves but the bottom is likely to be riddled with ridges. Stacked dado sets have bevel edges on the outside cutters, and flat teeth on the inside chippers that are all very closely matched to give low tearout at the exit of the cut, plus leave a nearly perfectly flat bottom....ain't gonna happen with a bunch of ATB blade stacked together. Stacked dado blades also have proprietary overhand designed specifically to work as a set...individual ATB blades are made to work alone, and have an overhang designed for that. Check Ebay (http://www.ebay.com/sch/i.html?_from=R40&_trksid=p5197.m570.l1313&_nkw=onsrud+dado&_sacat=See-All-Categories) and see if there's any $35 to $51 German made Onsrud stacks left...tough deal to beat.

[Jerrimy Snook]

Dado sets are designed to be stacked together on an arbor. There is no interference between the teeth on each of the blades. The plates or saw bodies are meant to touch not the carbide, the carbide will break if stacked together.

The dado set is also ground so that it will give a relatively flat bottomed cut (Forrest, Amana, Freud etc will be better than HF or Avenger). Dado sets will usually include shims that allow for 0.005" adjustment to dado width.

Another consideration is material to cut. Almost all dados will rip natural wood. Very few dados will leave an acceptable cut in melamine. Of course a zero clearance insert or dado specific sled will help any set.

The cost of sharpening adds up quickly and may exceed the initial purchase price of an inexpensive dado. I wouldn't consider some dados sharp when they are new. Also, every piece should be sharpened with the set otherwise you will have uneven dado cuts.

Jerrimy

[Dustin Lane]

I tried this and considered myself stupid for it. I got a deal on a set of 10 or so 7 1/4" circular saw blades and stacked/alternated the teeth. It works, but it's the sloppiest dado you could hope for. I could get a better cut just taking a full sized 10" 1/8" thick blade and taking several passes. So now, I've wasted a fair amount of money on a bunch of blades I'll likely never use. This could have been put toward a much nicer dado set than the one I actually ended up with. So my advice is just buy a cheap dado set if you're worried that much about cost, much better than paying for a cheap dado set and a stack of 7 1/4" blades.

[Kevin Presutti]

I believe on the bay there are some Onsurud blades, I am sure I remember seeing them there. If you do not find them in a search just look in the guys ebay store, I'm pretty sure he had stacked dadoes.

[Kyle Brooks]

Check out an Oshlun. I have one and it cuts pretty good. Smooth bottom. http://www.amazon.com/Oshlun-SDS-0842-8-Inch-Tooth-Stack/dp/B0012YF25Q/ref=sr_1_2?ie=UTF8&qid=1325259737&sr=8-2

[steven c newman]

I have done this trick a few times. When I needed a DEEP dado, for instance. I used two crosscut blades for the outside, and a couple "rip" blades as chippers. Didn't go out and buy them, they were just sitting around the shop. The other time I needed this trick, my "normal" dado set was out getting sharpened, so a three blade "set" was used. I suppose I could have used the router and a narrow bit, but I like to used the saw for through grooves. I have broken a router bit or two doing those narrow through grooves. Dado set I use is a 6" set from Vermont American. Hey, it works. 217648

[Peter Quinn]

I use some pretty cheap blades in my skill saw for demo and rough work, and for that they are fine. But they aren't the most precise things I've seen. I just can't imagine stacking 5 pieces of junk together and getting any decent results. For everything I usei my dado blade to do I require more precision than I feel possible from a disposable saw blade. Plus my dado can be sharpened as many as 10 times, then retouthed by the factory. With the disposable blades, when they are done, you pay again. So yes, stacking skill saw blades to make dados may not be your best option.

[Van Huskey]

If you want to do it you can. The dados won't be pretty but if you have some blades lying around do it yourself and satisfy yourself. I did it a couple of times back in the old days with non-carbide toothed blades, in the end a wobble dado cuts a cleaner groove.

[glenn bradley]

Scott hit the downsides. Many folks have done this and depending on what you are making (an outhouse for example) it would be OK. All kidding aside, IMHO if you want a cheap way to make a dado, use a router bit.

[steven c newman]

Another point about circ. saw blades: Two blades will NOT make a 1/4" wide groove, you'll need a shim, OR a third blade. BTDT.

[David Lawhorn]

Another vote for the Onsrud set if they are still available on ebay.

IMO very good for the $

[Duane Bledsoe]

OK, I saw a set at Harbor Freight today, and was surprised to learn I can get a dado blade that cheap, so for learning how to use them and to save money in the mean time I'll likely get that set.

But anyway, I'm clueless about the way a dado is supposed to work, other than it leaves a wide cut path when finished. But are there supposed to be spaces in between the blades?? I saw one set that only had 2 blades spaced out the full width of the dado cut, and didn't look like it had anything in between, just two blades only. Then I saw one that only had one regular sized blade and said it was adjustable. From looking at that one it appeared that I'd have to readjust the blade after every pass to eventually get the full width of the cut. If I was going to do that I could just adjust my fence after every pass and keep my standard blade in it instead. Still another one had multiple blades but also had spaces in between them.

I'm interested in a dado blade to cut 3/4" dadoes for shelf and cabinet making mostly. Also for rabbeting with a sacrificial fence and a partially buried blade.

[steven c newman]

OK, the set i use has two "regular" blades. These are used for a 1/4" wide dado, AND as the OUTSIDE blades on anything wider. I can then add a "chipper blade" between the two outer blades. Each of these chipper blades are 1/8" thick, along with (in my set) a 1/16" thick chipper. By adding all the chippers together, with the two regular blades, I can have a width of 1/16" OVER 3/4". I can then bury the set in a fence about 1/16" to make a rabbet of 3/4" wide. I have a picture of that set-up:217701As for how one mounts the chippers, I put each on the arbor, then "spin" the stack a bit. I add another chipper so that it's cutters are 90 degree from the first one. As I add more, I split the difference between chipper, trying to balance things out.

There are some dado blades out there that use just two blades. The disc in the center of the set rotates, causing the blades to tilt away from each other. This causes a wobble that cuts a wider dado/croove. There use to be single blade wobbles out there as well. They made a rounded bottom to the dado's groove.

Clear as mud, right?

[Neil Brooks]

Duane-

HERE's (http://www.newwoodworker.com/hottodado.html) a decent how-to about using dado stacks to cut dados and grooves.

[Duane Bledsoe]

Well I'm glad you said that some wobble because if I had installed one and saw it do that I'd figure it was about to come off and I'd remove it and return it as defective. That's probably how that single blade one from HF works that is supposed to be adjustable.

[Alan Schwabacher]

The HF (and better) stacked dado sets are cheap enough that there is no point in trying a wobble dado blade that will cut significantly less cleanly and safely.