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Forum topic by Jerry posted 03-15-2015 01:37 AM 1651 views 0 times favorited 45 replies Add to Favorites Watch
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Jerry

1762 posts in 1107 days


03-15-2015 01:37 AM

Topic tags/keywords: question

I was divided about where to post this, but ultimately since I’m wondering if this is safe, this is where it wound up.

After looking at multi – hundred dollar dado sets, I had to ask myself, “Self, what really is the difference between a bunch of saw blades mounted on the same arbor and an “official” dado stack? It seems to me that if you had a bunch of high quality blades, all the same type and could mount them with the teeth not touching each other, that it would work just like a dado set.

So my question is, is this a viable idea, or is it a deadly accident waiting to happen?

All input is appreciated.

-- There are good ships and there are wood ships, the ships that sail the sea, but the best ships are friendships and may they always be. http://geraldlhunsucker.com/


45 replies so far

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Rayne

470 posts in 999 days


#1 posted 03-15-2015 01:46 AM

It should work, but only if your saw has the power to spin the blades of that size at those speeds safely. There’s a reason DADO stacks tend to be smaller than that your saw is capable of for a single blade due to this. Maybe a stack of 7-1/4” blades from a circular saw and teeth not touching might be possible, although I still don’t how flat of a dado you’ll get since the teeth are not pointing in their respective directions.

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Jerry

1762 posts in 1107 days


#2 posted 03-15-2015 01:52 AM



It should work, but only if your saw has the power to spin the blades of that size at those speeds safely. There s a reason DADO stacks tend to be smaller than that your saw is capable of for a single blade due to this. Maybe a stack of 7-1/4” blades from a circular saw and teeth not touching might be possible, although I still don t how flat of a dado you ll get since the teeth are not pointing in their respective directions.

- Rayne

Thanks Rayne, that is very good intelligence. I had not even considered the size – weight issue.

-- There are good ships and there are wood ships, the ships that sail the sea, but the best ships are friendships and may they always be. http://geraldlhunsucker.com/

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Mike Throckmorton

124 posts in 1124 days


#3 posted 03-15-2015 02:00 AM

I would think if you had say 4 fully toothed 10” blades shoulder to shoulder on your TS arbor and all those side by side teeth engaged a board at once you’d have a heck of an instantaneous load applied.

The typical dado set has those widely spaced tooth chipbreakers which reduces the load a lot.

Could stop your saw motor dead or hurl the board.

-- You are never complete, you just draw a line where done is and stop at that line.

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beamrider

24 posts in 2449 days


#4 posted 03-15-2015 02:16 AM

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jumbojack

1667 posts in 2083 days


#5 posted 03-15-2015 02:21 AM

I’ve stacked two together with no ill effects. I cut quite a few 1/4” dados and my stack needs to be shimmed to get 1/4” leaving some ridges. So when I need 1/4” for short jobs ill use my 10” stack. Can’t say for more than two, give it a try, go slow, maybe a shallow cut the first pass just to see. Let us know how you make out.

-- Made in America, with American made tools....Shopsmith

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Ghidrah

667 posts in 681 days


#6 posted 03-15-2015 02:36 AM

There’d be a heck of a lot more torque on the arbor with the added weight, chippers are maybe 1/4 the weight

-- I meant to do that!

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Robsshop

899 posts in 2434 days


#7 posted 03-15-2015 02:50 AM

Long time since we’ve talked Jer(lol) I am no expert on this matter and I am sure there will be those on here that will give a more in depth response, but I feel that this approach will have many obstacles to over come. The Dado set I use is a typical stacked dado set consisting of two outer blades with standard teeth and several chipper blades that widen the kerfs width in 1/8” increments. The first issue I see as a potential problem is the shear mass of several full blades when cutting the larger widths. 1/4” dados are achieved with the two outer blades but I don’t think I would want to be around the TS with 4 or 5 blades spinning that fast ! The next issue I see has to do with the teeth spacing in which the the dado set has built in voids on the outer blades. This is so that the chipper blades can be spaced evenly and with out any of the teeth contacting each other. It may be possible to do this with 2or3 blades but I cant see it working with more than that. There are probably some other issues that others will point out, but I would do a lot of research before jumping in! I know you have a level head on your shoulders Jerry and safety first is always the best practice. Be careful my Friend, I so enjoy our exchanges and let’s keep it that way(LOL)

-- Rob,Gaithersburg,MD,One mans trash is another mans wood shop treasure ! ;-)

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MrUnix

4202 posts in 1658 days


#8 posted 03-15-2015 03:00 AM

I’ve used Matthias’s method (linked above) with great success.. cheap 7.25” circular saw blades with shims. Not a problem.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

View knotscott's profile

knotscott

7207 posts in 2835 days


#9 posted 03-15-2015 03:34 AM

It’ll work. I’ve done it with three 10” 24T FTG blades for a really deep groove. Most 7-1/4” blades are ATB grind so it’ll leave a rippled bottom. That might be ok, but don’t expect it to perform like a good stacked dado set.

One of the more significant differences is that a stacked dado set has two outside cutters with top beveled teeth, each of which is dedicated to one side. Those beveled teeth protrude slightly above the inside cutters to reduce tear out on cross grain cuts.

A stack of ATB blades will leave multiple ridges from a series of v-shapes like this:

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

View bandit571's profile

bandit571

14527 posts in 2143 days


#10 posted 03-15-2015 03:46 AM

Used to do this on my old Craftsman 113. Outer two blades have as many teeth as one can get on a circular saw blade, the inner one(s) were as few teeth as a rip blade could be. A paper shim between them helps, as well.

-- A Planer? I'M the planer, this is what I use

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pintodeluxe

4852 posts in 2272 days


#11 posted 03-15-2015 04:29 AM

Try a Freud Diablo stacked dado set. They can be had for around $80 on Amazon. I cut thousands of tenons and mile of dados before it finally needed to be resharpened this year.
One big advantage of a traditional stacked dado set is the shims. You can make a perfect groove for even sizes, or undersized plywood.
Plus a 3/4” stack of 10” blades would require at least 6 blades, so the traditional dado stack may even be cheaper.
Good luck with it.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View rick1955's profile

rick1955

258 posts in 890 days


#12 posted 03-15-2015 11:39 AM

I would call it inexperienced. You don’t need a 10” dado for one. You haven’t done the research or read enough in the magazines.
http://www.amazon.com/Oshlun-SDS-0842-8-Inch-Tooth-Stack/dp/B0012YF25Q
The Oshlun SDS-0843 is highly rated. It compares to dado sets at $200.

-- Working smarter with less tools is a true crafts person...

View ShipWreck's profile

ShipWreck

557 posts in 3212 days


#13 posted 03-15-2015 11:47 AM



I was divided about where to post this, but ultimately since I m wondering if this is safe, this is where it wound up.

After looking at multi – hundred dollar dado sets, I had to ask myself, “Self, what really is the difference between a bunch of saw blades mounted on the same arbor and an “official” dado stack? It seems to me that if you had a bunch of high quality blades, all the same type and could mount them with the teeth not touching each other, that it would work just like a dado set.

So my question is, is this a viable idea, or is it a deadly accident waiting to happen?

All input is appreciated.

- Jerry

I love creative thinkers like yourself. But in this case, I think a 1 1/2 HP saw might be too weak. The diameter of the blades would bog the saw motor down…....IMHO. But there are smarter folks on here than me that could chime in.

View rwe2156's profile

rwe2156

2187 posts in 940 days


#14 posted 03-15-2015 12:29 PM

Multi-hundreds for a dado set? You’re either looking at 10” or Forrests.

As the poster said, a Freud 8” dado set is 90 bucks – about the cost of 2 blades. I’ve used one for years, in fact, I’ve had it sharpened twice and its still a decent cutter. A CMT is around 120. I’m a big fan of the orange blades (lots of carbide).

Just for the sake of argument, lets look at it:

You’re making a 3/4” dado. For the sake of argument, lets say the blades cost $50.

1. How many blades would you need to stack up for 1 pass, 6 (2 xcut + 4 rip)? 5 blades = $250

2. 3 blades and 2 passes? 2 blades = $100.

3. 1 blade and 6 passes? This is what we’re trying to avoid.

Solution: save your time and money and get a Freud 8” set.
(Remember you will have to make a bunch of insert blanks for diff widths).

I’ve learned its best not to try to cut the depths perfect right off the saw
Just as a suggestion, here’s how I do dadoes/rabbets:

1. Knife the two edges (deeply).
2. Cut dado set slightly above depth.
3. Make an initial scoring cut about 1/16” deep.
4. Finish to final depth with a hand router plane.
5. If its a through dado, always leave the board a little wide to plane off any edge tear out.

I think this technique will give you a superior dado or rabbet because:

1. The depth will be perfectly uniform.
2. If the dado goes to the edge there will be no saw marks.

-- Everything is a prototype thats why its one of a kind!!

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JeffP

573 posts in 851 days


#15 posted 03-15-2015 01:17 PM

FWIW, it is not the weight, but only the torque increase caused by the larger radius of the blades (compared to typical dado set) that is of any consequence here.

The increased weight of stacked blades will make the saw spin up slower, but once full speed is achieved the added mass of stacked blades would be a GOOD thing, not bad. (think flywheel) Once spinning at full speed, it does NOT take more power to spin a 100 pound blade stack than a normal blade. (well, ok, 100 pounds might very slightly increase the friction on the bearings, but you know what I mean)

I have heard that some people with a Saw Stop who are too cheap/lazy to purchase the additional brake cartridge required for a dado set have used the stacked 10” blade setup. You loose a significant amount of the Saw Stop safety advantage while doing this (since you are asking the brake to stop more mass and it can’t do it as quickly). I suppose it could also damage the saw if it did detect a finger and attempt to brake…due again to the increased mass/inertia.

For the sake of clarity here…I have heard of such people. This euphemistically hypothetical individual…would not be me. (I use my router table instead)

For the un-initiated, the reason a Saw Stop user might stoop to this unsanctioned method is that the SS electronics “looks” for a blade within some tolerance distance of the brake, and will refuse to turn on if it doesn’t find it. A normal sized dado set is too small for it to detect it…so you have to use a different size cartridge in the SS with a dado set.

-- Last week I finally got my $*i# together. Unfortunately, it was in my shop, so I will probably never find it again.

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