Thread: Dado capability?

Originally Posted by chook

I am sure that many people who buy a saw, look to see if the thing will take a dado blade but I wonder why. I have just made cupboard which required 36 dado joints. I did these with a router.

All that was required was 2 pieces of timber glued and screwed together at right angles to make a guide and a half inch straight cutter in a router. Clamp the guide in place and push the router through. That gives about a 12 mm wide trench. To get a 19 mm trench I cut a spacer and put it up against the guide fence to move the router across and made a second pass. By taking fine shavings off the spacer I can adjust the fit of the joint very accurately. The joints are clean and flat- in fact just perfect. (I did find that making a plunge cut first on the exit side of the joint avoided tear out as the router exited the joint.)

This method is easy to set up, easy to position, uses tools I already have and is very cheap. No need to buy a special blade worth $100's of dollars. And as I say the router cutter gives perfectly vertical smooth sides and base to the joint.

So why do people worry about whether or not a saw will take a dado blade? There must be something extra that I have missed. I assume that the saw manufactures include the capability for a reason. But I don't see it.

getting an exact width dado which does not match a straight router bit is not that easy or repeatable. with a dado and shims you can an infinitely variable width dados IN ONE PASS...

you just cannot beat a dado blade and a router is much more of a pain. I know you can make a jig for repeatable cuts on a router but its so much simpler with a table saw. I also think its safer, as I find routers to be top heavy and loud and they throw chips at you very fast, none of this is issue on table saw.

just my 2c

What Pellcorp says however each to their own. You do need a seriously powerful table saw to run a dado stack so this might be out of reach for some. For me, it beats running out to buy the exact size router bit over and over again. The multiple purchases of router bits stacks up against a nice dado set with a modest outlay. One dado stack has an infinte amount of widths you can cut.

Originally Posted by sjt

One dado stack has an infinite amount of width you can cut.

And is easy to raise or lower to the correct height.

Also the use of the TS fence for accurate measurements is fantastic. Try routing dado groves with a router on large boards and you will see the difference, especially if you need to make a second pass to make it a fraction, say .5 of a mm, wider.

But best of all the TS is quiet compared with the banshee noise of the router.


Peter.

Okay then, it seems that the advantages that people identify are
1. Safety. (Routers are top heavy and throw chips everywhere)
Probably just me but I find that I feel safe using a router provided I use the thing properly. Some European countries have banned dodo blades for safety reasons, which seems a bit over the top. But it does indicate that they are not risk free if not used properly. But then neither is a pair of scissors. But I take your point about the mess. The router throws dust and wood chips everywhere. My shed is a mess at the moment and a saw bench and dust extractor would solve that problem.

2. Cost (beats running out buying the exact size router bit over and over again)
But you do not need to! With my simple set up and a 12 mm straight cutter I can cut trenches up to 24 mm in 2 quick passes. With 6 mm cutter can go from 6 mm to 12 mm. All you need do is adjust the width of the spacer. Nearly anybody with a router has at least some type of straight cutter. How many people who have a 12 mm straight cutter which comes with almost all routers, also have a dado blade?

3. Setup accuracy (It is easy to raise and lower to the correct height)
No difference on a router. Most routers have a knob which which infinitely accurately raise or lower the cutter. This will be at least as accurate as raising or lowering the blade on a table saw. Also it is easy to adjust the width by less than 0.5 mm if you want. I can widen or narrow the trench by the thickness of a piece of paper or less by widening or narrowing the width of the spacer. As for repeatability all I can go on is the fact that every joint (all 36 of them) fit perfectly.

4. The noise! No doubt about it the noise (and the dust are the two real advantages of a saw over a router)

That said, as soon as I have upgraded

I think both have their place, and dados cross cut in long bookshelf uprights can be a little precarious on the table saw, so a router and adjustable jig
http://thewoodwhisperer.com/exact-width-dado-jig/

Would be a good choice, but for dados along the length of a board - actually correctly called grooves I think a TS wins )