Sneaking up on a dado.

For years I have done it both ways by accident. I see no difference either way. THAT SAID, I do make the adjustment while the blade is spinning and prefer to adjust the fence away from the spinning blade rather that towards the spinning blade.

"Leon" wrote

Me too. Just wanted to be sure there wasn't some ancient chinese secret I was missing out on.

JP

If I understand you correctly, and because of the built-in backlash in my fence mechanism, I align the initial cut to the outside edge of the blade and bump the fence away from the blade for the second cut, thereby making the cut wider toward the fence side.

That said, the best way I've found to precisely _center_ a groove/dado, is to do the math and set the fence as precisely as possible, then run the piece, flip it end for end, and run it again ... that guarantees a centered groove. I can generally get the width precisely this way with one or two test cuts, and then proceed without having to move the fence again.

Hope I understood you correctly.

"Swingman" stumbled in message

... meant to type "making the cut wider away from the fence".

I'm not sure i quite understand your description but... I make the first pass as near dead center as possible, run the piece thru, reverse it and run thru again. Now I have a perfectly centered groove

- if it needs to to be enlarged it matters not which way the fence is moved as long as you make 2 passes reversing the piece for each pass. The downside is that each movement of fence causes the groove to enlarge by twice the fence movement.

Every time I hear Norm advocate this I want to scream "Yeah it's centered but it's wider, too!" As usual. he never explains how to set up a cut, just how to push the wood through.

So are you mak>That said, the best way I've found to precisely _center_ a groove/dado, is

Easier to do than explain. Set the fence so that the first pass is _slightly_ off center in a piece of scrap the same width as your workpiece. Flip the board around and run it through again. Now tweak the fence setting until the two successive passes cut the desired width. Same with router bit or dado stack.

You obviously need the blade, bit, or dado stack to be narrower than the desired width of your groove ... half, or a rch more than half, works well.

Use this method when you want to precisely center a groove in the width of your workpiece.

It doesn't matter. Cut the dados first and the tenons second. One rarely needs an exact 1/4" dado - just a close approximation. (I'd also comment that Norm's centering of the dado isn't required either as long as the face of each piece is oriented the same when the dados are cut.)

BINGO.

Enlarging the groove wastes less wood than making it smaller. Take an RCH less than half the required, tuck the fence and lock, make a sneak end cut, check what you did, do what you need.

Truth is, I use the board width minus groove method to start setting the fence, making it favor less.

Well, in many cases this sorta does matter. I build lots of cabinet doors and most have a 1/4" plywood panel centered in them. For a good fit, the dado needs to fit the panel snugly but not too tight. After that is accomplished cut the tennons.

As far as centering the dado, that just makes every thing a lot easier. Cutting the tennons is much easier if the dados are centered as you only have to determine the depth once and cut both sides at the same time.

I personally use the regular saw blade to cut the dados. A pass in each direction is all that is needed once the fence has been properly adjusted.

That is the point. Start at the center and adjust the fence until the panel that is going to be used fits in the groove. Then cut the tennons to fit the dado.

That's the thing about bosses, they can do things like that and, if they are so minded, make it stick.

In other words, it probably isn't going to really matter how you or anyone else thinks it should be done..

When I cut a cetnered groove I set the blade around the center of the piece, cut it, turn it around and cut again. Measure the fit and bump the fence away from the blade to adjust. I always go away from the blade just because I am used to it and it is AWAY, not TOWARD the blade which just has to be safer in the long run. If the fence is not flexing and the wood goes through straight, there is no difference in terms of accuracy between bumping to or away from the fence. Of course, if the fence is flexing or the wood is not straight going through the saw, neither method will be accurate, or corect.

Tom Hintz

Sorry, boys, the boss is right. Your cut is always between the fence and the blade. By marching your fence away from the blade, you are leaving an invisible cavity, inside the workpiece, and between fence and blade that could allow the workpiece to float out of the cut; your groove will be imperfect. Also, your fence mechanism, if it includes a tape readout, whatever, is adjusted to the inside of the cut, or blade. Your accuracy in adjusting the cut is read from this perspective.

Nonsense -- it's the fence, not the blade, that guides the wood.

If the workpiece can "float out of the cut" then you're not holding it against the fence properly. And if you don't hold it against the fence properly, you're inviting trouble, *regardless* of which side is doing the cutting.

Note that this is true *only* on right-tilt saws; I don't recall the OP specifying which type of saw he was using.

-- Regards, Doug Miller (alphageek-at-milmac-dot-com)

Get a copy of my NEW AND IMPROVED TrollFilter for NewsProxy/Nfilter by sending email to autoresponder at filterinfo-at-milmac-dot-com You must use your REAL email address to get a response.

When I'm sneaking up on _anything_, I always try to sneak up on the one with the salt on it's tail. *Lots* easier that way.

If you are allowing the wood to "float" anywhere, you won't be woodworking long enough to worry about the fence position anyway. The repeated thuds in your ribs and potentially other more sensitive areas of the male anatomy will have long ago caused you to seek a less violent hobby. Featherboards, or simply paying attention to what you are doing (both hopefully) will produce a dead-on centered dado every time regardless of which way the fence is moved. If your wood is floating, well don't worry about the dado, DUCK!

Tom Hintz

God, I love the wreck... the pissants are thicker than the mosquitoes this year. Let's just forget that I have been working wood longer than either of you has been alive, and have stepped up to the table saw some ten million times... Simple physics and your own common sense, if you have any, should lead you to conclude the proper proceedure...do you hold a pencil with one finger? The fence on one side, the blade on the other...this is a pincer that controls the cut. Stick to your computers, boys; as woodworkers, you are a pair of dumbasses.