Are there any best practices when using dado blades or stack?

Question

I recently got an 8" dado set for my table saw, and was a little nervous about using it without the normal safety equipment I usually have in place (primarily a riving knife), especially since they've been deemed "dangerous" enough to be banned in Europe. I want to approach my use of the set with a thorough understanding of the dangers involved. Are there general guidelines of what to do/not do with a dado set installed?

For example:

• Can I cut dadoes with the work piece against the fence, or should I strictly use a miter gauge or crosscut sled?
• Obviously using both the fence and miter gauge at the same time would still be a kickback risk.
• Are through cuts a definite no-no with dado stacks? If I need to make one quick one, should I just go through the hassle of switching out the dado stack, reinstalling my regular blade and safety equipment?

So far, I've made a zero-clearance insert to replace my standard insert so there isn't a gaping hole in my saw table around the blade.

Answer 1

1. Can I cut dadoes with the work piece against the fence, or should I strictly use a miter gauge or crosscut sled?

It depends on the nature of the cut. A dado is technically a slot cut across the grain (a crosscut), so in that sense, yes, you would typically use a miter gauge or sled. A groove is a slot cut with the grain (like a rip cut). Regardless of whether you are cutting a dado or groove, if the edge parallel to the fence and blade is significantly longer than the edge perpendicular to the blade, it often makes more sense to use the fence.

2. Obviously using both the fence and miter gauge at the same time would still be a kickback risk.

If you are not making a through cut, there is no offcut to be pinched between the blade and fence and kicked back. Many woodworkers and woodworking publications do not consider cutting a dado or rabbet to provide a significantly increased kickback risk with the workpiece against the fence, although you should not make a cut you are not comfortable making.

3. Are through cuts a definite no-no with dado stacks? If I need to make one quick one, should I just go through the hassle of switching out the dado stack, reinstalling my regular blade and safety equipment?

You can make through cuts with a dado stack, but you must keep in mind that you will waste more wood and will have a more limited depth of cut. You also cannot use a stock riving knife, so you could potentially have an increased chance of kickback over using a normal blade along with a riving knife. If you do make a through cut, definitely ensure that your workpiece is not in contact with both the miter gauge (or sled) and fence as you make the cut.

Answer 2

Here's my best practices taken from various online videos and my own experience. I've cut dadoes mostly for kitchen cabinets, fences or drawers. I have an under-powered (1.5HP) 10" contractor table saw and I use 6" blades for my dadoes. (It's actually the 6" version of your Oshlun set.)

Accessories

• My fence
• A pair of featherboards
• A miter gauge, push block or pushstick
• Another pushstick, scrap piece of wood, etc...

Steps

1. Setup the dadoes (width & height)
2. Remove my blade guard and splitter or riving knife from my saw.
3. Setup my fence to the right position.
4. Install the featherboards (if possible)
   • One featherboard at the start of the cut. (Halfway before the blades)
   • Another featherboard at the end of the cut. (Halfway after the blades)
5. Do the cut
   • First hand pushes the stock with the miter gauge, push block or a push stick.
   • Second hand uses a push stick or scrap piece of wood to apply pressure on top of cutting area. (Ideally, if you have a small piece to cut, you could use another featherboard.)

Reasoning

I used to do dadoes without featherboards until I had a piece fly to the side in a circular motion. I probably failed to apply enough side pressure and downward pressure, so my blades lifted the piece and it flew off to the side. To correct the lack of side pressure, I use the featherboards and to correct the lack of downward pressure, I use a scrap piece or a push stick above the cut. I never had an issue since. The downward pressure also ensure a constant dado depth.

That way, I make sure my hands are one foot away from the blades at any moment.