I was recommended by the below:
Forrest Woodworker II (40T) $166
Ridge carbide TS21040TK (40T) $129
Freud LM72R010 (24T) $45
Amana 610240 (24T) $90
The Forrest and Ridge blades are general purpose blades, but the Freud and Amana blades are rip cut blades.
I use the forrest woodworker II 40 tooth. You have to make sure that you get it with the special grind though, the standard woodworker II 40 tooth wonít do what you want.
The part number(s) you want to look for are WW10406125 for full kerf and WW10406100 for thin kerf. If you search on those part numbers you will find lots of prices with many of them in the $130 range.
Forrest DOES NOT recommend these blades for general purpose work, just flat bottomed grooves and dados. Many places do not sell this model, so make sure you donít get diverted to a woodworker II with a different part number.
is right. If you want a flat-bottom version of the Forrest Woodworker II blade, you will want to order the "modified" version, not the standard one that most people buy.
I have the thin kerf "modified" version of this blade. I bought it to replace my standard kerf Woodworker II (ATB) when it goes out for sharpening, and to have a flat bottomed blade for very thin box joints. I would have preferred to have a flat-bottomed full kerf blade and a regular ATB thin kerf blade, but oh well.
The full kerf version is here:
The thin kerf version that I have is here, look for the blade with "Modified #6 ATB+R":
Some "flat bottomed" blade configurations still have "bat ears" to reduce tear out. That includes the Forrest blades mentioned above. The alternating top bevel points protrude just above the height of the flat bottom, leaving slight "needle points" in the corners of the cut, which may be slightly visible for box joints, but it should be good enough for most work.
These blades are ATB+R, which stands for "alternating top bevel plus raker". It is the addition of the flat raker tooth that cuts the flat bottom. The standard Woodworker II (and many other brands of combination and general purpose blades) have ATB grinds without the raker. I assume that ATB grinds are superior for through cuts; otherwise manufacturers would be selling ATB+R blades for general purpose use.
With respect, I don't agree with Terry Q's assertion that the modified Woodworker II blade should not be used as a general purpose blade. I bought it mostly for general purpose work, but wanted the flat bottom for box joints too. I have not used it much, but it has worked well as a general purpose blade so far.
Before I bought the Woodworker II Modified (ATB+R) thin kerf blade, I spoke with a technical expert at Forrest about using it for general use. I openly wondered why more people don't buy this blade for general use (plus better box joints!). He enthusiastically agreed with me. He often wonders the same thing. He said that he thinks it might be a better general purpose blade, because the modified (ATB+R) blade is comparable to the ATB version for crosscuts, but much better than the ATB version for rip cuts. He says that the raker tooth reduces the force needed to push the wood through on rip cuts, and they will go faster too.
I recently bought that thin kerf modified Woodworker II ATB+R just before I sent the regular Woodworker II blade for sharpening. I have not had much time to use it yet. I will report back after I gain some more experience with it.
I have a FREUD SD208 dado blade set. Dado blade sets are designed to make flat bottoms, but like many dado blade sets, the SD208 has the "bat ears" that I described above.
I looked at the Freud SD208 blades. The "inside blade" has alternating "left ear" and raker teeth. The "outside blade" has alternating "right ear" and raker teeth. Together they make a kind of ATB+R set. The chippers have two raker teeth each.
Of course, the minimum kerf of most dado blade sets is 1/4 inch. I looked into using a single dado blade to get a thinner kerf for a box joint without buying another blade. It was a good test, but I am not sure I would make regular use of the idea. I would hate to create uneven wear on the inner blade alone, where eventually the two blades will become mismatched. See this thread:
If you scroll down, you will eventually find photos of my tests on scrap wood with single and double dado blades.
Both Forrest and Freud make box joint blade sets with flat bottoms. They use a two blade sandwich (like a minimum dado set). Unlike a dado set, you can swap the blades to get two different kerf sizes.
If it were me, I would choose one of the two general purpose blades, either the Forrest or Ridge. I am pleased with my Forrest blades, but have no experience with the Ridge blade.
I would not recommend buying a rip blade like the Freud or Amana, unless you plan to make a lot of rip cuts.
Personally, I think that using an ATB+R blade for general purpose use is the way to go, despite Terry Q's assertion otherwise. We will have to agree to disagree on that one. I like the idea of using one blade for most cuts, including box joints.
(That said, I met a Freud representative at the woodworking store. He was there to demo his new four-blade router bits, but we had a discussion about the Freud Fusion blade, which is NOT flat bottomed, but I liked the design a lot for through cuts. I may buy one someday.)