I would think that a dull bit and the speed of pulling the router through the cut may have something to do with it.
Tell us more about everything you are doing and using.
(a piece of scrap wood clamped to the end of the board at the entry and exit points will prevent tear-out there).

 

Aren’t you going to cut that back anyway? Or is the tongue exposed through the end? 👎🏻

That amount of tear out can be planed off prior to fitting the BB. There are a few ways to avoid that - a sacrificial block, tape, a climb cut. My preference is keep the piece wide/ripping to width after routing gets you a clean edge.

You need to address is the fuzzy edge across the width of the top. To get a really crisp edge strike a knife line prior to routing. I nice way to do a BB tenon is a tracksaw for the initial cut, hog out the rest with a router.

I suggest you strike another line and redo the cut. Don’t touch it with a shoulder plane!!

 

Good call! I considered doing the initial line or cut with my circ saw and straight edge. I’ll do that on the next one!

 

There are several easy fixes to this .
The first is to use a sharp bit. Straight bits are notorious for doing this so the best recommendation is a spiral bit.
Next simply leave the work piece a little wider than the finished dimension. This allows the tear out to happen beyond the width you need . Take it to the table saw and cut it back to the desires width.
In lieu of that simply attach a sacrificial board to the exit edge of the work. . This will protect the fibers of he work piece and place any tear out in the waste piece. It cam be clamped on, taped on or even temp glued on with CA in a couple of spots.
Hope this helps.
calabrese55

 

You could also clamp a sacrificial board to that side so there's no tearout. I do that on the CNC often and it works just fine.

 

It's going to happen going out the end regardless of what you do. It would reduce the tear out if you would put a board behind it as you push it through the saw. What would have been better is if the board was about 1/8" too wide when you run the cross dado and then run the board across a jointer removing the tear out.

Another issue which you may have is the dado blade is dull. There seems to be more tear out on the face than there should be. It would help when running a dull blade if you could cover the face of the board where the cut is being made with masking tape. Rub it on really hard and it will reduce that kind of tear out.

 

I score a line before I make the pass with the router. It requires foresight, but it prevents the problem from happening. Just use a marking gauge before cutting the rabbet. It is a lot harder after the fact.

 

I don’t do that and have no problems, but I’ve done it so many times

We never score lines..

 

Yes, sharp bit, score a line and use a back board. If not using a back board, then use a backsaw to cut the end edges down to the appropriate depth. Rather than using a back board, I often just cut the edges with a back saw.

Sonny

 

I just ROS..