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I am using the Rockler dovetail jig on some 3/4" walnut. I have been successful one time with this jig but I always manage to have issues cutting the tails. I am using the bits that come with the jig and maybe that is the issue. I am sandwiching my project piece between two 1/4 pieces of plywood cut to the same dimensions as the project piece.

I have already figured out how to cut the pins successfully. The method I use is cutting in small increments as well as climb cutting. I do not have to sandwich the project piece between two pieces of plywood for this cut.

Any suggestions would be nice. Scrapping some good hardwood is getting expensive.

Finally getting a chance to upload some pics here. I went back out and finally tried again. I was trying to use climb cuts to do this, and it started out alright, but by the time i got to the end it started tearing out again.

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    I'm not certain it's necessary but pictures showing where the tearout occurs, and how bad it is, might be helpful here. – Graphus May 17 '16 at 8:25
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    What speed are you running the bit at? – Steven May 17 '16 at 17:33
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    It is mostly tearing out when coming back UP out? I always take the router down on the corners first, regardless direction, and then clean out the bottom. – Joshua May 18 '16 at 5:05
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    I'm no expert on routing but to me this screams sharpen your router bit. I don't know if it's just a temporary glitch but only the final pic is showing up currently and in that the problem isn't tearout (fibres torn away from the face of wood) but folded-over fibres that weren't shorn neatly by the cutting edges. Now this is far preferable to tearout since there's no wood missing, so you can file off or pare away the 'lip' and you'll have clean tails. Other than that one issue, this looks like a very neat routing job. – Graphus Aug 24 '16 at 6:49
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    Silly question: What direction is the grain running? From the photo, it looks like the grain is running across the tails, when it should be running along the length. For a long-grain to long-grain connection, you probably want a different kind of joint. – Mr. Kevin Aug 25 '16 at 1:13
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In addition to using scrap to support the wood during a cut, as Bert said, grain direction can affect tear out. In your photograph above, the cuts are being made on end grain, which greatly increases the odds of tear out, unless you can change the direction of the cut in some way to avoid pulling at the grain as you leave the cut. I don't have any experience with routers, so I'm not sure what your options would be if you have to make an end-grain cut.

However, in this specific case, the grain should be running along the length of the dovetails, instead of across the dovetails. (Dovetails are subjected mostly to tension forces, and wood does not have very good tensile strength across the grain.) Putting the dovetails on the correct sides of the board should reduce or eliminate the tear out.

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Generally speaking, if you put a piece of scrap lumber on the outside of the piece you are cutting with the router before you put it in the jig clamp (I'm guessing it is a clamp system as I do not own such a jig) it will stop tear out due to slight variations in the router bit path due to controlling it by hand. What this does is instead of the tear out occurring on the good piece of stock, it happens on the scrap instead.

Tear out only happens on unsupported fibers when you try cutting them. And 1/4 inch plywood will not stop it on your good stock due to how plywood is constructed. It happens no matter if you use a muscle powered or an electric powered tool. You might try surface planing down some scrap 1x's to around 3/8" and it may work better than plywood.

If you want an easy primer on this, get on YouTube and look up Paul Sellar's woodworking channel. He does everything the old fashioned way but he is a wonderful teacher about explaining why he does things the way he does.

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  • Do you have any of his videos in mind to compliment this answer? – Matt Jun 8 '16 at 19:29
  • youtube.com/watch?v=OCYjoj6cfno – Bert Jun 10 '16 at 10:58
  • This is the video on how to make a dovetail joint by Paul Sellers youtube.com/watch?v=OCYjoj6cfno This is a video about making a dovetail template youtube.com/watch?v=hYpWldwGHFY In fact, on his wood working channel, Paul Sellers covers a lot of different questions you will encounter when working with wood no matter if you are a beginner or a seasoned veteran. What I really like about him is that he demonstrates that becoming an expert woodworker doesn't have to be hard or expensive. He also gives instructions on making and caring for your tools. – Bert Jun 10 '16 at 11:09
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The obvious answer to this:

It is tearing out as I bring the router back out of the jig.

would be: "Well, don't do that then". Yeah, very funny, I know.

But there is some truth in that.

After reading the first three lines, I was going to suggest a climb cut, but then realized that you are already doing that (at first, I was assuming a climb-cut spiral bit being used).

The situation "When I bring the router back out of the jig" shouldn't happen at all. The intent of a climb cut is to reduce or eliminate tearout because the cutting blade always pushes into the wood rather than pulling it outward and tearing fibers. There is however no way of not pulling outward when exiting unless you can change the router's rotational sense and the direction the bit's blades face mid-operation (which you obviously can't).

If possible, use a spiral router bit because those are less obnoxious to the wood as the cut is more "continuously flowing" rather than "hammering into the wood". A conventional, straight bit like the one shown on the website will generally produce a larger amount of tearout no matter what you do.

You can try doing just over half of every pin (climb cut, clockwise), exit where you entered (without touching). Then turn the work piece -- preferrably, the entire jig with the work piece still in it -- around. Now do the other half.

That way, you have climb cuts entering on either side, and no exits. Is the only method where you can guarantee that tearout is at a minimum.

(Alternatively one could use the router upside down for the second half, but I advise against that for obvious reasons.)

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  • Are you suggesting a spiral dovetail bit? The dovetail bit is what is causing the tear out. – fizch Jun 23 '16 at 19:02
  • Ooooh.... well, that rules out the "spiral bit" part. There is no such thing as a spiral dovetail bit --- to my knowledge. If that exists, it's a total rarity. But the rest still applies. – Damon Jun 23 '16 at 23:01
  • I did look into it. I found some spiral dovetail bits but they are $200 - $250. I think I will pass on that. – fizch Jun 24 '16 at 14:44

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