Thread: Tearout in Blackwood

Do them on your tablesaw + bandsaw, Rocker. See Bob Smalser's article. Very quick and easy. Not as quick as the jig but more so than the hard way.

SilentC,

I am going to take the easy way out and use biscuit-reinforced mitre joints instead. My Porter-Cable biscuit joiner can do that job very effectively.

Rocker

Blackwood can be a bit of a pig on the planer as well if the knives are not razor sharp and if you don't offer the stock up to the cutterhead on a skew angle. Hand planing the stuff similarly requires some skill in my experience. Pity, as it is a delightful looking timber.

I had a look at the 15 drawer cabinet after posting that. Bob's method is not really suitable anyway for a cabinet with such tall sides because you have to balance the piece on it's end against the mitre gauge to cut the pins. You could do both pins and tails on the bandsaw though.

I'll post a picture soon of this little cabinet I'm making. It has a dovetailed carcass and I'll bet you couldn't tell how the dovetails were made if I didn't tell you

Have fun with your biscuit jointer. I must get one of them one of these days.

Hey Rocker,

How are you routing the dovetails on the Leigh?
When cutting the tails in really fissile material I first use a ¼" or 5/16" spiral to cut the bulk & then a dovetail bit. I've never had tearout with the board sandwitched between scrap. I clamp a waste board in the top clamp that is thicker than the depth of the tails & butt it up against the work piece. If there is room I'll clamp a scrap piece to the front as well.

Through dovetails on my Incra Jig are done in pairs, face to face thus avoiding the tearout problem. Rocker, can you do the same trick on your jig, it might solve the problem.

Major,

You are right; I probably could have lessened the problem by using a straight bit first to get rid of most of the waste; and yes, I should have used a thicker backing board than I did. But I also got massive tearout in the edges of the board when routing the tails, which would be hard to prevent, short of gluing a sacrificial piece to the edge. But I think the biscuit-reinforced mitre joints will work OK.

Termite,

With the Leigh jig, you can't rout both boards simultaneously as you describe for the Incra. But my impression is that the Incra would not have been able to tackle the job at all. My cabinet is 400 mm deep, and 1240 mm high. I think the Incra is more suited to much smaller dovetailing jobs. I had to rig up my Leigh jig on a board resting on two step-ladders to get the needed height.

Rocker

Originally Posted by Rocker

Major,

You are right; I probably could have lessened the problem by using a straight bit first to get rid of most of the waste; and yes, I should have used a thicker backing board than I did. But I also got massive tearout in the edges of the board when routing the tails, which would be hard to prevent, short of gluing a sacrificial piece to the edge. But I think the biscuit-reinforced mitre joints will work OK.

Termite,

With the Leigh jig, you can't rout both boards simultaneously as you describe for the Incra. But my impression is that the Incra would not have been able to tackle the job at all. My cabinet is 400 mm deep, and 1240 mm high. I think the Incra is more suited to much smaller dovetailing jobs. I had to rig up my Leigh jig on a board resting on two step-ladders to get the needed height.

Rocker

Rocker,

You need to climb cut the front of the board CAREFULLY..... this is a lot easier if the tails are fairly large :confused: Just do repeated LIGHT passes until the corners are well defined.
Oh well next time........
Im sure it will look great whatever joinery method you use.

Originally Posted by MajorPanic

Rocker,

You need to climb cut the front of the board CAREFULLY..... this is a lot easier if the tails are fairly large :confused: Just do repeated LIGHT passes until the corners are well defined.
Oh well next time........
Im sure it will look great whatever joinery method you use.

Major,

I am a bit confused here about climb-cutting; surely you do that with half-blind dovetails, not through ones.

Although I am tempted to give the dovetails another go, taking your anti-tearout precautions, I think I will try the mitre joints. Here the main challenge will be the clamping for the glue-up. But a combination of band-clamps and regular clamps should do the trick.

Rocker

Originally Posted by Rocker

Major,

I am a bit confused here about climb-cutting; surely you do that with half-blind dovetails, not through ones.

Although I am tempted to give the dovetails another go, taking your anti-tearout precautions, I think I will try the mitre joints. Here the main challenge will be the clamping for the glue-up. But a combination of band-clamps and regular clamps should do the trick.

Rocker

Rocker,

Climb cutting workes particularly well with fissile material.
It's one of the tricks I was going to teach at Carba-Tec's woodworking course on the Leigh Jig. As I finishrd the lesson plan & the finished item the whole workshop was closed down.