Trouble with Dovetails

[Jeff Urich]

I am trying my hand at making my first dovetail joint. I've successfully cut out the tails however I'm having trouble cleaning out the area between the tails. I drilled out most of the area figuring I would clean it up with chisels however I can't seem to get a smooth surface. I'm also getting too much tearing away when I chisel close to the edges. The piece is very soft, cheap pine I got from the local ACE Hardware. I attached pictures so you can see what's happening. Suggestions?
Thanks!

[Robert Rozaieski]

Chop only half way through from either side to prevent chipout. And scribe your baseline with a sharp gauge or knife, not a pencil. The scribe line will help prevent chipout and give you a place to put your chisel for the final paring cut. Forget drilling. It's too slow, especially in pine.

http://farm3.static.flickr.com/2219/2377946160_0cb37dae0e.jpg?v=0
Take a couple chops from the first side and leave the end of the waste in tact to support the waste and keep it from breaking out when you chop from the other side. Then flip the board and chop from the other side to remove trhe remainder of the waste.

http://farm3.static.flickr.com/2211/2377946162_3487a72d68.jpg?v=0
Finally, pare to the scribed baseline and make sure your chisels are sharp enough to shave with. Pine needs to be cut cleanly with a very sharp chisel. Hardwoods are more forgiving of a slightly dull edge but pine only responds well to the sharpest of tools. Any hint of dullness and pine will just chip and tear out because it is so soft.

[Alex Yeilding]

make sure your chisels are sharp enough to shave with. Pine needs to be cut cleanly with a very sharp chisel. Hardwoods are more forgiving of a slightly dull edge but pine only responds well to the sharpest of tools. Any hint of dullness and pine will just chip and tear out because it is so soft.
Jeff, I second this comment. Pine is not a very good wood to learn on. It seems counterintuitive at first that a softer wood would require a sharper chisel. But I'm not sure it is softness so much as the contrast between the summer and winter wood. When your chisel comes upon a heavy, dense, hard winter wood ring, there is very little "backing" to support that wood while you cut it. So if your chisel is not super-sharp, it will just push down on the winter wood, compressing the soft summer wood underneath it, maybe for a few layers, until there is enough resistance to support the top layer while your less-than-perfectly-sharp chisel pushes through. That yields a very ragged cut.

[gary Zimmel]

Jeff

One thing you can do is use a fret saw to cut out as much of the waste as you can. With a little practice you will be able to cut quite close to your line and save yourself alot of chopping with the chisels.

Keep us posted on how the dovetails are turning out.

[Dave Anderson NH]

Robert and Gary have given good advice, particular on the requirement for sharpness. An additonal thing to help would be to make sure your baselines are smoothely cut and not the least bit jagged on both the top and bottom show surfaces. Once you get past the forst cut (chop) on each side of the board it sdoes not matter whether or not the insides of each board are smoothe. What does matter is that they are flat or even easier, slightly concave. Some consider making them concave to be "cheating", but in softwoods undercutting makes life a lot easier.

[David DeCristoforo]

"Some consider making them concave to be "cheating", but in softwoods undercutting makes life a lot easier."

Slightly undercutting the shoulders is not cheating! In fact, it's recommended by most "experienced" makers.....

[Joe Cunningham]

I'm no expert compared to these other guys, but just some words of encouragement--my first dovetails (also in pine) looked similar. I switched to poplar, made sure my chisel was sharp, and my results improved markedly a day later.

Two days later I made a box for my chisels with half-blind dovetails, also with poplar. I think it was within 1/64 of an inch on the diagonal for a rectangular box (roughly 16 x 7). They are not the prettiest joints I've made (future dovetails have improved each time), but considering the abuse they have taken banging around in my jeep for 6 months, I am pretty happy with them.

Sawing is still the hardest part for me. I try to practice a little every day after work. Even something as easy as slicing bread is a chance to practice your technique.

[Floyd Mah]

I've had a little experience with cutting dovetails and I've worked out a technique which is slightly unconventional, but works well. When you are chopping out the tails, handling each tail individually, especially with a chisel can leave a ragged, zig-zag line due to the accuracy of placing your chisel and tilting your chisel. I've found that if you place a straight-edge along the marked line of the tails and precut the wood fibers of the waste all at once, you can establish a clean straight edge. Make sure that you compensate for the bevel of the knife or razor (works better) so that the shoulders are perpendicular to the board. Next you want to waste the wood adjacent to the cut. If you were to place the chisel in the cut, you would bruise the wood and wind up with a dented cut. To avoid this, place the chisel about 1/16" or 3/32" away from the cut, on the waste side. The flat side of the chisel should face toward the cut, the bevel side out. A light tap of the chisel will break the fibers free by tilting the small chip of wood upwards. This will uncover the clean razor edge. After this, waste the remainder of the tail in whatever fashion that you choose (paring, coping saw, bandsaw, etc.). The stubble that remains is pared away with a sharp chisel. The clean razor cut also provides a shelf to rest your chisel on while you are paring. This sounds a bit wordy, but it's basically score a line, tap the chisel a few times, cut the waste and pare. The tails will look professional and you would get the same results in soft or hard wood.

[Mark Singer]

"Some consider making them concave to be "cheating", but in softwoods undercutting makes life a lot easier."

Slightly undercutting the shoulders is not cheating! In fact, it's recommended by most "experienced" makers.....


I agree and undercut a few degrees

[Pedro Reyes]

I think you are doing it right...

What is easier to cut, or I should say, where do you get the cleaner cuts, on a soft tomatoe or a harder onion?

same thing, try poplar and you will see much cleaner cuts.

/p

[John Thompson]

Use a cutting gauge to mark your base-line as a pencil mark will not give you a register to place the chisel tip. And if you can't hold it vertical.. use a guide as mentioned. Using poplar would be a plus over pine as mentioned and be sure you are working with a razon sharp chisel as mentioned.

About everything has been mentioned.. I would suggest writing it on a pad and organizing it on a pad as opposed to trying to remember from just reading. Everything that has been metioned is important and you will learn that.

BTW.. I under-cut just short of the scored line.. take it to the small BS and make relief cuts to the under-cut and then create the final inner wall to the scored line with a very sharp chisel. Works for me.

Sarge..

[Derek Cohen]

Jeff

When sawing tails first, the most important task is to saw square.

When paring/chopping the waste, the most important task is to maintain a straight baseline.

Here are two jigs that can help with the latter:

http://www.inthewoodshop.com/ShopMadeTools/AJigforParingDovetailBaselines.html

http://www.inthewoodshop.com/ShopMadeTools/ANewJigforParingDovetailBaselines.html

Regards from Perth

Derek