Figuring Out Finger Joints

For me, finger joints have always been the nerdy, square cousin to the dovetail.

Finger joints are immensely strong when glued properly. But they are usually used by beginning woodworkers in places where a dovetail would be more appropriate, such as on a piece of 18th-century casework.

Add to that the fact that finger joints are tricky or dangerous to make on wide boards (without a commercial jig) plus the fact that gluing them with yellow glue is stressful, and it’s a wonder that anyone uses them at all.

And so we decided to tackle finger joints for the Summer 2008 issue of Woodworking Magazine, which will be shipping to subscribers next month. It took us a few months to really pin them down (pun intended), but I think we nailed it (and no, cut nails are not involved).

Here’s a small taste of some of the problems of the joint we solved after three months of testing in our shop:

Appearance: Finger joints are a product of the machine age. Using them in styles before circa 1900 is just wrong to the eye. So consider the joint for more contemporary pieces only.

Cutting them Accurately: Right now there are basically two different ways to cut the joint: A shop-made jig for the table saw for narrow boards, and using a router jig that costs several hundred dollars for wide boards. We set out to develop a simple and safe shop-made jig that could handle both wide and narrow boards. Senior Editor Robert W. Lang had a stroke of genius on this and solved the problem forever (in my opinion).

Gluing Them Easily: You can assemble small boxes with finger joints fairly easily when using yellow glue. But at a certain point, you hit the wall because the glue sets up before you can close all the joints. So the solution would seem to be a slow-setting glue. Well, that’s one way to go about it. But we found an easier and faster way that is super-strong (see the photo of Managing Editor Megan Fitzpatrick’s boot on a sample joint). In the end, it took an anvil to bust up our sample joints.

Also in the Summer 2008 Issue
The finger joint is just one of the major themes running through the issue. Here are some of the other stories you can look for in the coming issue:

Building a Better Chest: Most woodworkers build chests using the most convoluted and fussy assembly imaginable. After reviewing hundreds of historical models, we settle on a method for building a chest that looks more complex at first glance, but actually saves an immense amount of shop time, requires less fussing around and allows more design flexibility.

Crackle Finishing: Many woodworkers who try a crackle finish have inconsistent results. Sometimes it works; sometimes it doesn’t. And predicting how much it’s going to crackle is almost impossible. Senior Editor Glen D. Huey cracks the code of crackle finish and finds out that the easiest and most predictable way to do it is also the simplest.

Trimming End Grain: When you have to cut back some end grain so it’s flush with some face grain, it’s always an opportunity to mess up the project. We show you two (actually three) methods for doing it right every time with a block plane, sander and pencil eraser.

And one more thing about the Summer 2008 issue: This issue is going to be mailed out to subscribers in a protective plastic bag, which will reduce the chances that the postal service will mangle it. If the plastic bag works for you, let us know so we can encourage our manufacturing division to continue using it.

And if you’re not a subscriber, you can easily remedy that here.

– Christopher Schwarz