A Guide to Cutting Finger Joints
Looking to show off your artistry as a woodworker? Mastering the craft of finger joint woodwork is an excellent way to do it. Finger joint woodworking is a simple, beautiful method of creating interlocking joints to connect wood.
Finger joinery is a relatively straightforward process. Yet, it is easy to make mistakes when you are just starting.
This guide will take you through the process of how to cut finger joints using a simple jig you can make yourself.
Types of Finger Joints
Before getting started, you will need to decide which type of finger joint is best suited to the project at hand.
Most often, a woodworker will use finger joints when joining two pieces of wood, such as baseboards. You might also see finger joints in floorboards and door frames.
Finger joints often get confused with box joints. You would use a box joint to connect the corners of a box or drawer. You’ll also see box joints on old-fashioned coffee grinders.
You can tell the difference between finger and box joints because finger joints are more delicate and narrow than box joints. However, there is disagreement about the use of the terms among woodworking professionals.
The three types of finger joints are the square finger joint, the stepped finger joint, and the slanted cut finger joint.
Square Finger Joint
The square finger joint is one of the most common finger joints used by woodworkers. It is comprised of different wood stocks joined end to end.
The trick with square finger joints is that the maximum strength of the joint is equal to the strength of the interlocking fingers. With that in mind, consider that the fingers contain half the strength of their joining boards.
Stepped Finger Joint
The stepped finger joint involves stacking multiple different sizes of saw blades before cutting. With a strong enough glue, the stepped finger joint increases the strength of its fingers to two-thirds the strength of the wood.
Slanted Cut Finger Joint
Making a slanted cut finger joint requires a bit of trigonometry. You will need to set your blade tilt to a predetermined angle.
Slanted cut finger joints can be tricky to set up and require precise calculations to work correctly.
Finger Joint Woodwork: Getting Started
Once you’ve determined what kind of finger cuts you’ll be making, it’s time to set up your workspace. All experienced woodworkers know the importance of preparing their woodworking environment before starting a project.
Not an experienced woodworker? Check out this essential guide to woodworking for beginners. You don’t need to be an expert woodworker to create quality finger joints.
To get started, clear your workspace of any obstacles or debris. You should also make sure your worktable or workbench is sturdy and level.
Gather your tools and organize them so you know where they are when you need them. This will streamline the process.
Required Hand Tools
You will need the following tools for finger joint woodwork:
- Dovetail saw
- Coping saw
- Chisels and a mallet
- Small try square
- Bora Clamps
- Table Saw
- Dado Stack
It is important to use tools that have been taken care of properly. Rusting or damaged tools can cause mistakes and risks to safety.
Choosing the Right Blade
It is important to choose the blade that best suits your project. For most finger joint woodworking, you will use a combo blade.
Avoid using combo blades with Alternate Top Bevel teeth. If you use ATB teeth, your joint will not be flat on top, or square.
The best blades to use are ripping blades and blades with flat top teeth (FT blades).
How to Make a Finger Joint Jig
While it is possible to cut finger joints by hand, it is much more efficient to use power tools.
A sliding fence jig combined with a table saw can cut the time it takes to make finger joints in half. You could also use a sliding fence jig with a portable router.
Make the Fences
When making a sliding fence jig, you will first need to make a front and rear fence. A fence is usually a piece of flat plywood or hardwood used to secure or guide the piece of wood you are cutting.
Mount the rear fence to the miter gauge using screws. Later you will attach the front fence using shank holes.
You can drill the shank holes now, but do not attach the front fence just yet. Making the fence holes slightly oversized will enable better flexibility and tweaking to make the cuts fit properly.
Set Up the Cut and Key
First, select and install the dado blade set that matches the width of the pins you’ll use for your project. Once you have installed the dado blade, set the height of the blade to hit slightly underneath the thickness of your workpiece.
Hold the front fence in place and make a single cut through the fence. The fence should not be screwed in yet.
The front fence is the part of the jig that holds the hardwood key. To make the hardwood key, use calipers to measure the cut you made in the front fence. Then cut a small piece of hardwood to that dimension for your key.
The hardwood key should fit snugly in the fence. You should not force the key to fit, nor should it be difficult to remove from the fence.
You’ll want to make sure the hardwood key is long enough that you can trim a portion of it to use as a spacer.
Slide the jig up to meet the dado blade. Place the spacer so that it fits between the indexing key and the external teeth of the dado blade. Once the fence is in the correct position, you can screw it into the rear fence.
The hardwood key should be offset from the blade at the precise width of the cut. This will control the spacing of the pins. The front fence also supports the piece of wood you are cutting to prevent the saw from tearing the wood.
The sliding fence jig is simple enough to make that you would do best to make a new one for each different type of cut.
How to Cut Finger Joints
Now that you’ve constructed your jig, it’s time to start cutting finger joints. When you make finger joints, precision and patience are key. Go slow and practice first so you don’t make mistakes on the wood pieces that matter.
Make Practice Cuts
Take a piece of test wood and practice cutting your notches into it. The test wood should be the same width and thickness as the wood you will use for your project.
Place the edge of the test wood against the hardwood key and cut the first notch. Place the slot you just cut over the key to make the next cut. Continue in this manner until you’ve made all of the notches for that piece.
Take another piece of test wood and place it against the original test piece. You can use the first pin of the original test piece as a spacer. Make your cuts on the second piece of test wood.
When you finish your practice cuts, check the fit to make sure the joints match.
Fine Tune the Fit
If the joint is too loose, move the key a little further away from the blade. If the joint is too tight, move the key closer to the blade.
If the pins are too short, it means your blade is too low. Adjust the blade by raising it slightly. If the pins are too long and protruding, lower the blade a little bit as a remedy.
Cut the Joints
When you’re confident with the fit of your practice joints it is time to start cutting the wood for your project. This wood is often referred to as “the workpiece.”
You should always hold your workpiece snug against the fence and flat against the table. This will ensure a clean and even cut each time. For better accuracy, you can clamp the workpiece to the fence.
Mark your workpieces so you know you are always starting on the same size. Then go ahead and start making your cuts.
It’s a good idea to pause and check that each set of matching pieces fit together properly. Sometimes the jig may move a bit while you’re cutting. It is easy enough to set it back in place if you check it every so often.
Finding the Right Tools for Finger Joint Woodwork
The keys to quality finger joint woodwork include using a jig, practicing your cuts, and taking the time to pause and check your work as you go.
Using good quality woodworking tools and expert guidance will ensure the success of any woodworking project. Woodworking Plans has the tools, woodworking tips, and plans to make your woodworking dreams a reality.
They are an excellent resource for beginners and expert woodworkers alike. Check out the many resources on their website today.