Edge-to-edge joints are used to glue several boards into a surface. They commonly come into play for table tops and cabinet parts.
These joints can be plain or reinforced. In both instances, they rely only on glue to hold them together.
A plain butt joint is adequate for most work.
Modern glues are extremely strong and durable. This means that in many cases the joints will be stronger than the wood itself.
One thing to note front and center: all edge-to-edge joints demand a good fit. This means accurate planing. If you try forcing badly-planed boards together with clamps, the stresses will eventually be released. The wood is then liable to split along these points of weakness.
With thin boards like those in door panels, you should increase the glue surface. This can be achieved by reinforcing either side with a tongue set in a groove. Dowel doesn’t do much to add strength but it will help you to align the edges.
The importance of planing cannot be overstated.
Your best bet is machine planing with a jointer. This is by far the simplest method, especially with longer boards. First, plane then mark a face and an edge. Rip the second edge with your table saw. Thickness your boards so you can choose which side looks best. Lay them out on battens, mark the edges then plane the second edge.
You’ll need a great deal of skill to effectively hand plane. If you use a jointing plane, getting a straight edge is not a problem. The hassle comes trying to keep the edge square the length of the board. You don’t want any gaps. These not only look ugly but will become points of weakness.
Practice makes perfect, though. The more you hand plane, the more precise you and confident you will become. Learning and honing new skills is one of the key rewards of woodworking so don’t be put off.
When you are planing, try to apply very slight pressure at the front of your plane at the start of each stroke. At the end of the stroke, press down on the back. You’ll need a sharp iron which is ground and honed very flat. You should set it as close to the front of the opening as you can. Set the cap iron to 1/32 inch for fine cuts and 1/16 inch for rough cuts.
With very thin boards, edge plane while holding them in a shooting board. You can only really do this with shorter lengths. With long, thin boards you’ll need to improvise. Use some plywood on the bench as a base for the plane. Add a batten and stop to hold the thin workpiece.
You can join your boards with rubbed joints or clamped joints. You’ll need a straight edge for rubbed joints. They are restricted to shorter boards up to about 3 feet long. The edges for clamped joints are often planed hollow. This will ensure the ends are kept tightly together.
Hollow joints should only be used if the joints are narrow enough to deflect and fill the gap. With stouter and wider boards in stronger woods, leave the edges straight.
Whether you plane by hand or using a machine, you should plane the edge hollow by hand. Use one or two strokes and a very fine cut. You want to start and end your cut gradually. This allows the edges to come together evenly when clamped.
Machine Planing Edge-to-Edge Joints
When you are edge planing several boards that need to be glued to form a surface, make sure the fence on your jointer is absolutely square.
- Prepare your chosen face and edge
- Rip the second edge
- Thickness the boards
- Match the boards. Lay them out and choose the best pattern. One option is to alternate the grain direction
- Mark the end joints with diagonal lines. Number your joints
- Plane the edges on your jointer. Keep the diagonal lines pointed down toward the bottom of the fence for each edge. By doing this, if your fence is out of square, the edges will compensate for each other and you’ll get a perfect fit
We hope you’ve found this glance at edge-to-edge jointing useful.