Miter Joints (Mitre Joints), How To Make Them Strong, Woodworking Joinery

A miter joint (mitre in British English ), sometimes shortened to miter, is a joint made by beveling each of two parts to be joined, usually at a 45° angle, to form a corner, usually a 90° angle. There are 9 positive miter stops at 15, 22 ½, 30 and 45 degrees on both the left and right side. Before cutting the miter, use a combination square to check that the 45° miter line still meets the shoulder of the tenon at the inside edge. There’s a solution for that: First, trim off the inside edge of the too-short part. I’ll confess, I didn’t want to give the best miter saw overall ranking to a Dewalt miter saw.

If we align the miter gauge to the miter slot, the cut will be square to the miter gauge fence and the edge of the wood resting against it. This is because the miter gauge moves the wood along a path controlled only by the miter slot. To use the blade as the reference we would have to alter the position of the miter slot itself, not the fence on the miter gauge that slides within it. Even then, the miter gauge would have to be squared to the slot or the cuts will not be square. Clamp short trim pieces to the saw table with C-clamps to avoid placing your hand in the path of the blade.

The most advanced miter saw not only makes these fancy compound cuts, but the actual motor housing and blade also slide in and out, increasing the length of the cut. For those who are interested in this site check out the links and feel free to sign up for my newsletter Wood Shop News. The miter saw is typically purchased with a fairly coarse blade pre-installed (suitable for cutting joists and other rough work).

B -miter: Flipping the board end-for-end changes sign of only the miter angle, but it also moves the waste piece to the other side of the blade. If your mitered corner is at the standard 45 degree angle((360/2)/corners), then you’ll need a gap at the end equal to the depth of the piece of wood. Biscuit joints are great for joining the edge of one board to the face of another.


Sliding miter saws and radial-arm saws have a tendency to self-feed which leaves the wood torn and ragged and can sometime even grab the stock—a potentially dangerous situation. Woodworkers also use biscuits, keys, and splines, any of which may serve as a decorative accent if created from a contrasting wood species. Miter joints and butt joints have identical miter angles; only the bevel angle is different.

The sharp 20 degree top bevel easily shears tough end-grain for gap-free miter joints. Start by laying all four parts inside-face down on a flat bench with mating corners paired together. After cutting, use a carpenter square to check the cut to see if your miter saw is capable of making accurate cut. A sliding miter saw on the other hand can cut lumber up to 9×3 thanks to its cutting head which is capable of sliding on a rail. I’m an unhappy Harbor Freight customer so I’ll vote worthless” … though to be fair I haven’t used their miter boxes. Long trim pieces are difficult to hold steady unless you support the end that hangs off the saw table.

One way is to use a special frame clamp (Photo 5) or web clamp that applies pressure on all four corners of the assembly as the clamp is tightened. If all is working correctly and you are using a sharp, appropriate blade, the vast majority of your cuts should be near glass smooth and trouble free. Typically, a 10-inch miter saw will cut a 2 x 6 at 90 degrees and a 2 x 4 at 45 degrees; a 12-inch miter saw will cut a 2 x 8 at 90 degrees and a 2 x 6 at 45 degrees. This saw cuts with great accuracy and provides a laser sight and weighs in at 46.3 pounds.

The actual amount of cove caused by a slightly out-of-line (within manufacturer tolerance) blade is all but impossible to see or measure with tools commonly used in woodworking. Always make sure you know where the short and long sides of your wood need to be. Make use of a laser guide if your machine has one (most newer machines do). I watched this saw get day in and day out abuse from students who cut too fast, started the saw while touching the work, let the saw run too long, let the saw snap back to its upright position, chopped wood not against the fence, never cleaned the blade or used wicked dull blades all day.

I’d advise either using an epoxy glue to glue the steel into the timber and take up any tolerance, or wedge the steel tightly into the timber using timber wedges or maybe standard plastic packers or wedges, but you can get away with using PVA wood glue for the timber itself. In most cases, precisely aligning the major settings on a miter gauge will make all other settings on its scale very accurate. If you’re a contractor who owns a miter saw for 10 years, you should probably stick with that brand.

Start the saw at the top of the operating position, allow the motor to come up to speed, and bring the saw down into the wood. I think that a spline would be a good way to join the two pieces using a hot melt PUR so that it will give a bit before it shows an open joint. A spinning miter saw blade took a sizeable chunk of flesh from the tip of a finger in the blink of an eye. The wood still follows the path of the miter slot, but if the blade is used as the reference, the wood is already at an angle when it meets the blade. I used the saw to cut the hundreds of tiles”, and also to cut the miters on the corners of the frame.