The beauty of the simple lap joint is the ease in cutting it, as it is merely two timbers reduced to half of their thickness where they lap over each other. This provides a face-grain-to-face-grain joint with a good amount of connecting surface.
The scarf joint is indispensable in timber framing when you need to span a length greater than your lumber is long. The scarf joint enables you to join timbers end to end, and there are many variations of this type of joint. In this under squinted stop splayed scarf joint with pegs,
All scarf joints serve the same purpose- to join two timbers together to span a distance greater than the dimensions of your lumber. There are many variations on the basic scarf joint, and this under squinted stop splayed scarf joint is one of them.
Anytime you need to span a distance longer than the lumber you have on hand, scarf joints are a good solution. This stop bladed scarf joint with cogs and wedges is a half-lap joint with stops, also called tongues or blades. The cogs in this joint are the t-shape projections in the cogs.
Like all other scarf joints, you can use this joint to create a longer beam out of two shorter timbers. The cogs in this joint are the t-shape projections in the tenon. Since they help lock the joint in place, they also increase the bending strength against horizontal loads.
This stop bladed scarf joint with cogs takes a bit more work to cut than a simple bladed scarf joint. But the cogs (the projections into the tenon that form a t-shape) added to the stub tenons help lock the joint in place.
If you need to span a distance greater than your lumber dimensions, scarf joints are the way to go. Another variation on the scarf joint, this stop bladed scarf joint is a half-lap joint with the addition of the stops, also called tongues or blades.
The half pegged bladed scarf joint is a half-lap joint with the addition of the tongues or blades connecting one beam to the other. The blades add more surface area and create a strong, attractive joint.
All scarf joints serve the same purpose – to enable you to span a length greater than the the size of your timbers. Any scarf joint effectively creates one long timber from two shorter ones.
Looking for a way to cut down on the time it takes you to cut a knee brace, or perhaps you don’t have the tooling to cut all those mortises for the tenons? How would you like a variation that simplifies the cutting but still gives you the strength and look of traditional mortise and tenon joinery?