It allows for some fiddling around with your alignment as the biscuit joiner will oversize the slot for the biscuit a bit allowing you to line up the joint. Ok-I can’t help myself: Biscuit joints vs. Doweling quickly summarized: Biscuits: More play, faster, more expensive tools, better pull-apart strength. I’m merely a carpenter, and there won’t be much-if any stress on my joints so a biscuit will work just fine.
Miters make a great choice for frames because they hide end grain, and the joint lines direct your eye to the framed item. With lots of face-grain-to-face-grain gluing surface, half-laps make a strong choice for large frames and those that need to support heavy objects such as mirrors. Another way to create an eye-catching frame without miters is to assemble it with a chasing or pinwheel pattern, rather than capturing the rails between the stiles.
Just a bit on the terminology, a true spline runs lengthways in a slot milled into the face of both mitres, through all or most of the joint. Mitre keys are generally regarded as not adding greatly to the strength of the joint, while splines do provide a significant improvement. “The strength of each reinforcement is due to three factors: structural advantage, the thickness of the wood slivers used and the glue surface area. The splined joint being superior in all regards. However, mitre keys were originally quite small and done using veneer thicknesses, resulting in only modest added strength while the keys in the video on the other hand are far larger than conventional ones and also thicker. So they probably add as much, if not more, strength than a typical spline would, being of relatively modest width.”If you use either sizeable mitre key or fairly wide spline, using wood of some thickness I think it likely that you will end up with joints that are strong enough.
how to use a biscuit joiner to make picture frames Related Question:
What angle should I make a picture frame?
Use a miter saw to cut one end of both boards at a 45-degree angle, being careful to make sure that the rabbet runs along what is to become the inside of the frame. In other words, once you have finished cutting an angle into each board, the rabbeted edges should be opposite the longer (and pointier) side.
Can you biscuit joint a 45 degree angle?
Mark the center lines for each biscuit to align with the biscuit joiner. Most biscuit joiners have a variety of fence positions; on a 45-degree miter, the fence should be on the 45-degree setting. After test cuts, it is a very fast operation!