Every trade or craft has what you might call "tradecraft," things old hands have known forever. The trouble is, they assume you probably know too, even if you don't. When you're just learning, these things are the secrets of the pros. They aren't in the instructions. Dad never mentioned them. (Did Dad know? I'm not sure.) The people at the store may not bring them up unless you ask, and the truth is that you don't know to ask...
Call me a slow learner, but there are lots of things I wish I'd known when I started woodworking. Like to hear some? Here are four, in hopes of helping someone who is starting out just like I did.
NEW TOOLS AREN'T SHARP
This comes first because knowing it would have made my woodworking more fun from day one. The new chisel, plane or knife you just bought looks sharp, seems sharp, and probably isn't sharp!
"Edge tools" nearly always need sharpening when you take them out of the box. If you use them without sharpening they sort of work, but not the way they should - and you'll never know how well they should work until they're really sharp. You'll need to do two things: flatten the back first, then sharpen the bevel. Good instructions for this are on the Internet. Even simple methods work; one of the simplest is to use three grades of sandpaper stuck to a thick piece of glass. You can buy more sophisticated sharpening equipment as you need it, which you will.
Learning to sharpen is time well spent. As an old Irish saying has it, " 'Tis no delay to stop and edge the tool."
DON'T GLUE END GRAIN
If anyone said this in shop class, I wasn't listening. Yet it's one of the keys to making anything from wood. Glue joints must, repeat must, involve long grain. We go to some trouble to make this happen. It is the fundamental goal of "joinery," in fact. It's why mortise and tenon joints, edge joints, box joints, scarf joints, biscuits, dowels and dovetails work, and why end-grain joints need nails, screws or some other device to keep them together.
It's true that you can get end grain to stay put a little while with plenty of glue. Eventually, though, the joint will fail. This is caused in large part by the next fact I wish I'd known.
WOOD MOVES - A LOT
As the humidity in the air changes, anything made of wood absorbs and loses moisture. The air we breathe is dryer in the winter and more humid in the summer, dryer in air conditioned rooms and more humid in basements. Furniture dries out in sunlight or by radiators. This makes wood expand and contract.
Actually there are two things to know here. First, wood will change dimension seasonally even if it is painted or varnished. You'll need to consider this when building things, and allow for it. It's why some doors and drawers stick in the summer but work freely in the winter.
Second, the changes are not at all symmetrical. Wood expands and contracts a lot across the grain (side to side, either radially or tangentially) and least (hardly any, in fact) in the direction of the grain.
Prove it to yourself. Look at paneled doors and walls. Do you see panels with long cracks? Those panels were almost certainly painted with enough paint to glue them to the rails and stiles on all four sides. Over several seasons the panels expanded and shrunk across the grain but, unable to break the paint, they split on a grain line instead. (Painters can prevent this by scoring the paint at the panel edges with a sharp tool after it dries.) In fact this is why paneled doors were invented: solid doors expand and shrink too much in one direction.
So a tabletop or box top won't move in the direction of the grain but will get measurably bigger and smaller across the face of the grain as the seasons pass. If you screw or glue the top to the base all around, movement will in time split the wood. You can allow for movement with elongated screw holes, tabletop buttons, floating tenons, gluing only the center of a crosspiece, and so on.
Knowing this is especially helpful whenever you want to join pieces whose grain runs in different directions and when you repair old furniture. Don't glue, screw or paint in a way that restricts the cross-grain movement.
THERE REALLY IS A DIFFERENCE IN SANDPAPER
For a long time I made do with sandpaper from whatever store I happened to be in - drug store, grocery store, big box or hardware. Then one day I ordered samples from a source of real finishing supplies. Was I shocked! The good sandpaper didn't load up; it cut far better and lasted much longer. It made what I'd been using look like a cheap imitation of the real thing (which it is). Conclusion? Cheap sandpaper wastes your time and money. This is a place where quality is worth the price. Buy the good stuff.
My list of things I wish I'd known keeps growing. What does yours look like?