10 Things Every Woodworker Should Know

There is a lot to woodworking, and most of us don’t realize how much we don’t know when we first start out.

I’ve been woodworking for 50 years, and I can tell you there are plenty of things I wish I had understood much earlier. Some of them are simple shop habits. Some have to do with buying lumber, measuring accurately, or understanding how wood behaves. Others are the kind of lessons you usually learn the hard way, after a board warps, a glue-up fails, a cut comes out short, or a finish doesn’t look the way you expected.

That is part of woodworking. You learn by doing. But if someone can point out a few of these things ahead of time, it can save you a lot of frustration, wasted material, and head-scratching in the shop.

These are not the only things a woodworker needs to know, but they are some of the most useful ones. Whether you are just starting out or you have been building for years, understanding these basics will help you work more accurately, avoid common mistakes, and get better results from your projects.

How hardwood lumber is dimensioned

Most woodworkers start by buying construction lumber from a lumberyard or home center. That usually means pine boards like 1x4s, 1x6s, or 2x4s.

But those names are not the actual finished sizes. A 1x4 does not measure 1 inch thick or 4 inches wide. It started that size when it was rough cut, then it was planed and surfaced. By the time you buy it, it is usually about 3/4 inch thick and somewhere around 3 1/4 to 3 1/2 inches wide.

Construction lumber is usually sold by the stick. A 1x4x8 has one price, a 1x4x10 costs more, and so on.

Hardwoods are sold differently.

When you buy hardwood lumber, thickness is usually measured in quarters. A 4/4 board is four quarters, or about 1 inch thick in rough form. A 5/4 board is about 1 1/4 inches thick, and a 6/4 board is about 1 1/2 inches thick.

The key phrase there is “rough form.” If the hardwood has already been surfaced, it will usually be thinner. A surfaced 4/4 board may end up closer to 3/4 inch. A rough 6/4 board may finish closer to 5/4 after it has been flattened and smoothed.

Hardwoods are also sold by the board foot, not by the stick. A board foot is a volume measurement: 12 inches by 12 inches by 1 inch thick, or 144 cubic inches.

So if a board is 30 inches long, 6 inches wide, and 1 inch thick, it contains 180 cubic inches, which is about 1 1/4 board feet. If that lumber costs $20 per board foot, that piece would cost about $25.

When buying from a hardwood supplier, they will usually want to know the thickness, the number of board feet, and sometimes the minimum length or width you need. If you need boards for a 6-foot tabletop, for example, you should specify a minimum length of 6 feet.

Random-width and random-length boards are usually cheaper. If you want specific sizes, many suppliers can provide them, but they often charge more.

I also recommend buying extra. If I need 6 board feet of walnut for a project, I might buy 10. That gives me room to cut around knots, wane, defects, or grain I don’t like. The leftovers usually become useful later anyway.

Moisture level

All wood contains moisture when the tree is cut down. In fact, a large part of a fresh tree’s mass can be water. Before that wood is useful in the shop, much of that moisture needs to leave.

Good hardwood has usually been dried, either by air drying or kiln drying. Construction lumber from a home center or local lumberyard may only be air dried, and sometimes not as well as you might expect.

That moisture matters because wood does not always dry evenly. I’ve had straight boards warp badly after cutting them down. A 2x12 might look fine as a full board, but once it’s ripped into smaller pieces, the internal stress or trapped moisture can show up fast. One part dries faster than another, shrinks differently, and suddenly you have a bowed or twisted board.

That is why a moisture meter is a good investment. I wish I had learned that much earlier. You can spend a lot on one, but even an inexpensive meter is better than guessing. Some have sharp probes that leave tiny holes, while others have flat sensors that do not mark the wood as much. Most also have different settings for different wood types, so choose the scale closest to the wood you’re checking.

When you bring lumber into the shop, especially construction lumber, assume it may not be dry enough. Let it acclimate before building with it. Store it flat, keep it supported, and weigh it down if you can. Give it at least a few days, or a week if possible.

Air conditioning or a dehumidifier can help if your shop allows for it.

For most woodworking projects, I want the wood below 10% moisture content before I use it. Ideally, it should be around 8% or 9%. If it is higher than that, give it more time to dry.

How to mark wood accurately

Good projects start with accurate measuring and marking. How accurate you need to be depends on what you’re building.

If you’re framing a wall, being off by 1/8 inch may not matter much. If you’re building a picture frame, a box, or tight joinery, that much error is huge.

A lot of woodworkers use a tape measure for everything. I only use a tape measure when the part is too large for something better. For most shop measurements, I prefer a steel ruler. I have a 12-inch ruler, a 24-inch ruler, and a graduated steel square. A good etched steel ruler gives me a much more accurate mark than a tape measure or a printed ruler.

What you mark with matters too. I don’t use carpenter’s pencils for fine work. I use mechanical pencils, usually 0.7 mm or 0.5 mm, because they leave a much finer line.

Even then, you have to pay attention to how you hold the pencil. If the pencil leans away from the ruler, the line can end up off by half a millimeter or more. For tight work, that matters. Angle the pencil into the ruler so the mark lands where you actually want it.

For even more accuracy, use a marking knife. A marking knife has a flat side that rides right against the ruler, leaving a precise cut line. That is what I use for joinery like dovetails, box joints, and lap joints.

Use relative measurements, rather than drawing measurements

Once a project starts going together, don’t rely only on the measurements from the plan. Measure from the actual workpiece.

Small errors add up. Maybe one part is off by 1/64 inch. Then another is off by the same amount. After a few parts, that can turn into a visible gap. That’s called tolerance stack, and it happens in the shop just like it happens in industry.

A better method is to mark parts directly from the piece they need to fit.

If I’m adding a shelf or support to a small workbench, I don’t want to trust a number on a drawing if the assembled piece has changed slightly. I can put the support where it needs to go, mark it directly, and cut to that line.

This is especially helpful with dimensional lumber because boards are not always the exact size you expect. A 1x8 may not be exactly 7 1/4 inches or 7 1/2 inches wide. If you assume the size and cut from that assumption, the part may be wrong. If you mark it directly from the project, the mark is exactly where it needs to be.

Relative measurements save a lot of headaches.

Accounting for saw kerf

Every saw cut removes material. That removed material is called the saw kerf.

The kerf is the width of the blade’s cut. On many saw blades, it is close to 1/8 inch, though some blades are thinner. A bandsaw usually has a narrower kerf, but it still removes material.

This matters whenever you are laying out cuts. If you have a 24-inch board and want two 12-inch pieces, you cannot get them by cutting the board in half. The saw blade removes material, so one or both pieces will end up short depending on where you cut.

The same thing applies when breaking down sheet goods. A 4x8 sheet is 48 inches wide. If you want three shelves at exactly 16 inches, the math looks right until you account for the two saw kerfs. With an 1/8-inch blade, you would actually need 48 1/4 inches of material. The simple fix is to make the shelves slightly narrower, around 15 7/8 inches, so all three come out of the sheet.

You also need to account for kerf when cutting multiple parts from one board. Three cuts from an 8-foot board can remove almost 3/8 inch of material. If you ignore that, your last piece may come out short.

For accurate work, sneak up on the cut. Instead of cutting exactly to the final line right away, cut slightly long, check the fit, and trim again if needed. That gives you control and helps avoid gaps.

Keep your tools sharp

Anything that cuts wood needs to be sharp. That includes saw blades, drill bits, router bits, chisels, hand planes, and any other cutting tool in the shop.

Factory sharp is usually good enough to get started, but it is not always sharp enough for fine work. Chisels and plane irons especially need to be honed if you want clean cuts. If you’re cleaning up dovetails or using a hand plane for a finished surface, sharp matters.

Saw blades are a little different. Most of us are not set up to sharpen table saw blades ourselves. If a blade gets dull, I either replace it or send it to someone who sharpens saw blades professionally.

Router bits can often be touched up with a diamond plate. The flat face of the cutter is the part doing the cutting. Lay that flat surface on the diamond plate and take a few light strokes. You don’t need to remove much material, just freshen the edge.

One sign a tool is getting dull is tear-out. Another is light reflecting off the cutting edge. If you can see a shiny flat spot on the edge of a chisel or plane blade, that edge is no longer sharp.

Sharp tools cut cleaner, work easier, and are safer to control.

How to avoid splitting wood

A very common problem for new woodworkers is splitting wood when fastening pieces together. Most of us start out using plywood or dimensional lumber, and we often put those projects together with screws. There is nothing wrong with that, but screws can split wood if you do not make room for them.

When a screw goes into the wood, it can act like a wedge. It pushes between the grain and forces the wood apart. That is why you may drive a screw into a drawer, box, toy chest, or simple shop project and suddenly split the board.

The easiest way to prevent that is to drill a pilot hole.

A pilot hole gives the screw body a place to go, so the screw is less likely to force the wood apart. For an even better connection, drill a clearance hole in the first piece and a pilot hole in the second.

The clearance hole should be large enough for the screw to slip through the first piece without the threads really biting into it. The pilot hole in the second piece should match the screw’s minor diameter, also called the root diameter. That is the center body of the screw without the threads.

For a typical #8 drywall or construction screw, a 1/8-inch pilot hole is usually about right.

You can also buy tapered drill bits that make this easier. These bits combine a pilot hole, clearance hole, and countersink in one step. They come in different sizes for different screws, and they are handy if you use screws often in your woodworking projects.

Proper Gluing

A lot of woodworkers struggle with glue-ups, especially edge gluing boards for tabletops, panels, or shelves. Good gluing comes down to three things: how much glue you use, how much clamping pressure you apply, and how you clean up the squeeze-out.

For PVA wood glue, which is the common yellow or white wood glue most of us use, the glue works by soaking into the pores of the wood. That means the mating surfaces need to be clean. If an old glue joint failed or had to be taken apart, scrape the old glue off before trying again. You need fresh wood pores for the glue to bond properly.

There is some debate about whether to apply glue to one surface or both. I go by what the manufacturers say, and they generally recommend applying glue to one mating surface. Spread it into a thin, even film. You do not need a thick layer. If you have full coverage and a little squeeze-out when the boards come together, you have enough glue.

Clamping pressure is another place people overdo it. If you have to crank down hard on the clamps to close a gap, the problem is not the clamps. The problem is that the boards were not prepared properly.

Before adding glue, dry fit the joint. Make sure the edges meet cleanly. If there is a gap, fix the edge first. Clamps are meant to bring the joint together, not force badly prepared boards into shape.

You do not need extreme pressure. Whether you are using parallel clamps, F-style clamps, pipe clamps, or quick-action clamps, the goal is simply to close the joint and get a small amount of squeeze-out. If you are crushing the wood or fighting the clamps, something is wrong.

Then comes cleanup.

Some people wipe wet glue off right away. The trouble is that wet glue can smear into the pores around the joint. Later, when you stain or finish the project, that area may show up as a blotch or light spot. If you are painting, it may not matter. But with a clear, transparent, or semi-transparent finish, it can.

A better method is to let the glue set up before scraping it off. Many woodworkers leave the panel clamped for 30 minutes to an hour, scrape the squeeze-out while the glue is firm but not fully hard, then put the clamps back on and let the joint finish curing. At that stage, the glue is less likely to smear, but still soft enough to remove cleanly with a chisel or a scraper.

The importance of proper sanding

No matter what finish you plan to use, the finishing process starts with sanding. That applies to paint, varnish, lacquer, shellac, epoxy, or anything else you put on wood. If the sanding is poor, the finish will show it.

Sanding removes burn marks, rough spots, scratches, machining marks, and any uneven surface texture left behind from cutting or milling. Even a board that looks good can still feel rough when you run your hand across it.

If you are going to buy one sander for your shop, I recommend a random orbital sander. It is one of the most useful sanding tools for general woodworking, and the hook-and-loop sanding discs make it easy to move through the grits.

The grit number tells you how coarse the sandpaper is. Lower numbers remove material faster. Higher numbers leave a smoother surface.

If a board has burn marks or rough spots, I may start with 60 grit. From there, I usually move to 100, then 180, and finish with 220. You can generally skip one grit level, but don’t jump too far. Each grit is meant to remove the scratches left by the previous one.

For most projects with a film finish, 220 grit is plenty. By film finish, I mean paint, varnish, lacquer, shellac, or anything that sits on the surface of the wood. The finish will fill the tiny scratches left at that stage. Sanding much finer than that can waste time and may even make it harder for the finish to grab onto the surface.

The grit you will spend the most time with is the first one. That’s the grit doing the real cleanup. Once the burn marks, rough spots, and damage are gone, the finer grits go much faster.

Sanding speed matters too. A lot of people move the sander back and forth too quickly. A good rule is to move about one inch per second. Let the sandpaper do the work. If the mark or rough area is still there, go over it again instead of rushing.

I rarely sand to 320 unless I’m sanding very lightly between coats of finish. If a piece will be waxed and polished, that may be different. But for most woodworking projects, 220 is a good stopping point before finishing.

One more thing: finish both sides when you can. The show side may get three, four, or more coats, but the back side should still be sealed. Even one or two coats will help slow moisture movement and keep the board more stable.

Always test finishes on offcuts

Stain can be tricky. The color on the can, the sample card, or even the display board at the store only gives you a rough idea. The final result depends heavily on the wood you apply it to.

The same stain can look completely different on pine, pine plywood, oak plywood, maple, or any other species. Even two pieces of the same general type of wood can take stain differently.

Pine is a good example. It can be difficult to stain because it has resin in the wood and often absorbs stain unevenly. That can lead to blotchy areas, with some spots turning dark and others staying light.

Oak is much more porous, so it usually accepts stain readily, especially in the open grain. Maple is the opposite. It is not very porous, so stain often has a harder time soaking in.

That is why you should always test stain on an offcut from the same wood you are using for the project. Don’t just grab a random scrap of pine because your project is pine. Different boards, different species of pine, and even different plywood veneers can all react differently.

Use a real offcut from the project, sand it the same way, and apply the stain and finish the same way. That is the only way to know what the finished piece will actually look like.

Final Thoughts

These are not the only things a woodworker needs to know, but they are lessons I see people struggle with all the time.

Woodworking is a craft where you keep learning. I’ve been at it for 50 years, and I’m still learning new things. That’s part of the fun. The more you learn, the more confidently you can build, solve problems, and take on better projects.