Every woodworker makes mistakes, and most of them are the same few mistakes. Time and experience teach how to avoid them. Knowing the common ones in advance saves wood, time and frustration, and for a woodworking business, it saves money: every remade part or reworked finish is time and material you cannot charge for.
This post covers twelve of the most common problems, how to fix each, and how to stop it happening again.
12 Common Woodworking Mistakes
1. Going Too Fast
Rushing is behind more spoiled projects than any single technique. A missed step, a wrong measurement or a cut on the wrong side of the line usually happens when you hurry. It is also the main cause of accidents.
Avoid it: at each critical stage, stop and check what you are about to do before you do it. Measure twice and cut once. Fixing a rushed mistake almost always takes longer than doing the step carefully. If you notice you are rushing, stop; it is unsafe as well as costly. See woodworking safety rules.
2. Drawers and Doors That Do Not Fit
You build a whole cabinet from a plan, and the drawers come out the wrong size. Small differences between the plan and the real piece add up, and drawers need a close fit.
Avoid it: build the carcass first, then measure the actual openings and make the drawers and doors to fit them. Measure from the piece, not from the plan, whenever one part must fit another.
3. Blotchy Stain
Some woods absorb stain unevenly, leaving dark patches. Finishing expert Bob Flexner explains that blotching is caused by uneven density in the wood. He lists pine, spruce, fir, aspen, poplar and alder as woods that almost always blotch, and cherry, birch and soft maple as woods that usually do. Oak, ash and mahogany rarely blotch.
Avoid it: test the stain on scrap of the same board first. On woods that blotch, Flexner recommends gel stain, which sits more on the surface. A thin washcoat of finish before staining also evens out absorption. You can also choose a clear finish or paint for woods that blotch.
Fix it: blotching cannot be fixed by stripping and restaining. Flexner notes that you may need to sand or plane off as much as 1/32 inch to get below the dark areas, so prevention is far easier than repair.
4. Stain That Does Not Take
Light patches that refuse stain are usually caused by dried glue squeeze-out or by wood filler that does not accept stain. Glue seals the wood, so stain cannot soak in.
Avoid it: keep glue off visible surfaces (see the tape trick in types of wood joints), and remove squeeze-out carefully. Before staining, wipe the surface with a cloth dampened with mineral spirits; glue spots show up as light patches. Use a stainable filler and test it first.
Fix it: scrape or sand away the glue spot down to bare wood, then restain. It is much easier before any finish is applied.
5. Fuzzy or Raised Grain
Some woods leave fine fibers standing up after sanding, and water-based stains and finishes raise the grain further, leaving a rough feel.
Avoid it: sand with sharp, fresh sandpaper, working through the grits without skipping. Before a water-based stain or finish, wipe the surface with a damp cloth to raise the grain on purpose, let it dry, then sand lightly with your final grit. The fibers will not rise as much again.
Fix it: if fuzz appears after a first coat, let it dry and sand lightly with fine paper before the next coat.
6. Joints That Are Too Tight
A joint that needs a hammer when dry will be tighter once glue makes the wood swell, and may split the wood or never close fully.
Avoid it: always dry fit. A good joint goes together with hand pressure or light taps with a mallet. Trim tight tenons with a shoulder plane or chisel until they fit. Assemble each joint fully before moving to the next; a joint that is only partly assembled can lock up as the glue grabs, and may be impossible to separate without damage.
7. Joints That Are Too Loose
A loose joint is weak, because glue needs close contact between the parts to hold well.
Fix it: glue a thin strip of wood to the loose part, such as a tenon cheek, let it dry, and trim it to fit. For slight gaps, gap-filling epoxy holds better than ordinary wood glue. Do not rely on extra glue to fill a gap.
8. Tear-Out
Tear-out is when wood fibers break out of the surface instead of being cut cleanly, during planing, routing or sawing.
Avoid it: keep blades and bits sharp, plane and rout with the grain, take lighter passes, and back up cuts with scrap where a bit or blade exits. When cutting plywood, put the good face up on a table saw and down on a circular saw or jigsaw. See how to measure, mark and cut wood.
9. Burn Marks
Dark burn marks from a saw or router come from a dull or dirty blade, feeding too slowly, or the wood pinching the blade.
Avoid it: clean resin from blades and bits, keep them sharp, feed at a steady rate, and check that the table saw fence is not angled towards the blade at the back. Remove burns with a scraper, a sanding block or a light plane pass.
10. Cracks and Warping After Assembly
Wood swells and shrinks with humidity. If a piece is built without allowing for this, panels crack, joints open and tops cup, often weeks after the piece leaves your shop.
Avoid it: use dry wood and let it rest in the shop before building. Let solid panels float in their frames, and fix tabletops with fasteners that allow sideways movement. Finish both sides of a panel or top, so moisture moves in and out evenly. See types of wood for woodworking.
11. Wobbly Tables and Chairs
A table rocks because its legs are uneven, its frame is twisted, or it was glued up out of square.
Avoid it: check the frame for square by measuring the diagonals during glue-up, and assemble on a flat surface. Fix it: place the piece on a flat surface, shim it until it sits level without rocking, then mark and trim the long legs.
12. Surfaces That Are Not Flat
Boards that were not flattened properly, or panels glued up with uneven joints, leave a surface with ridges and hollows that show under finish.
Avoid it: joint and plane boards before glue-up, alternate the growth rings in glued panels, and use cauls to keep panels flat while clamping. Fix it: flatten with a hand plane, then smooth with a sander or card scraper.
Preventing Mistakes in a Woodworking Business
- Write down your process for products you make often, including measurements, settings and finishing steps.
- Use jigs and stops for repeated parts, so measuring errors cannot creep in. See woodworking jigs and batch production.
- Test on scrap before every new stain, finish or setup.
- Check the first piece of every batch before making the rest.
- Inspect every piece before it ships. Catching a flaw in the shop costs far less than a return or a poor review.
- Keep a mistakes log. Note what went wrong and why, so the same mistake does not cost you twice.
For help with a specific problem, search woodworking forums, magazines and videos, or ask at a local woodworking club. Most problems have been solved many times before.
For sanding, finishing supplies and applying finish, see wood finishing for a small shop.
Sources
- Flexner, 2004, Flexner on Finishing: Battling Blotching, Popular Woodworking
