Detail Sander Grit Guide: When to Use 80, 120, 180, and 240 Grit Sandpaper

For furniture, start with 120 grit if the wood is already fairly smooth. Drop to 80 only when deep scratches, gouges, or uneven glued joints need to come out. After that, the finish you plan to use decides where you stop: 180 is one published stopping point, and 240 has one clearly documented job, which is sanding between coats of a lacquer that calls for it.

These numbers come from general wood-sanding advice and practical woodworking guidelines rather than tool-specific detail sander specifications. In short, the surface you have sets your starting grit, and your planned finish sets your last.

When to Use 80, 120, 180, and 240 Grit

Each grit has its own job, but none of them is required on every piece. When working with an electric detail sander on tight furniture profiles, use the table below to match a grit to the surface or finish step in front of you.

Pay attention to the grade label before you buy. A general sandpaper reference says most North American woodworkers only need the CAMI grit system. European grades carry a "P" before the number and run a little coarser at the same number. So a P240 sheet and a 240 sheet are not exact substitutes. Match the system your finish instructions use.

Choose a Starting Grit from the Surface You Have

Look at the surface before you pick a grit. The advice for choosing a starting detail sander grit depends on how much damage needs removing, not on a fixed recipe.

• Fairly smooth, sound wood: Start at 120. The WOOD Magazine rule of thumb says 120 smooths the surface quickly without leaving deep sanding scratches. If you start coarser than you need, you add scratches that you then have to sand out.
• Visible damage: Start coarser, at 100 or even 80. This covers deep scratches, gouges, ripples from a planer or jointer, uneven joints after gluing, or a lot of surface flaws. On these surfaces, a finer start may not take the defects out efficiently.

Treat 80 as a fix for damage, not a default for every refinishing job. If only one area of a tabletop or drawer front has gouges, that area is what calls for the coarse start. A clean panel next to it can still start at 120.

Progress Only as Far as the Surface Needs

Move to a finer grit once the current one has removed the defects you chose it for. Each finer grit's job is to erase the scratches left by the grit before it. You skip grits at the ends of the range, not in the middle.

1. Start at the grit the surface calls for. That means 80 for real damage and 120 for wood that is already fairly smooth.
2. Sand until the target defects are gone. At this point, the only marks left should be the scratches from the grit you are using. If a defect is still visible, keep working at this grit before you move on.
3. Step to the next finer grit you have chosen. WOOD Magazine explains that finer grits remove the previous grit's scratches. It advises working through your chosen steps instead of jumping ahead.
4. Stop at your finish's endpoint. If your finish stops at 180, going on to 240 adds work without a documented benefit for that finish.

So you never need all four grits by default. A smooth chair rail might go 120 to 180 and stop. A gouged dresser top might start at 80 and still end well below 240.

Let the Finish Set the Stopping Point

No single final grit works for every furniture finish. Published woodworking advice differs by finish and by source, so use these values as examples:

• One WOOD Magazine answer says you can stop at 180 for an oil or clear finish and go on to 220 for stain or dye.
• A different WOOD hand-sanding recommendation stops at 180 before some film-forming finishes and goes to 220 before oil.
• Woodworking Network's broad 180-to-240 range covers getting a fairly smooth surface before finishing. It does not tie 240 to any specific finish.

Notice that the two WOOD guides disagree about oil. That is why the instructions for your exact finish should decide the endpoint. Sanding between coats is a separate step with its own grits. In WOOD's finish-sanding walkthrough, the bare wood goes to 220, the first coat is buffed with 220, and the next coat with 320. Advice written for 220 does not carry over to 240. Use 240 when your finish system calls for it, as the Amarium lacquer does between coats.

FAQs

Do I need all four grits on every furniture project?

No. Many pieces only need two or three grits. Sound wood can skip 80, and a finish that stops at 180 makes 240 unnecessary. Between your first and last grit, move through each step you have chosen so every finer grit can clear the marks from the one before it.

Is 240 grit a good final grit for bare wood furniture?

There is no general rule that it is. One woodworking reference includes 240 at the top of a broad prefinish range. The only direct 240 instruction found here is a professional lacquer's 240-to-320 range for sanding between coats. Use 240 on bare wood only when your finish's instructions call for it.

How do I know it's time to switch to a finer grit?

Switch when the flaws you started with, such as gouges or glue-line steps, are gone and only that grit's scratches remain. If flaws are still there, a finer grit will remove them slowly, so keep working at the current grit.

Is a P240 sheet the same as 240 grit?

Not exactly. P grades follow the European system, which runs a little coarser than CAMI grades at the same number. Most North American woodworking advice uses CAMI numbers, so check which system your finish instructions use.