1. Why skipping grits fails
A coarse grit cuts deep scratches; a finer grit cuts shallower ones. If the next grit is much finer, its grains ride on the peaks between the old scratches and never reach the bottom of them. The surface looks fine after the fine belt — until a polish, a coat of paint or a raking light shows the old pattern underneath. Woodworking abrasive guides describe the same result as an uneven, blotchy finish, and point out a second cost: the fine belt is doing work it was not designed for, so it wears out faster.
2. How big a jump is safe
| Rule of thumb | What it means in practice | Source |
|---|---|---|
| Next grit no more than ~50% higher, or less than double | After 80, go to 100 or 120 — not 180 | Empire Abrasives |
| Up to a two-grit jump in roughing, one grit at a time on fine belts | 36 → 50 or 40 → 60 at the coarse end; 80 → 100 → 120 → 150 → 180 → 220 at the fine end | Woodshop News (sanding systems consultant) |
| Do not skip more than one grit | Skipping too far shortens belt life and leaves the previous scratches | Purdue University wood research lab |
These rules come mostly from wood sanding, but the reason behind them — scratch depth — applies to metal just as well. On metal you can often start coarser (rust, weld beads, scale), and the jumps between coarse grits can be larger because those steps are about removal, not finish. A common metal progression quoted by abrasive suppliers is 60 → 120 → 220 → 320.
3. Ready-made sequences with MOOSEFOS belts
| Job | Sequence | Belts (standard grits) |
|---|---|---|
| Weld removal and blending on steel | 40 or 60 → 80 → 120 | PZ633+ zirconia (40/60/80/100), WY1266 zirconia (40/60/80); WY1289 (40/60) on high-speed machines |
| Hardened steel, heat-sensitive parts | 36 or 60 → 80 → 120 | WY1599 ceramic (36/60/80/120) |
| Satin finish on stainless | 60 or 80 → 120 → 180 → 240 | WY1531 alumina-zirconia (60–400), finer passes on WY1513 (100–400) |
| Fine finish before hand work | 180 → 240 → 320 → 400 | WY1531 or WY1513 |
| Hand finishing after the belts | P400 → P600 → P800 and finer | Eagle AP806 SiC waterproof paper (P60–P10000) |
Knife makers: the step-by-step sequence for a 2×72 grinder is in 2x72 belts for knife making. To see what finish each grit gives, use the grit to Ra chart.
4. How to know a step is finished
- Change direction. Where the part allows it, grind each step at an angle to the last one. When none of the old scratch direction is left, the step is done.
- Use raking light. Look along the surface with a light low to one side; leftover deep scratches show up as lines that do not match the current pattern.
- Mark it. A common shop trick: run a marker over the surface before the next grit and grind until the marks are gone evenly.
- Clean between grits. One loose coarse grain carried onto a fine belt will cut a scratch you then have to chase.
5. Pressure changes along the sequence
The coarse end is where you lean on the work. Zirconia and ceramic belts need that pressure to break down and keep cutting; used too lightly, they glaze. At the fine end the job is an even scratch at lighter pressure, which is what the alumina-zirconia belts are for. If a belt goes shiny and stops cutting at any step, see sanding belt troubleshooting.
6. Common questions
How many grits can you skip when sanding?
As a rule of thumb, keep each step to no more than about 1.5–2× the previous grit number, or skip no more than one grit. At the coarse end you can jump further, for example 36 to 50 or 40 to 60; at the fine end go one grit at a time.
What is a good grit progression for metal?
A common progression is 60, 120, 220, 320. For weld removal on steel, 40 or 60, then 80, then 120 works for most jobs; for a satin finish on stainless, 60 or 80, then 120, 180 and 240.
Why do scratches show up after the final grit?
Usually because a step was skipped. The finer grit removed only the tops of the earlier scratches; the bottoms remain and show up under polish, paint or a raking light. Go back to the grit after the one that left the scratches.
Should I start with a coarse grit to save time?
Only if there is a lot of material to remove. Start with the finest grit that removes the material in reasonable time: a coarse start saves time on the first step and costs it back on every step after it.
Does skipping grits wear out belts faster?
Yes. The finer belt has to remove deeper scratches than it was made for, so it wears faster and may glaze, and you still may not remove the old scratches.
Sources
- Empire Abrasives — the golden rule of sanding: empireabrasives.com/blog/what-is-the-golden-rule-of-sanding
- Woodshop News — the nitty-gritty of grit sequence: www.woodshopnews.com/columns-blogs/time-for-the-nitty-gritty-of-grit-s
- Purdue University — understanding sanding grit: ag.purdue.edu/department/fnr/lab-sites/woodresearch/safety/understandi
- Red Label Abrasives — choosing a grit sequence: www.redlabelabrasives.com/blogs/news/sanding-grit-guide-how-to-choose-
Sources checked 2026-10. MOOSEFOS model data is from our own product pages.