Rock Tumbling Grit: 4 Stages & Dosage Chart [2026]

How much rock tumbling grit do you need? First check whether your instructions give a dose per barrel or per pound of stones. Those are different recipes. Measure in the stated units, and use the dose for the current stage rather than adding the same scoop every time.

The charts below compare published instructions, not our own batch tests. For loading, cleaning, and deciding when to move on, use our beginner tumbling guide.

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How Much Rock Tumbling Grit to Use

Lortone 3A: a dose per loaded barrel

The Lortone 3A manual starts with the barrel about half to two-thirds full of mixed-size rocks. Its quantities below are for that barrel, not for each pound. Follow the manual supplied with your machine if its revision differs.

Swipe the tables sideways to see every column.

Polly Plastics: a dose per pound of rock

Polly Plastics' grit-kit instructions use rock weight. These are a separate recipe, with a different pre-polish. The last column is our arithmetic example for exactly two pounds of stones; it is not a two-pound-barrel recommendation.

If your packet gives different directions, use those for that product. Do not take a dose from one recipe and a polish from another without checking compatibility. Ask the supplier if its directions do not say whether filler media count toward the measured load.

Rotary vs. Vibratory: Do Not Copy the Dose

A vibratory bowl needs its own instructions. As one model-specific example, RockTumbler.com's UV-10 industrial-model recipe uses 6 tablespoons of medium grit, then 3 of fine grit and 3 of polish for a properly filled bowl. It excludes coarse grit to limit bowl wear. These are the supplier's working amounts, not a universal vibratory chart.

Its medium stage is rinsed and recharged after 48 hours if more grinding is needed. Water is adjusted so abrasive coats the moving stones. Do not use the rotary habit of covering the load with water. Follow your own model's bowl-fill and water guidance.

Still choosing between machines? Our three budget rock tumbler kits show which starter supplies to check before you buy separate refills.

What Tumbling Grit Actually Is

Grit is the abrasive that works between the stones. Silicon carbide is common for grinding: it is a manufactured material, about 9+ on the Mohs hardness scale, suited to working stones such as quartz, agate, and jasper. RockTumbler.com's grit explainer describes how it is made and used.

Polish is a finer abrasive product, often aluminum oxide. Filler media are something else again: ceramic pieces or plastic pellets help manage the load. Do not count a bag of filler as one of your grit stages.

The Four Stages of a Typical Rotary Recipe

The job changes from shaping to smoothing to polishing. Products and grades vary; the named recipes above show why a stage number alone is not enough to choose a refill. Compare abrasive grades with the instructions for the product you are using.

1. Coarse grind: removes edges and changes the shape. 60/90 silicon carbide is a common choice.
2. Medium grind: works on the scratches left by coarse grit. Labels include 120/220, 150/220, and 180/220.
3. Fine grind or pre-polish: prepares the surface for polishing. This may be fine silicon carbide or a specified aluminum oxide product.
4. Polish: develops the final finish on stones that are ready for it. Use a rock polish, not another bag of coarse or medium grit.

Buy a Kit, or Buy Stages?

Choose a kit when you need every stage. Check that it contains a final polish as well as grinding grits, and read the dose per batch. Bag weight alone does not tell you how many batches it will finish. The National Geographic refill is one four-stage option to compare.

Need filler too?Compare the MJR kit's included materials with your machine's instructions. Check the package size and media type before ordering; use its own dosing directions.

Buy an individual refill when one stage runs out

Repeated shaping runs can use up coarse grit before the rest of a kit. Compare the delivered cost of the stage you need with the cost of a full replacement kit. Keep the grit grade visible on your shopping list.

These buying links are separate from the dosing charts. The Lortone table is not a recipe for every kit linked here. We have not compared these refills in our own controlled tumbling test.

Can You Use Sand Instead of Tumbling Grit?

Sand is not a like-for-like refill. Common quartz sand does not offer the same hardness and controlled grade as silicon-carbide tumbling grit. Choose a product with a stated abrasive and grit size, rather than expecting beach or play sand to follow a kit's grinding schedule.

Rock choice matters too. Our Mohs hardness field guide helps you check the material before mixing a batch.

Mistakes That Waste a Batch

• Mixing units or recipes. Record the product, dose, and units. Do not convert a scoop to ounces by guesswork.
• Carrying grit into a later stage. Clean the barrel, lid, stones, and tools before changing abrasive.
• Mixing unsuitable stones. Keep similar materials together; soft or fractured pieces can spoil a batch.
• Ignoring the fill level. Follow the machine's instructions and load limit as well as the grit recipe.
• Rinsing slurry down a drain. Collect it in a bucket and follow local disposal guidance. Rock mud can block pipes.

For the cleaning and inspection steps, see RockTumbler.com's rotary instructions. When handling dry powders, follow the supplier's dust and eye-protection instructions.

Before the next run: write down your machine, stone weight, abrasive, measured dose, and start date. That gives you something useful to compare when a batch needs more work. Our editable batch log gives you a place to keep those notes. If the final polish disappoints, work through the checks for dull stones and scratches.