The Tumble Batch Planner

The RockHoundry method for turning a mixed haul into barrels that finish together: tested, named, screened, sorted by hardness and costed in grit and days

RockHoundry's Tumbling Grit Schedule Calculator asks for one Mohs number and gives every stage the same days, and its own page warns that softer rocks in a mixed batch finish, or disappear, before the harder ones are ready. The Mohs Hardness Calculator that should supply the number gives a range instead: a stone that beats the steel file is only "6.5 or harder", and fluorite comes out 3.5 to 5.5, straddling the point where the days change. The Tumble Batch Planner joins the site's tools. Its worked haul of 114 stones is bracketed with the scratch kit, named with a specific gravity test, and screened: the galena and the selenite never go in a barrel. Typed at the calculator's default of 7, the fluorite and calcite would get 28 days of grinding on a 16-day schedule, 75% more than they need. Sorted into one hardness band per 3 lb barrel instead, each band gets its own schedule, the hard band runs now at 72.9% stones, and the soft band, 79.9% filler, is shown costing 9.97 tablespoons of grit per pound of its own stones before anyone pours it. Every worked figure is an example you replace with your own, and rules of thumb are called rules of thumb. The planner carries the safety facts: UV-blocking eyewear with a 254 nm shortwave lamp and never aimed at people or pets, toxic and radioactive minerals never tumbled or licked, slurry never down a drain and grit never dry-swept, and collecting only with permission. You get a 23-page printable PDF with seven steps, a haul log, a batch planner, a barrel log, reference tables and a quickstart, plus a personalised sheet worked out from the numbers you entered in our calculators.

Look inside

Two full pages from the planner, exactly as printed. Click either to read it at full size before you decide.

What is in it

• The scratch bracket: four field tools on one stone of every kind, and why the answer is a range
• The second test: specific gravity plus the bracket, narrowed to the minerals that fit both
• The barrel-door screen: toxic, radioactive, fingernail-soft and soluble stones kept out, with the UV uranium check
• The softest number: what to type into the tumbling calculator, and what the default does to soft stones
• One band per barrel: each band weighed against the barrel's rated load, with the filler it needs
• Grit, calendar and the clean change: grit costed by the load, a halfway check each stage
• The wet waste: slurry settled and bagged, never down a drain, and no dry sweeping
• Working pages: a haul log, a batch planner and a barrel log
• Reference tables: the Mohs scale with our calculator's days, and seventeen minerals through the screen
• A quickstart, and a personalised sheet worked from the numbers you entered

The planner picks up where the free Tumbling Grit Schedule Calculator leaves off. The calculator takes one Mohs number and gives every stage the same days; the planner works out which number to type for a mixed haul. It brackets each kind of stone with the Mohs scratch kit, names it with a specific gravity test, screens out what never goes in a barrel (toxic and radioactive minerals, anything a fingernail marks), types the softest number you can defend, runs one hardness band per barrel, and costs each load in grit and days. It carries the safety facts: UV-blocking eyewear with a shortwave lamp, slurry never down a drain, no dry sweeping, and a local rock club or museum for any stone you are unsure of. The worked figures are examples; your own stones replace them.