Phase 02 — Stone, bone, wood and fibre toolkit / About year 1
02.04
Sandstone grinding slab
grinds and sharpens stone, bone and wood
AWhat it needs
Needs 1 other product.
View
- 02.04 Sandstone grinding slabMaking Year 1 needs 1 product
- 01.02 HammerstoneMaking Year 1 raw materials only
Open a box to see what it needs. A dashed box is a product already drawn in full: click it to jump there. In the org chart, drag to move around.
BWhy
Flaking shapes stone by breaking it. Grinding shapes stone, bone, shell, antler and wood by rubbing them away, slowly and exactly. It gives smooth points, true flats and tough edges that flaking cannot.
CYou need
- Two flat slabs of sandstone, each as long as the forearm: one coarse and gritty, one fine
- A hammerstone (01.02)
- Sand and water
DSteps
- Look where sandstone splits naturally into slabs: stream banks and cliff feet. Good sandstone feels like rough skin and sheds a few grains when rubbed hard.
- Knock off any lumps with the hammerstone.
- Flatten the two slabs against each other. Wet them, throw on a handful of sand, and rub one over the other in circles until both faces touch all over.
- Set the coarse slab on the ground, tilted a little away from you, with water and sand beside it.
- To grind: wet the slab, add a pinch of sand, and push the piece away from you in long strokes, pressing down. Rinse the slab often so the mud does not clog it.
- Use the coarse slab to shape and the fine slab to finish.
- For round things such as needles and arrow shafts, rub a straight groove into a third piece of sandstone with a stick and sand, and draw the piece along the groove while turning it.
- When a slab wears hollow, rub the two together again to bring it flat.
EIt worked if
- A splinter of bone is ground to a sharp point in a few minutes.
- A straight stick laid on the slab touches it along its whole length.
FWhat goes wrong
- The slab sheds grains by the handful. The stone is too soft. Look for a harder bed.
- It goes smooth and stops cutting. Roughen it by pecking lightly all over with a hammerstone, and add fresh sand.
- The work piece grinds lopsided. Count strokes and turn the piece evenly.
GIn the story
Luca is a mason with no chisel, no mortar and nothing to build with. Finding the right stone is the first job on the island that is his. He comes back carrying two slabs on his shoulder and sets them down by the fire like a gift to the whole camp.
HFigures
not drawn yet
not drawn yet