document updated 11 years ago, on Dec 8, 2012
How to make an engineer's shiv
If an engineer wanted to construct a shiv while in prison, how would they go about it? Assume they had sophisticated knowledge, but no tools (other than having a bit of metal available)
- find some sandstone
- visually, sandstone can be recognized by:
- being sometimes layered
(due to the sedimentation process)
- it has grains, and the grains are the size of sand
- Because sandstone is defined only by its grain size, and not what the grains are made of, its color can vary greatly. Usually tan/yellow, but may be red, orange, pink, dark red, or purplish.
- Sandstone's hardness varies, because the grain material varies. But generally its has a medium hardness, softer than most rock, but harder than talc/slate/gypsum. Smash it against another rock to see which of the two rocks breaks.
- When sandstone is broken, it tends to crumble rather than forming a clean split, because of the granular structure.
- Geologically:
- sandstone can be found at sites of ancient oceans, deserts, and rivers.
- Sandstone mining is concentrated in India, Scotland, and Algeria — places where sedimentary basins occur in the same place that sand accumulation is found.
- make the stones flat by rubbing them together
- sharpen the shiv the against the stone
there's a vast amount of information out there on how to use a sharpening stone... google {whetstone technique} or {water stone technique} or {oil stone technique}
- if you want to make it extremely sharp, progressively move on to siltstone, claystone, and maybe a strop
- sandstone: 10 - 200 grit
- siltstone: 200 - 1000 grit
- claystone: 1000 grit and finer