Chapter 25: Homemade tools and teaching materials
Quarter-circle scale
If this scale is made with plywood,
use sheet metal to reinforce the upper
corner. The weight should be between
1 and 2 kilograms. It can be made from
scrap metal or a piece of heavy pipe.
Spring scale
This scale is made with a coil spring
inside a bamboo tube. The spring
should be about 30 centimeters
long and squeeze to half its length
with a weight of 15 kilograms.
30 cm
plywood
or sheet
metal
holes about
2 cm apart
weight
wire or cord
metal hook
bent
nail
slot
washer
to mark
weight
bamboo
coil spring
bent
nail
side view
front view
How to make the scales accurate
To mark the scale accurately, you will need some standard weights.
Perhaps you can:
• borrow some weights from a merchant at the market.
• use a merchant’s scales to
make your own weights by
filling bags with sand.
• use 1-kilogram packages or cans of food.
To mark your scale
1. Hang a 1-kilogram weight on it.
2. Balance the movable weight.
3. Mark the spot with a small line and write a “1.”
4. Now add 1 more kilogram at
a time, rebalancing the
weight and making a mark
each time, until you have
6 or 7 marks on the scale.
1
446
A Book for Midwives (2010)