Slide rules HOME page COLLECTION SPECIALISED RULES
Make Easyr Hydraulic Slide Rule, UK
Model None given. Made by the Easyr Slide Rule Co, Birmingham
Notes
1. This is a special rule produced for calculating velocities in pipes for given sizes and gradients.
2. Its binding gives the impression of being red leather.
3. The rule allowed the use of two different formulae; Kutter and Crimp & Bruges. Instructions in its use are given here.

Rule closed
9904-hydraul01.jpg (13495 bytes)

Gilt embossed name
9904-hydraul02.jpg (16251 bytes)

Rule opened
9904-hydraul03.jpg (24526 bytes)

Detail
Circular pipes
9904-hydraul05.jpg (16727 bytes)

Detail
Egg-shaped sewers
9904-hydraul06.jpg (14985 bytes)

Detail
Pipe dimensions
9904-hydraul07.jpg (15938 bytes)

Detail -scales
9904-hydraul04.jpg (56793 bytes)

Alternative scale
9904-hydraul08.jpg (24753 bytes)
Manufacturing date I would guess around 1950
Length 16 cm
Material Cardboard. When closed it gives the appearance of a small Moroccan leather bound book with marbled edges to the pages.
Scales Special scales for sewerage pipes running completely or partially full.
Cursor None
Hair lines  
Documentation None
Condition Very good.