Walton & Beckett

The Walton and Beckett graticule is used for counting fibrous dust (e.g. asbestos or glass fibres) and is particularly useful where the majority of fibres to be counted are shorter than 5 micron. The circle is divided into four by two diametrical lines scaled in units of 5 and 3 microns respectively. 3 and 5 microns are the critical measurements of fibre lengths used in fibre counting. Unlike the usual globes of other prticle graticules the Walton and Beckett had a series of shapes to compare objects with. These shapes have been designed for comparison with fibres, especially since they incorporate an aspect ratio of 3:1 or 5:1 essential for such analysis.

Reference: W.H.Walton and S.T.Beckett, Occupational Hygiene. Vol.20 pp 19-23/. “A Microscope Eyepiece for the Evaluation of Fibrous Dusts.”
Walton & Beckett pattern, 3:1 ratio : G22 
Walton & Beckett pattern 5:1 ratio : G24 
Walton & Beckett pattern, 1996 design : G25

Graticules Optics now offer 20.4mm (Olympus), 24.5mm (Leica) and 25mm (Nikon, Meiji) diameter reticles at standard prices – no need to pay a premium price for a special size

Key Features

Eyepiece reticle with Walton & Beckett 3:1 pattern for asbestos analysis

Walton & Beckett for asbestos fibre analysis, 3:1 ratio. See notes on previous screen and page 15 of our eyepiece reticles catalogue for information on calibration factor. Standard versions have a calibration factor of 4 for use with 40x objective magnifications.

Key Features

Eyepiece reticle with Walton & Beckett 5:1 pattern for asbestos analysis

Walton & Beckett for asbestos fibre analysis, 5:1 ratio. See notes on previous screen and page 15 of our eyepiece reticles catalogue for information on calibration factor. Standard versions have a calibration factor of 4 for use with 40x objective magnifications.

Key Features

Eyepiece reticle with Walton & Beckett 1996 pattern for asbestos analysis

Walton & Beckett for asbestos fibre analysis, 3:1 ratio. See notes on previous screen and page 15 of our eyepiece reticles catalogue for information on calibration factor. Standard versions have a calibration factor of 4 for use with 40x objective magnifications.