Page 461 - NORTON cutting-off and grinding wheels - industrial

TECHNICALINFORMATION
461
TECHNICAL INFORMATION
PARTICLE
SIZE IN
INCHES
PARTICLE
SIZE IN
MICRON
ALUMINIUM OXIDE, GARNET,
SILICON CARBIDE, ZIRCONIA ALUMINA EMERY
GLASS
PAPER GRADING SYSTEMS COMP. GRIT
SYMBOL
POLISHING
PAPER CLOTH
CAMI FEPA
,0000118 0,3 – – – – – –
,0000197 0,5 – – – – – –
,0000394 1,0 – – – – – –
,0000787 2,0 – – – – – –
,000118 3,0 – – – – – –
,000158 4,0 – – – – – –
,000197 5,0 – – – – – –
,000236 6,0 – – – – – –
,00026 6,5 1200 – – – – –
,00035 9,0 – – – – – –
,00036 9,2 1000 – – – – –
,00047 12,0 – – – – – –
,00048 12,2 800 – – 4/0 – –
,00059 15,0 – – – – – –
,00060 15,3 – P1200 – – – –
,00062 16,0 600 – – 3/0 – –
,00071 18,3 – P1000 – – – –
,00077 19,7 500 – – 2/0 – –
,00079 20,0 – – – – – –
,00085 21,8 – P800 – – – –
,00092 23,6 400 – 10/0 0 – –
,00098 25,0 – – – – – –
,00100 27,75 – P600 – – – –
,00112 28,8 360 – – – – –
,00118 30,0 – – – – – –
,00118 30,2 – P500 – – – –
,00137 35,0 – P400 – – – –
,00140 36,0 320 – 9/0 – – –
,001575 40,0 – – – – – –
,00158 40,5 – P360 – – – –
,00172 44,0 280 – 8/0 1 – –
,00177 45,0 – – – – – –
,00180 46,2 – P320 – – – –
,00197 50,0 – – – – – –
ABRASIVE GRAIN SIZE
After the crude abrasives have been crushed, the
grains are separated (graded) into standard particle
sizes using screens carefully made from silk
threads of exact size and number per square inch to
ensure extreme accuracy. The grit number (mesh
number) appearing on the coated abrasive backing
represents the number of openings per linear inch
in the final screen. Grits 240 and finer, called flours,
are graded by hydraulic separators, air classifiers
and levigating tanks.
The European standard of grit sizes is the FEPA
grading system. All FEPA grit sizes are preceded
with the letter ‘P’, i.e. P180 etc.
In the USA a different grading system called CAMI
is used. This chart provides a comparison between
FEPA and CAMI grades and also shows average
particle sizes in microns and inches.
Additionally, some products produced for the
woodworking and floor sanding markets are
identified with a ‘grit symbol’. Although use of this
symbol is infrequent, the backing of these products
contain both the mesh number and the grit symbol.