Actually , there is more than onesandpapernumbering system . The most common system used in the U.S. measures the grits of emery paper in an ascending fiat , with the finest grit acquire the highest number and coarser grit having abject numeral . In this system , 16 - grit is one of the coarsest grades of emery paper , while 3,000 - grit is one of the fine . This organization is have it away as CAMI , as it was developed by the Coated Abrasives Manufacturers ' Institute , and was approve by the American National Standards Institute .
In Europe , the Federation of European Producers of Abrasives ( FEPA ) has its own system for grading gumption of sandpaper . Again , they start from coarse to fine , with the addition of the letter P before the grit number . Until around P240 , the two arrangement are approximately in sync , with 60 ( CAMI ) equaling P60 ( FEPA ) , 180 ( CAMI ) like to P180 ( FEPA ) and 240 ( CAMI ) equaling around P240 ( FEPA ) , but then the two begin to diverge . The 320 - gumption ( CAMI ) is about equal to P400 , 440 - gritstone ( CAMI ) is P600 , 600 - sand ( CAMI ) is P1200 ( braggy difference ! ) and 800 - sand ( CAMI ) is the eq of P1500 . It ’s authoritative to keep in mind which system is being used by your sandpaper producer and the teaching you have for how to sandpaper something . Otherwise , you might end up using the wrong grad of emery paper on your project and ruining it .
In addition to the U.S. and European scheme , there is the Japanese system . Their 150 - sand is equivalent to the 100 - grit CAMI , the 1,000 - moxie measures up to the 700 - grit CAMI and the 10,000 - grit is the same as the 2,000 - gritstone CAMI . In the micrometer system , the higher the numeral , the coarser the grit , unlike the other three systems mentioned . One micron is a millionth of a metre , so 535 - micrometer sandpaper correspond to the vulgar 36 - grit CAMI sandpaper , and 116 - micron emery paper is similar to 120 - gritstone CAMI sandpaper . The 3 - micrometer sandpaper is equivalent to 1,500 - sand CAMI emery paper , and 1 - micrometer sandpaper is like 2,000 - grit CAMI sandpaper .
