This assembly allows 3M Disc Pad Face Plate to be easily changed without removing the disc pad hub, allowing the operator to use a single tool for multiple applications from heavy grinding to finishing a workpiece.
Some face plates have ribbing on the bottom face. Ribbed face plates provide additional force when needed for optimal fracturing of the abrasive mineral. By reducing the area of contact, or pressure per square foot (PSI), ribbed face plates increase the grinding pressure of the abrasive with the same amount of operator effort, and extend disc life when dulling is a problem.
Choose a plate with the level of firmness needed for the application?a lighter density face plate for lighter weight grinding applications, and a harder density face plate for more heavyweight grinding applications. Using the correct face plate for the application ensures that the abrasive mineral will fracture as it should, maximizing the life of the abrasive. The plate comes in one of four different colors that indicate the density so the correct plate can be easily identified in the workroom: red = extra hard (for heavy grinding with the coarsest grades), black = hard (for heavy metal removal, large welds, etc.), gray = medium (for general purpose grinding and finishing), and white = soft (for finishing operations on flat or contoured surfaces).

Dynabrade 53270 7" (180 mm) Dia. Right-Angle Disc Sander
3M 22397, Roloc Disc 361F, 60 YF-weight, TR, 1-1/2 in x NH, 7000045097
Insize 1179-300WL, WIRELESS DIGITAL RTJ RING GROOVE CALIPER, 10-300mm/0.4-12", 0.01mm/0.0005", 6940561961010
Dynabrade 51622 .1 hp Straight-Line Pencil Grinder, Central Vacuum, 35,000 RPM, 3mm Collet
3M 20360, Scotch-Weld Epoxy Adhesive 2216, Gray, Part B, 5 Gallon Drum (Pail), 7000046360
3M 76630, Roloc Disc 777F, 50 YF-weight, TR, 2 in, Die R200P, 7000045627
3M 06839, Booth Coating, 1 Galllon, 7000028421
Dynabrade 95843 Dynabrade Air Lube 10W/NR, 1 Gallon
3M 94738, Cubitron ll Cloth Belt 947A, 120+ X-weight, 6 in x 48 in, Film-lok, Single-flex, 7010299911, 20 per case
Dynabrade 79379 6" Dia. x 180 Grit A/O Hook Multi-Hole Vacuum Film-Backed DynaCut Disc, 100/Box
3M 77559, Cubitron II Hookit Cloth Disc 784F, 77559, 36+ to 120+, 5 in x NH, Die 500X, 7100232738 
