This assembly allows the 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 inch (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).

3M 77197, Scotch-Brite™ Roloc™ Deburr and Finish PRO Unitized Wheel,TR, 3 in x 1/8 in x NH, 8C CRS+, 7100109130, 40/box
3M™ 17379, Versaflo™ Length Adjusting Breathing Tube BT-30, 7100009685, 1 EA/Case
3M™ 72010, Replacement Filter Kit 523-01-29, 7000056891, 1 EA/Case
3M 24049, Wetordry Cloth Disc 281W, P1000 YF-weight, 8 in x NH, Die 800JM, 7000045052
3M™ 72787, Calibration Kit 529-04-48, Large, 7000052154, 1 EA/Case
Dynabrade 58504 3-1/4" W x 5" L Dynabug II Orbital Sander, Self-Generated Vacuum, .15 HP, 10,000 RPM, 3/32" Orbit
Dynabrade 40320 Dynafile II Abrasive Belt Tool
3M™ 72013, Adapter 529-04-50, 110-120 VAC, 7000131705, 1 EA/Case
3M 87449 Silver Depressed Center Grinding Wheel, T27 Quick Change, 9 in x 1/4 in x 5/8-11 Center Hub Thread, 7010409732, 20 per case
Dynabrade 11486 Dynabelter Accu-Grinder Abrasive Belt Tool, Heavy-Duty
3M 71361, 641WY 1/4" X 24", 1200 Mesh Diamond Cloth Belt, 7010534916
3M 13372, Scotch-Brite Star, 3 in A CRS LS, 7000120967
3M 89633, Fibre Disc 787C, TN Quick Change, 4-1/2 in 36+, 7100099291
3M™ 53797, Flexible Diamond Belt 6451J, 1/2" Dia x 18" L, M125 Micron, Type G, Pattern B2, 7010509272
3M 22405, Roloc Disc 361F, P100 YF-weight, TR, 3 in, Die R300V, 7000045102
3M 95723, Scotch Automotive Cloth Tape 06980, Olive, 50.8 mm x 18.2 m, 7010312582
3M 28764, Cubitron II Cut and Grind Wheel, Type 27 Quick Change, 6 in x 1/8 in x 5/8"-11, 7100019069, 20 per case
3M 22395, Roloc Disc 361F, 60 YF-weight, TR, 3 in, Die R300V, 7000045098 
