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).

3M 22970, Disc Holder Adapter 9, 5/8-11 External 3/8-24 Internal, 7000046093
Dynabrade 78292 2" Dia. x 6A M Medium Type R Unitized Locking-Type Disc, 25/pack
3M 81729, Disc Pad Face Plate Ribbed, 9 in Hard Black, 7000148244
3M 35827, Hookit Dust Extraction Flexible Sanding Block, 273 mm x 67 mm, 7100256623
Air Turbine Tools 310RSV - 1/4" Router Hand Tool Series with Brake, 30,000RPM, 33434
3M 17094, Versaflo Hood Assembly with Inner Shroud & Premium Head Suspension S-657, 7000002348, 1 EA/Case
3M 65033, Scotch-Brite Diamond Wheel, 645DC 6 in x 1/2 in x 1 in, 7010365574, Box of 3
3M 87266, Scotch-Weld Epoxy Adhesive DP100 Plus, Clear, 200 mL Duo-Pak, 7100069498, 12/case
3M 64421, Two-Component Adhesive Sealant Applicator 400A-2K, 7100010298
3M 33780, 641WY 1/4" X 24", 400 Mesh Diamond Cloth Belt, 7010534915
3M 08367, Urethane Seam Sealer, Black, 310 mL Cartridge, 7000119968, 12 per case
Dynabrade 64404 36" W x 60" L (914 mm W x 1,524 mm L) Metal Capture Downdraft Table, 230 V (AC), Side Exhaust
3M 16583, Accuspray Atomizing Head, Green, 1.3 mm, 7010309279
Dynabrade 95842 Dynabrade Air Lube 10W/NR, 1 Pint
3M 29851, Sanding Screen, 100 Grit, 15 in x NH, 7100160814
3M 28214, Cubitron II Roloc Disc 984F, 60+ YF-weight, TR, 2 in, Die R200P, 7010361116
3M 45714, Cubitron II Hookit Cloth Disc 947A, 120+ X-weight, 3 in x NH, D/F 3HL, Die 300BE, 7100113113 
