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).

Dynabrade 11477 Dynabelter Abrasive Belt Tool, Heavy-Duty
Norton 66261199696 - 3" X 1/4" X 1/4" Vortex Rapid Blend Unified Wheel, 7AM U2305, 40 Each
3M 33349, 641WY 1/4" X 24", 220 Mesh Diamond Cloth Belt, 7010534919
3M 16151, PTFE Glass Cloth Tape 5451, Brown, 3/4 in x 36 yd, 5.6 mil, 7000050135
Dynabrade 90873 2" Dia. Medium NWN DynaBrite Locking-Type Disc, 25/pack
Dynabrade 51750 .1 hp Straight-Line Extension Pencil Grinder, Rear Exhaust, 60,000 RPM, 1/8" Collet
3M 22395, Roloc Disc 361F, 60 YF-weight, TR, 3 in, Die R300V, 7000045098
3M 53914, Performance Plus Duct Tape 8979N Nuclear Red, 48 mm x 54.8 m 12.1 mil, 7000049014, 24/ case
3M 71361, 641WY 1/4" X 24", 1200 Mesh Diamond Cloth Belt, 7010534916
3M 40118, High Strength Small Hole Repair, All-in-One Applicator Tool, SHR-3-AIO, 7100203787 
