3M 61188 947D Series Type 27 Flap Disc, 4-1/2 in Dia, 60 Grit, Medium Grade, 13300 rpm, Orange

3M™ flap disc 947D provides a system for low-pressure grinding, small weld removal, finishing and surface preparation with just one disc. The one-step alternative to bonded wheels and fiber discs, these discs run fast enough for stock removal but provide cushioning with the flaps for a soft finish. Effective for preparing stainless steel for #3 and #4 finishes. 3M™ flap disc 947D features self-fracturing ceramic aluminum oxide abrasive grain with a superior cut rate to aluminum oxide and versatile performance on many metal-types. It is made with an X-weight cotton backing that supports a fast cut for light-duty grinding and finishing. 3M™ flap discs offer an unbeatable system for grinding and blending in one easy step. The construction wears away, exposing fresh mineral to extend disc life and provide consistent cut rates. Great for weld grinding, blending, deburring, rust removal, surface prep and edge grinding on all types of metals.
3M Cubitron coated 947D Type 27 flap disc uses ceramic as the abrasive material and has a diameter of 4 1/2 in. 3M incorporates this ceramic material into the flap disc forming a grit of 60. All abrasive products that rotate or spin, such as the ones in this category, have a maximum speed at which you can run them. This 3M flap disc can be run at a maximum speed of 13300 RPMs. The 3M flap disc uses fiberglass for the backing plate.
Specifications:

Abrasive Type: Coated

Flap Disc Type: Type 27

Specification parameters description:

Abrasive Material:
Values: A/O Aluminum Oxide AO A/Z Alumina Zirconia AZ Alumina Zirconia Alumina zirconia is very dense and can be used under high temperatures for heavy-duty stock removal, wood planing, and grinding of fiberglass and plastics. The abrasive grain is designed to fracture during use so that it maintains sharpness. Aluminum Oxide Aluminum oxide is an artificial abrasive suited for general purpose stock removal and finishing. It is the mostly commonly used abrasive and can be used for most steels and ferrous alloys. Aluminum oxide is slightly softer but tougher than silicon carbide. Aluminum Oxide/Ceramic PSG Ceramic Ceramic is used for aggressive cutting and grinding of stainless steel, titanium, and metal alloys. The abrasive grain is designed to fracture during use so that it maintains sharpness. Ceramic Alumina Ceramic/Alumina Zirconia Ceramic Aluminum Oxide Ceramic Precision-Shaped Grain Diamond Diamond can be either natural or manufactured and is one of the hardest abrasive materials. It is commonly used for grinding and polishing stone and very hard steels, and for sharpening other cutting tools. S/C Silicon Carbide SC Silicon Carbide Silicon carbide is a manufactured material that is extremely hard but brittle. It is commonly used for fast cutting under light pressure, particularly on cast iron, nonferrous metals, and materials such as glass and plastic. Zirconia Zirconium
Grit:
Grit is a measurement of the size of abrasive particles embedded in coated abrasives. The most common standards for grit size are the United States CAMI (Coated Abrasive Manufacturers Institute) and the European FEPA (Federation of European Producers of Abrasives). A smaller grit number means larger particles and a coarser grade, while high number grits are used for finer work. Grit is generally a unitless measure but is sometimes measured in microns.
Maximum RPM:
The maximum rotations per minute (RPM) a product is designed to be used at should be respected for the sake of safety and use life. Maximum RPM is provided for all product listings where applicable and is often printed on the item in the case of discs and wheels. Operating a wheel above its maximum recommended speed can cause a wheel to crack or even shatter.
Flap Backing Weight:
Paper and cloth have a lettering scale for backing weight that measures strength of the material onto which the abrasive is mounted. Paper uses the letters A-F, where A is a lighter weight and most flexible and F represents a rigid, heavier backing. Lighter backings are typically paired with finer abrasive grits, suitable for blending and finishing. Coarser grits used for deburring and stock removal rely on a heavier backing. Cloth uses a lettering system of J, X, and Y for backing weight. J weight (jeans) is the lightest and most flexible, X weight (drills) is more durable and recommended for medium duty work, and Y weight is the toughest and least flexible. Fiber backings are made from chemically-impregnated paper to form a very hard, strong backing material. Fiber is used primarily for sanding discs. Polyester film backing provides high strength with a very thin backing and is used for very fine grits. It is more tear resistant than paper backing and is also waterproof.
Grade:
Grade is a measurement of the size of abrasive particles embedded in coated abrasives. It is a more general measurement of the level of precision, and corresponds roughly to grit. A smaller grit number means larger particles and a coarser grade, while high number grits are used for finer work.
Backing Plate Material:
Flap discs are three dimensional discs consisting of abrasive flaps glued to a backing plate. Fiberglass is the most commonly used backing and is very strong and durable. Reinforced nylon plastic is becoming more common and has the advantage that the backing can be trimmed away to increase usage of the abrasive materials. Non-reinforced nylon backing is only semi-rigid for conformability to work surfaces. Discs can also have a phenolic resin backing, which wears uniformly with the flaps. Metal backings are the safest to use and also the most aggressive, but are the most expensive. The most common metal backing is aluminum, though stamped steel is also used.