Technical Resources

Abrasive Grains

Aluminum Oxide - Used for a broad range of applications, Aluminum Oxide is the most commonly used abrasive for general purpose work. Ferrous and non-ferrous metals, wood and solid surfaces.

Zirconia - Used for heavy material removal on all types of metals, Zirconia Alumina is a long-life premium abrasive that delivers aggressive cutting action while grit particles continually produce new sharp points. Great for titanium, hard steel and stainless.

Ceramic  - While producing outstanding results, Ceramic is a long-life premium abrasive, used for medium to heavy material removal on aerospace alloys, aluminum, carbon steels, nickel alloys, cast iron, forgings, and some stainless steels.

Silicon Carbide -  Used to obtain excellent results on concrete, stone, glass, plastics and very hard materials like titanium. A brittle self-sharpening grain.

Compact Grain - has a uniform scratch pattern, it is very strong, lasts a long time. It re-sharpens itself as it’s used.

Surface Conditioning color codes:

Coarse/Brown: For de-burring and heavy surface material removal

Medium/Maroon: For moderate to light cleaning, blending and surface material removal

Very Fine/ Blue: For removing fine scratch marks and lines, final finishing, polishing and preparing surfaces for painting

Super Fine/Gray: For finishing, buffing and fine polishing

Grinding wheel hardness
Hardness is rated from A-Z with 'A' being the weakest bond and 'Z' being the strongest.  A weak bond is preferred for grinding harder materials while a stronger bond is desired for softer materials.  A typical weak bond for steel would be in the 'F, G or H' range.  A medium hardness would be in the 'I, J or K' range. And stronger bonds in the 'L, M, or O' range.  Hardness is dependent on the grit type, the material being ground, the amount of stock removed, and a number of other factors.

Hardness grades are typically linear: If you increase the hardness by one letter grade (An H to and I for instance) it could give you double the wheel life.  Many people mistakenly believe that such a move (from an H to an I) would only be marginal -- Don't be misled here: A move of just one or two hardness grades could have a dramatic effect on your process!

Flap Discs Info
1. Flap Discs both grind and finish in one step. Therefore, the traditional two-step process of using a grinding wheel and resin fiber discs is made obsolete.  Always go one level coarser with a flap disc as opposed to a resin fiber disc.
2. The right speed increases the service life of a flap disc by up to 100% - essentially doubling the life. The optimal speed for flap discs is between 5000-8000 RPMs, depending on their size and the material surface. Used at the optimum speed, they achieve their optimum grinding capacity and service life.  This can be accomplished by using a variable speed angle grinder.
3.The flat shape (Type 27) is designed to grind edges and flat surfaces with a working angle of 0° -15° degrees.
4. The angled shape (Type 29) is designed for spot grinding.
    Ex: a weld seam with an ideal working angle of 15°-25° degrees.
5. General recommendations in the selection of grits:                
    •40 grit  coarse  for extra heavy deburring or grinding
    •60 to 80 grit  medium  for medium deburring and finishing
    •120 grit   fine  for cleaning and final finishing
6. Coated abrasive material types for metalworking:
    •Good - Aluminum oxide is a general purpose grain and suitable for most general purpose applications.  It is specified for use on wood and most metals.
    •Better - Zirconia grains are both sharp and durable, providing fast stock removal and longer life. They are used to greatest advantage in coarse grits on heavy-duty   metalworking stock removal applications.
    •Best - Ceramic grain series are special products for aggressive and cool grinding. These abrasives ensure faster grinding while at the same instance offering better surface quality and excellent stock removal rates. The cool grinding properties of ceramic ensure an extension of the service life and prevents surface discoloration. Ceramics are specifically applicable for grinding high alloyed steels, titanium, nickel alloys and all extremely hard materials.

We make our flap discs right in our Willmar, MN plant. We use premium grade sanding material from VSM, we use a high quality glue and our backing plates are the best available. We offer more flaps than our competitors! Try our flap discs and we guarantee you will see the difference.

 Sanding Wood

•     On soft woods such as Pine, Aspen or Alder, sand first with #120 and finish with #220. On hardwoods such as Oak, Maple, Birch or Parawood, sand first with #120 and finish no finer than #180.

•    On hard woods such as maple or birch, start with a #120 grit paper and finish with a #150 grit paper to keep the grain open and receptive to stain. Finish the final sanding with a finer grit sandpaper such as #220