Blade Basics

Given the variety of diamond blades available on the market, choosing the right one for the job can be a daunting task for your customers, but you can help make the process easier by arming yourself and your staff with the right information.

In order to effectively serve your customers, it’s important to display your blade inventory in a simple and straightforward way.

To start with, don’t display too many products. You don’t want to confuse the customer. First determine your primary customer base and what blades would best serve them and then go to work on making sure your customers are aware of what blades you have to offer.

While it can go a long way toward assisting your customers with blade selection, an effective display is still only half the battle. Your counter staff really needs to be well educated to ensure your customers leave your store with the right blade for their job.

Before an employee can make the right recommendation to your customers, he or she needs to understand the basics of diamond blades.

Between a rock and a hard place

While it seems counter intuitive, the general rule of thumb for blade selection is simple: hard blades cut soft materials and soft blades cut hard materials.

To understand this, it is first necessary to understand fundamental blade composition and how a blade works.

A diamond blade is simply a circular steel disc with a diamond bearing edge, says Thom Fisher with Diamond Products. The edge or rim can have either a segmented, continuous or serrated rim configuration.

Diamond segments or rims are made up of a mixture of diamonds and metal powders, explains Fisher. The diamonds used in blades are synthetic and are carefully selected for their shape, quality, friability and size. These are then mixed with a powder consisting of metals such as cobalt, iron, tungsten, carbide, copper and other materials. This mixture is then molded into shape and then heated under pressure to form a solid metal part called the bond or matrix.

Contrary to popular belief, diamond blades do not actually “cut,” they grind. Exposed diamond crystals in the bond or matrix do the grinding work. As the blade rotates through the material, the exposed surface diamonds grind the material being cut into
a fine powder.

After several thousand passes through the material being cut, the exposed diamonds begin to crack and fracture. The matrix holding the diamond also begins to wear away. Eventually, the diamond completely breaks up and its fragments are swept away with the material that it is grinding. As the old diamonds are worn down, they are replaced by new ones and the process continues until the blade is worn out.

Knowing this, it makes sense that harder aggregates, such as flint, chert, trap rock and basalt, will break down diamond crystals faster, so it’s necessary to use a softer bond to expose new diamonds. Likewise, softer aggregates, such as limestone, do not break down the diamonds as fast, so it requires a harder bond to hold the diamonds in place in order to use their full potential.

“The application of a diamond blade to the material cut is a relationship that matches the abrasion resistance of the diamond segment to the abrasiveness of the material cut,” explains Gabriel Uriegas with Saint-Gobain Abrasives, makers of Norton and Pro-Cut blades. “Simply stated, hard blades for soft materials and soft blades for hard materials.”

Factors affecting performance

According to Fisher, how a blade performs has much to do with what is being cut, so it’s important to ask your customer what they plan to do with your blades. He points to some of the factors affecting performance:

Compressive strength — Concrete can vary greatly in compressive strength, which is measured in pounds per square in. (psi). Most concrete roads are approximately 4,000 to 6,000 psi, while typical patios and sidewalks are about 3,000 psi.