Diamond Tool Tips
Diamond Tools 101
In short summarized fashion, we answer a couple of really simple questions that's got really long answers.
What is a Diamond Tool?
A diamond tool is any tool that uses the invulnerability of diamonds to wear out other softer or weaker materials, such as stone or concrete, to yield the results you want, whether it is to sculpt, to cut, or to polish.
A diamond tool, be it a coring bit or blade, is usually made of steel, and will consist of a workable rim or tip made of manufactured diamonds, which are embedded in a metal matrix.
Metal Matrix Powder
The metal matrix can either be distributed continuously or clustered into segments separated by slots, giving the blade “teeth”.
Segmented rims have slots (or gullets) cut into the blade core separating each diamond segment. These slots provide additional cooling by allowing water or air to flow between the segments during cutting.
A Slotted Diamond Blade
The slots also allow the blade to flex while cutting and to expand without warping when the blade becomes heated during use.
Diamond cutting segments or rims consist of manufactured diamonds dispersed throughout a metal powder. When this mixture is heated, the diamonds are bonded into a solid matrix.
Metal Matrix Bond
Some manufacturers concentrate the diamonds in the half of the matrix closest to the outside edge. That’s why some blades cut better initially than they do after they’re worn halfway down.
One reason for distributing the diamonds this way is because segment loss usually occurs after the blade has been about 75% used. If a segment is no longer functioning, all the diamonds in that busted segment goes to waste and will never get used. To prevent wastage while considering the unavoidable impending segment loss, manufacturers are usually less inclined to distribute the diamonds uniformly throughout the matrix.
There are many ways of attaching diamond segments or matrixes to the steel core (or blank). It may be laser welded, vacuum brazed, or heat pressed. Of all these methods, laser welding is the most durable, and consequently, the most expensive to manufacture. Vacuum brazing, is also known as soldering, as the diamonds are attached to the blank tool via soldering.
Soldering is the most common attachment method for wet tools because wet tools have the luxury of working while being water-cooled.
Dry tools are prone to overheating the soldering, resulting in shortened tool lifespan.
A laser weld, on the other hand, is the strongest attachment method. Although most manufacturers laser weld on only one side, not both sides, one manufacturer reports that laser welding on both sides reduces segment loss to less than 5%.
A laser welded diamond tool, whether segmented or continuous, will always have wider matrixes than the core on which they are mounted. This extra width allows the cutting edge to penetrate through the material. It provides space to allow coolant water and debris to escape. It also minimizes wearon either sides of the core.
To achieve the extra width, some manufacturers use steel pads under the segments. If the matrix is worn and these steel pads are exposed, the tool would seize to function.
Other, more expensive tools have the diamond-impregnated matrix through the full segment thickness, so the tool will continue to work effectively until there is literally no diamonds left.
The operator pushes the rotating blade into the material to be cut. Upon contact, the diamonds begins to finely grind through the masonry. And equally, the masonry will begin wearing away the diamond impregnated matrix at the tool’s cutting edge.
The exposed diamonds grind the masonry into fine powder, themselves cracking, fracturing, and heating as they grind. Harder masonry causes the diamonds to fracture faster. Hard or abrasive masonry also causes the metal powder matrix to wear faster.
For a diamond blade to work efficiently, the diamond quality, type, and size must be matched to the saw speed and masonry material. Also, the wearing rate of the metal powder matrix must match the masonry being cut.
Blades used for cutting hard brick or stone require a softer metal matrix. The softer matrix wears faster, replacing worn-out diamonds fast enough for the blade to keep cutting. Blades for cutting a softer material such as lightweight concrete block require a stronger, harder matrix to resist abrasion and fragmentation, and will hold the diamonds longer. The harder matrix prevents the diamonds from being lost before they have exhausted their entire useful life.
- April 2011
Choosing a Diamond Tool
Whether you are looking for drilling and coring or blades for cutting, choosing a diamond tool is no easy feat because of the sheer variety of blades available and the wide range of prices they sell for.
Let us take diamond blades for example. The masonry industry has no standard method of grading blades, making it hard to compare blades from different manufacturers.
The best advice is to match the blade to the material you’ll be cutting, the amount of cutting, and finally, the saw’s physical dimensions.
It is not feasible to buy a blade with a lower initial cost if it won’t cut fast enough or last long enough to get the job done. Think in terms of cost per cut (feet).
While hand grinder blades are relatively inexpensive and do last a reasonable length of time to last through a job or two, bridge saw blades do not come cheap. 14-inch-diameter blades sell for anywhere between $200 to $600, granted that you already have an $18,000 bridge saw platform in your workshop.
One of these mean puppies
Choosing the most economical blade for your needs isn’t easy. Before setting out to buy one, you must answer several questions:
- What is the saw’s speed rating?
- Is wet or dry cutting required?
- What type(s) of masonry do you plan to cut?
- How much material do you have to cut?
- How smooth a cut is necessary?
Blades generally have a designated maximum rpm.
Wet cutting is cooled by water whereas dry cutting is air cooled.
Hardness of different materials will vary. Most blades are material-specific and excel at cutting a particular type of stone.
Stone slabs are usually a set size, but some jobs require more cutting than others.
Some blades offer faster cutting, but the cuts are jagged at best. While other blades are slow cutters, but can offer a much smoother cut.
Getting a handle on these factors will help you choose an economical blade.
Cutting Different Materials
Most diamond tools are designed to work with a specific material. Using incorrect tooling will result in reduced tool life span, increased chance of tool malfunction, and can be hazardous to the user.
To maximize cutting speed and blade life, match the blade as closely as possible to the material. If a job requires cutting more than one masonry material, base your tool choice on the material that is cut the most often or the material for which the best performance is of the utmost most importance.
Multi-purpose blades, though not as efficient on every material, can still cut effectively and save you time from changing blades. For larger jobs, use two saws, each equipped with a different blade to match the masonry materials.
As for how much you should pay, it will depend heavily on what exactly you are doing with the tools
For small jobs or occasional fabricating, cutting and coring with a lower-priced diamond tool might be the best choice. As for medium to large projects, initial tool cost is not as important as cost versus durability. Or more specifically, cost per cut.
A more expensive tool or blade might be able to provide faster cuts and a longer life than a cheaper one when it comes to bigger jobs. Some jobs may even warrant a repertoire of blades for the best results.
Like this, colorful isn't it?
Hard, brittle materials like stone and hard bricks have the tendency to chip when they are being cut. To minimize chipping, especially on architectural jobs, use a diamond tool that has a continuous rim. It will less aggressive, but it will provide a smoother cut than a segmented tool.
The value of a diamond tool is hard to compare to other types of tools because it is very uncommon. Most hardware stores don't have a diamond tools isle. The hefty price tag will throw off inexperienced buyers. Sending inexperienced workers to buy a diamond blade will almost always results in the purchase of a blade with the lowest initial cost, and consequently, the worst durability and cut quality. To put things in perspective, carpentry saw blades usually sell for $10 a piece compared to a mid-range $400 diamond blade for masonry. Purchasing masonry saw blades is important; don’t delegate the task to the newest employee.
-April 2011
