Contents of the Post
In this post, we describe the different types of diamond saw blades, why they become dull during use, and how they can be resharpened.
Introduction
Most people who have ever worked with a sawing machine are familiar with the problem: the saw cuts very slowly, and cutting through a stone takes a very long time. It is often assumed that there is a defect in the machine – however, in most cases, a dull saw blade is the cause.
Why do diamond saw blades become dull?
Diamond saw blades cut by protruding diamonds abrading material. This is not a classic sawing process like with wood, where geometrically defined teeth cut. Rather, it is a grinding process with a geometrically undefined tooth shape, where each protruding diamond acts as a "tooth."
For a diamond saw blade to cut, the diamonds must protrude from the bonding material. If this is not the case, the blade merely slides over the material to be cut without effectively cutting.
Types of Diamond Saw Blades
The diamonds are fixed in a bonding material. Depending on the type of this bond, different types of diamond saw blades are distinguished:
- Saw blades with mechanical bonding
- Saw blades with metallic bonding
- Saw blades with ceramic bonding
- Saw blades with plastic bonding
In the lapidary field, the first two types are usually used.
Saw blades with mechanical bonding
With saw blades that have mechanical bonding, the diamond grit is mechanically fixed to the carrier – usually a steel sheet. For this purpose, special grooves are made in the sheet, into which the diamonds are inserted. Then, the grooves are pressed together, securely holding the diamonds.
Saw blades with metallic bonding
Saw blades with metallic bonding are also known as sintered saw blades. Depending on the composition of the metal alloy, there are softer and harder bonds.
Rule of thumb:
- Soft material → hard metal bond
- Hard material → soft metal bond
This allows these saw blades to be precisely matched to specific materials. For this reason, they often cut certain types of material particularly well. A common metal alloy is, for example, bronze bonding.
How are diamond saw blades sharpened?
Basically, there are two ways to resharpen a diamond saw blade:
- while installed
- dismounted on a special machine
In practice, sharpening while installed is usually applied. For this, a so-called dressing stick is used.
Dressing sticks
Dressing sticks are made of different materials, for example:
- Aluminum oxide
- Silicon carbide
- Dressing sticks with special resin bonding
The task of the dressing stick is always the same: The bonding material is abraded so that new, "fresh" diamonds are exposed.
The Sharpening Process
The sharpening process works best in dry operation. If this is not possible, sharpening can also be done in wet operation.
For sharpening, cut into the dressing stick several times. Some experts recommend switching off the machine while cutting into it and letting the saw blade run out in the dressing stick.
Depending on the wear of the saw blade, this process must be repeated several times.
How to recognize a sharp saw blade?
- A hissing sound is produced when cutting.
- The sawing process takes significantly less time.
- Significantly less pressure is required.
Important Notes
If a saw blade no longer cuts well, you should never work with increased pressure. This often leads to the blade no longer cutting straight but running curvilinearly. In addition, the service life of the saw blade is significantly shortened.
Safety Notice
Always wear personal protective equipment (PPE), especially safety glasses and a dust mask, when sharpening.
This article serves merely as support and does not replace an original operating manual. No liability is accepted for damages arising from the application of these instructions.
