We’re working on a FAQ and other resources — coming soon!
The KMG was intentionally designed so that the motor was not an integral part of the machine which allows for unlimited choices in how the grinder is powered. This allows you the use just about any type of motor and it also allows to set the grinder up with different speeds by changing the pulley ratio between the motor and grinder. We prefer to drive the KMG with pulleys and a a belt to maximize the versatility, however you can also direct drive with a motor coupling of your choice. Typical motor sizes for the KMG can be from 1-1/2 to 5 hp.
We always recommend a grinder package such as the KMG-8 or KMG-10 that includes both, a contact wheel, and the platen attachment. These 2 attachments will be used constantly in your shop. The 8″ and 10″ wheel are equally popular and purchased on personal preference. A work rest is included.
With the standard 4″ drive wheel, the abrasive belt speed is easily calculated as follows:
Belt speed (ft/min) = RPM (example: 100rpm= 100ft/min, 3500 rpm= 3500ft/min)
The KMG Grinders are proudly built from unplated and unpainted steel. If you wish, you can customize the grinder by plating or painting the exposed metal surfaces, but in our shop, we care for the grinders simply with a coat of light oil and a Scotch Brite pad to scour away dirt and small scratches.
8” vs 10” wheel:
This is a great question and is usually decided by personal preference. Since the belt speed is the same regardless of the size of the contact wheel, there is no performance differences between the sizes. The only difference is the shape of the hollow grind caused by the wheel. Because the 10” has a bigger radius, the hollow grind is more shallow and taller than what an 8” wheel would produce. The 10” wheel is much more popular. However, there are many customers who prefer the 8” wheel for it’s smaller size, lower cost, and deeper hollow grind.
3 speed –vs- Variable speed:
The KMG was specifically designed so that the motor was not an integral part of the grinder. This allows for unlimited choices on how it might be powered. Simply spinning the drive shaft makes the grinder run.
The step pulley system allows 3 speed choices, fast, med and slow. The 4”, 3” 2” pulley is used because the centerline distance between the motor shaft and grinder drive shaft is the same for each belt position. This eliminates the need to re-adjust the motor position for each speed change. You simply roll the belt from on groove, to the next smaller size by hand, like a derailleur on a bicycle. Speed changes are done in a few seconds without tools. The grinding belt speeds produced are approximately 3800, 1800, and 900 feet/minute. Through research, these speeds are all very practical and usable speeds for tasks like custom knife making.
Variable basically allows an infinite selection of speed from 0-100%. It can be changed on the fly without stopping and allows the user to adjust for more grinding control and precision based on personal preference and feel. Comparing to the 3 speed set-up, the highest belt speed can be about 10% faster due to selections in the motor’s speed control (VFD), or about 4200 feet/minute. The speed range is infinite from full speed down to zero.
Install and Set Up Instructions and Diagrams:
Installation instructions Forward/Stop/Reverse switch for our variable speed controllers