What Is a Diamond Blade Knockout Arbor?
If you have ever installed a diamond blade and noticed a removable inner ring around the center hole, you have seen a diamond blade knockout arbor. This small but important feature allows a blade to fit multiple saw types by adjusting the arbor hole size.
The arbor is the center hole of the blade that mounts onto the saw shaft. Different saws use different arbor sizes, such as 20 mm, 1 inch, or 7/8 inch. A knockout arbor is a pre sized insert built into the blade that can be removed to match the arbor size of your saw.
This design gives contractors more flexibility and reduces the need to stock multiple versions of the same blade.
Why Proper Arbor Fit Is Important
Using the correct arbor size is critical for safety and performance. A blade that does not fit snugly on the saw shaft can wobble during operation. That vibration can cause uneven wear, poor cut quality, and in extreme cases, segment damage or blade failure.
A properly fitted diamond blade knockout arbor ensures:
- Secure blade mounting
- Reduced vibration
- Cleaner cuts
- Extended blade life
- Safer operation
Even a high quality diamond blade will not perform properly if it is not mounted correctly.
How Diamond Blade Knockout Arbors Work
Diamond blade knockout arbors are designed with a removable insert. For example, a blade may come standard with a 20 mm arbor and include a knockout ring that allows it to convert to 1 inch when removed.
To adjust the arbor:
- Confirm your saw’s arbor size.
- Inspect the blade to see if the knockout insert needs to be removed.
- Carefully remove the insert if required.
- Mount the blade securely and tighten according to manufacturer guidelines.
Always verify that the blade sits flush against the mounting flange with no gaps or play.
Common Arbor Sizes in Concrete Cutting
Different saws use different arbor sizes depending on blade diameter and application. Handheld cut off saws commonly use 20 mm or 1 inch arbors, while angle grinders often use 7/8 inch.
Because many contractors operate multiple saw types, knockout arbors make inventory management much easier. Instead of stocking separate blades for each saw size, a single knockout arbor blade can serve multiple machines.
Avoiding Common Mistakes with Knockout Arbors
While knockout arbors are convenient, improper handling can create issues. Common mistakes include:
- Removing the insert when it is not necessary
- Failing to remove the insert when required
- Installing the blade without checking for snug fit
- Using damaged or bent mounting flanges
Before starting any cut, always double check arbor compatibility and blade alignment.
Final Thoughts
Diamond blade knockout arbors may seem like a small detail, but they play a major role in safety, performance, and versatility. A properly fitted blade reduces vibration, improves cut quality, and extends blade life.
When selecting diamond blades, always confirm arbor compatibility with your saw. If you are unsure which blade or arbor configuration is right for your equipment, consulting with a knowledgeable supplier can prevent costly mistakes and downtime.
