Why Does a Thickness 1.0mm Carbide Slitting Saw Measure Only About 0.9mm? Understanding Tapered Side Clearance
One of our customers recently ordered a custom solid carbide slitting saw with the following specifications:
- Diameter: 100 mm
- Thickness: 1.0 mm
- Material: Solid Carbide
After receiving the tool, the customer measured the blade body using a caliper and immediately contacted us:
“The thickness is only about 0.9 mm. The blade is undersized by nearly 0.1 mm.”
At first glance, this may appear to be a manufacturing error. However, after reviewing the measurement method, we found that the customer had measured the center portion of the blade body rather than the cutting edge.
The tool was actually manufactured exactly according to specification.
The difference came from a common but often misunderstood design feature known as Tapered Side Clearance.
What Is Tapered Side Clearance?
Most high-quality solid carbide slitting saws are designed with tapered side clearance.
Instead of maintaining a constant thickness from the cutting edge to the arbor hole, the blade body gradually becomes thinner toward the center.
The cutting teeth remain at the nominal thickness, while the body behind the teeth is relieved.
As a result:
- Tooth thickness = 1.0 mm
- Blade body thickness may be approximately 0.9 mm
- Both dimensions can be completely correct
Therefore, the nominal thickness of a slitting saw should always be measured at the cutting edge, not at the center of the blade body.
Why Is Tapered Side Clearance Used?
Reduced Friction
When cutting deep slots, the blade body can rub against the side walls of the workpiece.
A relieved body minimizes contact and reduces cutting resistance.
Prevents Blade Binding
Without side clearance, friction increases rapidly during slotting operations.
This can cause:
- Blade binding
- Increased heat generation
- Poor surface finish
- Premature tool failure
Tapered side clearance helps maintain smooth cutting performance.
Better Slot Quality
Reduced side contact leads to:
- Improved dimensional stability
- Better surface finish
- Lower vibration
- Longer tool life
How Should Slitting Saw Thickness Be Measured?
This is one of the most common misunderstandings among users.
Incorrect method:
- Measuring the blade body near the center hole
- Measuring the relieved section
Correct method:
- Measure across the cutting teeth
- Measure at the outer diameter where cutting occurs
The specified thickness of a carbide slitting saw always refers to the cutting edge thickness.
Can a Carbide Slitting Saw Be Reground?
One major advantage of solid carbide slitting saws is that they can be reground and reused multiple times.
However, when tapered side clearance is present, repeated grinding affects the effective cutting thickness.
As the blade diameter decreases during regrinding:
- The cutting position moves inward
- The body becomes progressively thinner
- Slot width may change
For applications requiring high precision slot widths, excessive regrinding is not recommended.
Custom Side Clearance Options
Depending on customer requirements, carbide slitting saws can be manufactured with:
Double-Sided Tapered Side Clearance (Standard)
- Balanced cutting forces
- Best overall performance
Single-Sided Tapered Side Clearance
- Special cutting applications
- Direction-specific requirements
Parallel Sides (No Side Clearance)
- Uniform thickness from edge to center
- Suitable for specific applications
- Higher risk of friction and blade binding
Conclusion
If your 1.0 mm carbide slitting saw measures only 0.9 mm at the blade body, it does not necessarily mean the tool is undersized.
In many cases, the difference is caused by a tapered side clearance design, which is intentionally engineered to reduce friction, improve cutting performance, and prevent blade binding.
Always measure thickness at the cutting teeth, not at the relieved body section.
Understanding this design feature can help avoid unnecessary concerns and ensure the tool is evaluated correctly.