Arbor, Kerf, Blade Diameter, and Tooth Count Explained
Share
Arbor, Kerf, Blade Diameter, and Tooth Count Explained
A saw blade must match the saw as a system. Diameter alone is not enough. Check the arbor hole, kerf, blade-plate thickness, maximum RPM, rotation direction, tooth design, intended material, and every guard or riving-knife restriction in the manual.
| Term | Plain meaning | Why it matters |
|---|---|---|
| Arbor | Shaft that supports and turns the blade | Mounting fit and secure rotation |
| Arbor size | Blade-hole/interface dimension | Must match the approved saw mounting system |
| Kerf | Width of material removed by the cut | Cut-line placement and riving-knife compatibility |
| Plate thickness | Thickness of the blade body | Can differ from kerf |
| Blade diameter | Overall blade size | Guard, depth, speed, and saw capacity |
| Tooth count / TPI | Number/density of teeth | Material, feed, finish, and cut type |
Arbor
The arbor is the shaft that supports and turns a saw blade. The blade's arbor hole must fit the saw's arbor or manufacturer-approved mounting system.
An arbor lock is a blade-change aid used exactly as the manual directs after power is removed. It is not a brake and should not be engaged while the blade is moving.
Arbor size
Arbor size describes the mounting interface. The blade can also use a shaped hole, knockout, bushing, flange, or model-specific system.
Do not improvise washers, bushings, or adapters. A loose, off-center, or incorrectly clamped blade can wobble, contact the guard, damage the saw, or fail.
Kerf
Kerf is the width of the slot removed by the blade. It is not necessarily the same as the thickness of the steel plate because the teeth can project wider than the plate.
Kerf affects:
- Material lost in the cut
- Which side of the line becomes the finished piece
- Feed behavior and cutting load
- Compatibility with a riving knife or splitter
On a table saw, the blade kerf may need to be wider than the riving knife while the blade plate remains thinner. Bosch's table-saw manual gives both relationships because a mismatched thin-kerf blade can bind against the riving knife or leave the knife too thick for the cut.
Common mix-up: Thinner kerf is not automatically better. Compatibility with the saw's safety system comes first.
Blade-plate thickness
Blade-plate thickness is the thickness of the main blade body. Keep it separate from kerf. A product page that lists only one dimension may not provide enough information for a riving-knife check.
Blade diameter
Blade diameter is the full diameter of the blade. Use only the diameter or approved range stated by the saw manufacturer. A larger blade can contact the guard or housing and expose more tooth than the system is designed to control.
Also verify the blade's maximum RPM. The blade's rating must meet the saw's requirements. Never mount a blade or wheel whose rated speed is below the tool's maximum.
Tooth count
Tooth count is the total number of teeth on a circular blade. More teeth can support a finer finish in some material/cut combinations, but the number does not create a universal quality scale.
Fewer or differently shaped teeth may clear chips better in a rip cut. More teeth may suit a crosscut or sheet-good finish. Tooth geometry, hook angle, material, blade diameter, feed, and saw type matter with the count.
TPI on a saw blade
TPI means teeth per inch on many reciprocating, jigsaw, band-saw, and hand-saw blades. It describes tooth density along the blade, not screw threads.
Match blade TPI and tooth design to material thickness and type using the blade manufacturer's instructions. Too few teeth engaged can snag; too many can load or cut inefficiently, depending on the application.
Complete blade-fit checklist
- Exact saw model and manual
- Approved blade type and diameter
- Arbor-hole size and shape
- Kerf and plate-thickness limits
- Maximum blade RPM and saw speed
- Rotation arrow and tooth orientation
- Intended material and cut type
- Guard, flange, riving knife, or splitter requirements
- Blade condition and clean mounting surfaces
Safety boundary
Remove the battery or disconnect power before blade work. Handle teeth carefully while the saw is de-energized. Keep guards and the specified riving knife/splitter installed and aligned. Support the work, stand out of the likely kickback path, and follow the saw-specific manual.
Kickback is not simply normal vibration. On a table saw it can involve sudden workpiece movement from binding, pinching, or misalignment. The prevention details differ across table saws, circular saws, grinders, and chain saws; use the exact manual.
Frequently asked questions
Is the arbor the same as the arbor lock?
No. The arbor is the shaft supporting the blade. The arbor lock is a mechanism used during the approved blade-change procedure.
Is kerf the same as blade thickness?
Not necessarily. Kerf is the cut width; plate thickness is the blade body's thickness.
Does a higher tooth count make a better blade?
No. It must match the material, cut direction, feed, blade geometry, saw, and desired finish.
After checking the interface, browse current tools and verify the exact saw and blade manuals. If the live listing omits arbor, kerf, or rated-speed information, ask product support.