Lawn Mower Blades Common Blade Measurements Length
Center Hole Dimensions / Diameter
Outer Hole Dimensions / Diameter
Center to Center
L-Cut: Counterclockwise rotating blade; cutting-edge is on opposite side of blade.
All Oregon® Blades are 30/30 .030" 30˚ Air Lift Side View Thickness Offset End View
Blade Arbor Hole Types
5 or 7 Point Star Center holes may be 5 or 7 point star shaped.
The two sizes of the 6 point star. If your blade spindle has a bolt and lock washer that holds the blade to the machine you would use the 11/16" star or “Y” blade
Square or Rectangular The MTD built blades on many walk behind lawn mowers have a “bow-tie” hole. In this case the Oregon replacement blade will have a rectangular center hole which will fit on the bow-tie pattern on the blade adapter.
Bow-tie 5-point Star Rectangular 7-point Star Bow-tie / Rectangular
If your blade is secured with a large flange nut then you would use the 5/8" star or “Y” blade
6-point Star 5-point Star Bow-tie “Y” center holeRectangular 7-point Star 6-point star Bow-tie / Rectangular “Y” center hole
MTD Blades The MTD built blades (Bolens, Cub Cadet, Troy-Bilt, White, Yard Machine and Yardman) may have a 6 point star. Oregon replacement blades will have a “Y” shaped center hole which will fit exactly on the 6 point star on the blade spindle.
Bow-tie 6-point Star Rectangular “Y” center hole Bow-tie / Rectangular 6-point star “Y” center hole
“Y” center hole
6-point star “Y” center hole Lawn Mower Blades 329 LG