Guide · Walk-behind mower blades
Mower blade center-hole shapes
Round, 5, 6 and 7-point star, bow-tie and S-shape center holes, how each is identified, and the maker-stated examples for each shape.
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Short answer
Name the center hole before anything else: round (sized by inner diameter), a 5, 6 or 7-point star, bow-tie, or S-shape. The hole must match your spindle or blade adapter exactly as the blade maker lists it. A matching name is a start, not proof of fit.
Round holes
Round holes are measured by their inner diameter.[1] Oregon lists its 21-inch Gator G3 blade 96-347 with a 5/8-inch center hole[2] and its 21-1/8-inch Gator G3 blade 91-635 with a 3/4-inch center hole.[3] Two blades of almost the same length, two different holes. See round center holes.
Star holes
A star center hole is identified by its number of points, not measured.[1]
- 5-point star. Craftsman's 42-inch blade set CMXGZAM110136 has two blades with a 5-point star center hole.[4] Oregon's Gator G3 blade 95-601 also has a 5-point star.[5] See 5-point star holes.
- 6-point star. Craftsman's CMXGZAM110108 set contains one blade with a 6-point star mounting hole.[6] See 6-point star holes.
- 7-point star. Oregon's 92-105 mulching blade has a 7-point star center hole.[7] See 7-point star holes.
Oregon's Y-shaped hole for 6-point star spindles
Oregon explains that MTD-built blades with a 6-point star are replaced by Oregon blades with a Y-shaped center hole that fits the 6-point star on the spindle.[8] That is Oregon's stated fit for MTD-built mowers only. Oregon's catalog records such holes as "Y, 6 pt. star" with a size, for example 11/16.[9]
Bow-tie and rectangular holes
A bow-tie hole, also called an H-pattern, is identified by name.[1] Oregon explains that MTD-built walk-behind blades with a bow-tie hole are replaced by Oregon blades with a rectangular center hole that fits the bow-tie pattern on the blade adapter.[8] Again, that is Oregon's statement for MTD-built walk-behinds, not a rule for other makers.
Troy-Bilt's blade adapter catalog offers "Bow Tie" and "Round" as filters.[10] The filters do not label each adapter's pattern, so check the part itself. See bow-tie holes and our blade adapter guide.
S-shape holes
Cub Cadet's 42-inch Xtreme mulching blade set 490-110-C202 contains two blades with an S-shape center hole, for Cub Cadet lawn tractors and RZT mowers with 42-inch decks.[11] Craftsman says the S-shaped hole on its CMXGZAM110191 set means the blades cannot be installed upside down.[12] That is a reason to stay with the hole your mower uses. See S-shape holes.
Shapes at a glance
| Shape | How it is identified | Maker-stated examples |
|---|---|---|
| Round | Inner diameter | Oregon 96-347 (5/8 in), 91-635 (3/4 in) |
| 5-point star | By name | Craftsman CMXGZAM110136, Oregon 95-601 |
| 6-point star | By name | Craftsman CMXGZAM110108 |
| Y-shaped (Oregon) | By name and size | Oregon's replacements for MTD-built 6-point star spindles |
| 7-point star | By name | Oregon 92-105 |
| Bow-tie / rectangular | By name | Oregon's replacements for MTD-built bow-tie adapters |
| S-shape | By name | Cub Cadet 490-110-C202, Craftsman CMXGZAM110191 |
A name comes with a record
Oregon's Blades by Length catalog records every hole inside a part-specific record, next to the length, width, thickness and offset.[9] Two 5-point star blades can still differ in length or offset. Use the center-hole identifier to name your hole, then match the whole record.
Approved picks by hole
Picks that fit2 products
5-point star spindles: the Craftsman CMXGZAM110136 set of 2, only if your old part number is on Craftsman's list.
More on choosing
S-shape: the Cub Cadet 490-110-C202 set of 2, for Cub Cadet lawn tractors and RZT mowers with 42 in decks. On Amazon, check that Ships from / Sold by is Amazon.com or the brand.
42-inch set for Craftsman, Husqvarna and Poulan decks by part number
CRAFTSMAN CMXGZAM110136 42 in bagging and side-discharge blade set, set of 2
42-inch S-shape set for Cub Cadet tractors and RZT mowers
Cub Cadet 490‑110‑C202 Xtreme mulching blade set for 42 in decks, set of 2
Picks that fit2 products
More 5-point star sets from Oregon: the D-42-2G, two 21-inch blades for 42-inch decks, or the 96-370, 22-7/8-inch blades the Oregon-store listing sells as a 2-pack for 46-inch decks.
More on choosing
Choose either only if Oregon's replacement list names your old blade number. On Amazon, check that Ships from / Sold by is Amazon.com or Oregon.
Gator mulching blades for 42-inch Husqvarna and Craftsman decks
Oregon D‑42‑2G Gator G3 blade set for 42 in Husqvarna and Craftsman decks, set of 2
Gator mulching blades for 46-inch Husqvarna and Poulan decks
Oregon 96‑370 Gator G3 22‑7/8 in blades for 46 in decks, 2‑pack
Next
Questions
What are the different mower blade center-hole shapes?
Round holes sized by inner diameter, 5, 6 and 7-point stars, bow-tie (H-pattern) holes and S-shape holes. Oregon also uses Y-shaped and rectangular holes for some MTD-built mowers.[1][8]
Can I use a 5-point star blade on a 6-point star spindle?
No. The hole must match the spindle or adapter as the blade maker lists it. Never modify a hole to make a blade fit.
Why does an Oregon replacement have a different hole from my original?
Oregon says its Y-shaped hole fits the 6-point star spindle on MTD-built mowers, and its rectangular hole fits the bow-tie adapter on MTD-built walk-behinds. That is Oregon's stated fit for those mowers only.[8]
Can I drill out a center hole to fit?
No. Never drill, grind, file or enlarge a center hole. Buy a blade the maker lists for your spindle or adapter, or ask a dealer.