With 4 types and 13 models there is a Hammerhead Performance Trimmer Head that will fit 90% of all trimmers.

The exclusion being trimmers with fixed extended spindles or model exclusive original parts. This trimmer head is a likely fit for any curved shaft trimmer with a receiving bolt that is 1″ or shorter. Longer receiving bolts (2″ – 3″ in length) are “extended” receiving bolts and require a trimmer head of a completely different design.

FIND OUT IF WE HAVE A MODEL THAT WILL FIT YOUR TRIMMER BY USING OUR PART LOOKUP system.
HAMMERHEAD TYPE 4 – THRESHER 425 for curved shaft trimmers
Extended Wear Nylon – a premium polymer composite construction providing the best wear characteristics in the industry. Large, 1″ x 1″ x 1″, billet aluminum arbor for greater stability.

Capacity: 15′ x .080 dia. 13′ x .095 dia. 10′ x .11 dia.
Outer diameter: 4.25″
Height: 2.5″

What makes Hammerhead Performance Trimmer Heads so tough?

  • All nylon parts are not created equal ⋅ Because most manufacturers settle for good enough — stock trimmer heads don’t contain the best and costliest materials. In general, OEM trimmer heads contain a nylon reinforced with glass fillers. In contrast, Hammerhead Performance Trimmer Heads use a high-grade, nylon. One strengthened with an elastic additive designed to distribute impact force. As a result, Hammerhead performance trimmer heads can withstand higher levels of impact stress, longer terms of abrasive wear 500 times beyond ISO shock test standards.
  • A better fit—right out of the box ⋅ Hammerhead performance trimmer heads set a higher standard. When we make trimmer heads, each part measures within tenths of millimeters from each other — meaning a glove-like fit and no fiddling with stubborn parts.  No struggle to put together a trimmer head. With Hammerhead all parts slide together smoothly ever single time.
  • A wobble free arbor ⋅ Hammerhead performance trimmer heads bolt to a billet aluminum center arbor. A better way to attach a trimmer head. While all other trimmer heads provide a universal “bag of bolts” and ask you to pick out one that fits okay. Hammerhead has a large center arbor that is friction fitted and balance checked at the factory for an accurate and smooth spin. One specifically sized to your trimmer’s receiving bolt.
  • Superior debris protection ⋅ Trimmer heads fail when dirt and grit get inside. Debris that will quickly wear the moving parts that advance the line. Hammerhead’s large, overlapping interior walls interlock and block foreign matter from entering critical mechanisms.