VIABRICO Brush Cutter Blade Adapter kit, Trimmer Attachments for Stihl String Trimmers Brush Cutter

What It Is

The VIABRICO Brush Cutter Blade Adapter Kit lets you attach standard brush cutter blades (with a 25.4mm or 1-inch center hole) to Stihl string trimmers that use a 10-tooth splined drive shaft. It’s designed for converting a trimmer head into a brush-cutting setup for heavy weeds, saplings, and thick undergrowth.

Fitment & Compatibility

• Fits Stihl models with a 10-tooth splined output shaft (common on FS 40, FS 45, FS 55, FS 56, FS 70, FS 80, FS 90, FS 100, FS 130, FS 200, FS 250, FS 350, FS 400, FS 450, and KM 90, KM 100, KM 110, KM 130 Kombi units).
• Does NOT fit Stihl models with a 8-tooth spline or round shaft (older FS 38, FS 44, or many homeowner-grade units).
• Blade compatibility: Works with blades that have a 25.4mm (1-inch) center hole and a 4-bolt mounting pattern (common on most universal brush cutter blades).
• What to check before buying:
  1. Count the splines on your trimmer’s output shaft (must be 10).
  2. Measure the shaft diameter – should be ~20mm.
  3. Confirm your trimmer has a metal gearbox (plastic gearboxes may not handle brush cutter loads).
  4. Verify the blade you plan to use has a 25.4mm center hole and 4 bolt holes (typically 8mm diameter, 40mm apart).

Key Things to Know

• Quality: The adapter is made of hardened steel, but the included bolts and washers are basic zinc-plated steel – replace with stainless hardware if you’re in a wet or salty environment.
• Installation difficulty: Easy (5-10 minutes) – remove the trimmer head, slide the adapter onto the shaft, align splines, and bolt the blade on. You’ll need a 10mm socket and a hex key (not included).
• Common gotcha: The adapter’s retaining nut is left-hand threaded on most Stihl models – tighten counterclockwise, loosen clockwise. Forcing it the wrong way can strip the shaft.
• Noise/vibration: Some users report minor vibration with cheap blades – balance the blade before use for smoother operation.

Should You Buy It

If you own a compatible Stihl trimmer with a 10-tooth spline and need a budget-friendly way to switch between a string head and brush blade, this kit works. It’s not as durable as Stihl’s OEM adapter (which costs 3x more), but for occasional brush cutting or light-duty clearing, it’s a solid value. Avoid it if you’re running a commercial operation or need a quick-release system.