This article covers changing from grass trimmer to brush cutter and from brush cutter to grass trimmer.


There are two types of Qualcast petrol brush-cutters: 1. GDB30B, 2. RG415 - 495409

For the GDB30B, do the following:

Changing from Grass Trimmer to Brush Cutter

  1. Align the slot (C) in the flanged washer (D) with the slot (B) in the gear head (A).
  2. Place the hex wrench (K) through the slots in the flanged washer (D) and gear head (A) to lock them together.
  3. Unscrew the grass trimmer head assembly (F) by hand in clockwise direction.
  4. Remove the cupped washer (E) and flanged washer (D) and then retain it for the blade installation. 
  5. Place the flanged washer (D) over the gear head shaft (G) with the hollow side toward the gear head (A). 
  6. Center the blade (H) on the flanged washer (D), making sure the blade fits flat and the raised hub of the flanged washer goes through the hole in the blade.
  7. Install the cupped washer (E) with the raised centre away from the blade.
  8. Place the blade nut (I) onto the gear head shaft  (G).
  9. Place the hex wrench (K) through the slots in the flanged washer (D) and gear head (A) to lock the heads rotation while tightening the nut. 
  10. Install the blade nut (I) by turning it counterclockwise (left handed threads). 
  11. Tighten the blade nut (I) securely by wrench (J).
  • To change from the brush cutter to the grass trimmer, please follow the instructions in reverse order.

For the RG415, do the following:

  1. Hold the flange with an allen key. 
  2. Unscrew the nut at the bottom clockwise, which will allow you to take off the blade.
  3. Remove another shield-layer.
  4. Still holding onto the flange, fit the strimmer-cutting head onto the shaft.
  5. Rotate anti-clockwise until it screws fully in place.
  6. Remove allen key.
  7. To put the blade back on, remove the strimmer-cutting head and place the shield-washers, the same way you took them off.

Anti-clockwise to tighten the bottom nut^. Make sure to keep the upper flange in place with the allen-key whilst doing this.