Tools to facilitate proper maintenance

To help you perform the service and maintenance efficiently there's a number of tools available, some mandatory, others just good to have making your job easier:

A: Must have tools

Torque wrench and special bits
Wrong torque of the knife bolts can be devastating – imagine a loose bolt in the cutterhouse

  • Always use a torque wrench to tighten the bolts correctly. Tightening by feel is simply not reliable
  • Torque wrenches need regular calibration to be reliable
  • The special Rapid-designed bits are low profile and fit where standard bits are too long
Feeler gauges

One of the most important tools in your tool box. Check the “health” of your granulators by measuring the physical knife gap and determine when re-sharpening of the knives is necessary.

  • When the gaps are too big between rotating and fixed knives, the plastic is rather "hammered out" than cut. This generates bad regrind, more dust and more noise
  • Checking the knife gaps regularily makes it easy to determine when it's time to re-sharpen knives
  • The table is only a guideline. Your specific application may require a different knife gap to perform optimally.

Manuals and service schemes / log

Download these materials free of charge at for detailed step-by-step procedures for common granulator service tasks.

Well documented service activities (and, of course, the use of Rapid original spare parts) is mandatory to qualify for the Rapid 5-years extended warranty.

B: More handy tools and accessories

Knife setting jig

  • Makes the installation incredibly easy by pre-setting the knives outside the machine.
  • Rapid delivers a set of basic grinding fixtures with the granulator: one for rotating knives, and one for the fixed ones.
  • As an accessory, we can provide a more professional fixture that makes the setting not only easier but also more precise, particularly when it comes to longer knives.

Grinding fixture

  • Re-sharpen knives in the Rapid grinding fixture to get exact knife angles.
  • Rapid knives are designed with a cutting edge and a release angle that makes the cutting more efficient.
  • Sharpening must be done so these relationships are preserved.

Rotor lock

  • Secures the rotor in a locked position when whenever the hopper is opened
  • changing the for simplicity and safety.
  • Removing a knife from the rotor will make the rotor self-rotate if it’s not securely locked, posing a real risk of cutting injury. A temporary way of securing the rotor is to block it by a piece of wood, however, the block can easily come loose and doesn’t offer a firm lock when it comes to tightening the knife bolts, which require a high degree of force.
  • On the 500-Series and 600-Series, this build-in rotor lock is standard. On the 300-Series and 400-Series, the lock can be retrofitted to give an automatic lock whenever the hopper is opened – safe and secure without having to think about it!

Hour counter

  • With an hour counter installed, it’s easy to keep record of how many hours your granulator has been running. You soon learn how long knives remain sharp and can change them in due time before throughput drops and other symptoms of dull knives begin to show.
  • The hour counter is an option that can be retrofitted.

In need of spare parts?

Order your Rapid original parts online for same-day delivery from our stock.