Cumberland vs. Rapid Granulator Blades: Sizing & Compatibility Guide

Cumberland and Rapid are two of the most common granulators in plastic recycling plants worldwide — and two of the most common blade enquiries we receive. Their knives are not interchangeable. This guide explains how they differ, how to identify which you have, and how to order the correct drop-in replacement.

At HK BladeTech we manufacture compatible aftermarket blades for both at our factory in Ma’anshan, China. Below is the practical, plant-floor version of what you need to know.

Cumberland Granulators

Cumberland machines are built around three broad rotor styles, and the rotor style decides the blade:

Open rotor — knives bolt to an open frame; good airflow, common on beside-the-press granulators.
Closed (solid) rotor — heavier, for central granulation of thicker parts.
Segmented rotor — staggered knives for high-throughput recycling.

Common Cumberland sizes we supply replacements for include the 1012, 1216, 1828, X1400, 50B and 56U series, in both rotor (fly) and bed (stationary) configurations. Cumberland rotor knives are typically robust, multi-bolt designs.

Rapid Granulators

Rapid (Rapid Granulator) machines are widely used across Europe and North America and are known for their open- and closed-rotor designs. Replacement knives we commonly supply include the 2036 and CDH / CDM 2442 families, again in rotor and bed versions.

Compared with Cumberland, Rapid blade geometry and bolt patterns are different — even where the overall length looks similar, the mounting holes and bevel will not match a Cumberland knife.

The Key Differences That Matter

Bolt pattern: hole count and spacing differ between the two brands, and even between models within a brand. This is what actually determines fit.
Bevel geometry: cutting angle and hand (left/right) differ; the wrong bevel tears material and raises power draw.
Rotor style: open vs. closed vs. segmented changes the blade body even at the same machine size.
Material spec: both can be supplied in D2 / SKD-11 for standard plastics, or tungsten-carbide inlaid for glass-filled and abrasive feedstock.

How to Identify What You Have

Check the machine nameplate for the make and model, and note whether you are replacing the rotating knives or the fixed bed knives. If the nameplate is gone, send us a photo of the blade with its dimensions and bolt pattern (see our measuring guide) and we will identify it for you.

Not Sure Which Blade Fits Your Machine?

Tell us your granulator make, model, and whether you need rotor or bed knives. We’ll confirm the correct drop-in replacement and send a factory-direct quote in clear English, usually within a few hours.

Request a Quote

Cumberland®, Rapid®, Vecoplan®, Nelmor® and Weima® are trademarks of their respective owners. HK BladeTech manufactures compatible aftermarket replacement blades and is not affiliated with, authorised by, or endorsed by these manufacturers. Brand and model names are shown for reference only, to indicate fitment.