K21
A direct replacement for the Zund Z21 (3910314), Esko BLD-SF421 (i-421 / G42458257), Gerber MCT SE21 (895020), Colex T00421, and Summa L25 (500-9811 / 500-9812), with no holder modification needed. Single edge oscillating flat-stock blade for through cutting on Zund, Esko, Gerber / MCT, Colex, and Summa flatbed cutting systems.
Sold individually.
Direct OEM replacement
The K21 is a confirmed drop-in replacement for the Zund Z21 (3910314), Esko BLD-SF421 (i-421 / G42458257), Gerber MCT SE21 (895020), Colex T00421, and Summa L25 (500-9811 / 500-9812). Same form, same fit, same geometry. No holder modification needed.
What is oscillating cutting?
An oscillating blade moves up and down at high speed as it cuts, rather than dragging. This makes it effective on thicker, denser materials where a drag blade would deflect or stall. The K21 is built for through cutting, meaning it cuts completely through all layers of the material, including any backing. The cut piece separates fully from the sheet.
Fine grain tungsten carbide
The K21 is ground from fine grain tungsten carbide, which holds its edge longer than standard carbide under the repeated impact of oscillating motion. On dense materials like corrugated board, honeycomb, and carpet, edge retention matters. A blade that dulls faster means more changeovers, more wasted material, and less consistent cut quality through a run.
Common questions
How do I know this fits my machine?
If your machine uses a Zund Z21 (3910314), Esko BLD-SF421, Gerber MCT SE21 (895020), Colex T00421, or Summa L25 (500-9811 / 500-9812), the K21 is the direct replacement. If you are not sure which blade your machine takes, contact us before ordering. We can confirm the right fit.
What materials does it cut?
The K21 handles corrugated board, foamboard, folding carton, felt, leather, display board, foam rubber, carpet, sandwich board, honeycomb, sandblasting mask, varnish blankets, and 3M VHB. If you are cutting thinner films or vinyl, a drag blade is a better fit for that application. Not sure? Reach out and we can point you to the right geometry.
What do the 63° and 84° angles mean?
The K21 has two angles: a 63° cutting angle and an 84° wedge angle. The 63° cutting angle controls how the blade enters and tracks through the material, while the 84° wedge angle gives the blade body its balance of sharpness and edge durability. Together, they allow clean through-cuts in thick, dense materials with consistent results across a run. These are two properties of one blade, not two blade options.
How do I know when to replace it?
Watch the cut edge. If you see drag, tearing, or the material not releasing cleanly from the cut line, the blade is past its useful life. On thick or abrasive materials, edge wear happens faster. Swap when cut quality drops, not after a set number of cuts.
Getting the most from your cutting table
A fresh blade is a good start. But if you are going through blades faster than expected, or cut quality has become inconsistent, the blade is rarely the whole story. Cut depth, speed, pressure, and machine condition all affect how long a blade lasts and how clean it cuts.
It is worth asking: When was your machine last serviced? Are your parameters dialed in for this material? Is this the right blade geometry for what you are cutting? Could your operators use time with someone who runs these machines every day?
Flatbed Tools offers machine service, preventive maintenance, operator training, and workflow consulting. If something is not cutting right, reach out. We have probably seen it before.