K773

A direct replacement for the Kongsberg BLD-TZ129 (42435636), Summa 500-9825, and Zünd Z73 (5005572), with no holder modification needed. Fine grain tungsten carbide V-cut blade for V-grooving, bevel cutting, and 0° through cutting on Kongsberg / Esko, Summa, and Zünd flatbed cutting systems.

Designed for cutting PET felt, Zintra®, F-Sorb®, polyester acoustic board, foam board, honeycomb, corrugated board, and other display, packaging, and acoustic materials.

The K873 features an additional cutting edge that reduces the force required for the blade to enter the material. Lower entry force reduces blade deflection, producing a cleaner and more accurate start point at the beginning of the cut path.

Sold individually.

Direct OEM replacement

The K873 is a confirmed drop-in replacement for the Kongsberg BLD-TZ129 (42435636), Summa 500-9825, and Zünd Z73 (5005572). Same form, same fit, same mounting geometry. No holder changes required.

What is V-cutting?

V-cutting uses angled cuts to remove a wedge-shaped section from the material. This creates clean folds, beveled edges, and mitered joints in thick board, acoustic felt, and display materials.

When installed at 0°, the blade can also make straight through cuts, depending on the tool, material, and machine settings. This blade is intended for V-cutting, bevel cutting, and through cutting. It is not a kiss-cut blade.

Fine grain tungsten carbide with an additional cutting edge

The K873 is made from fine grain tungsten carbide for added strength, improved cut quality, and longer blade life. Its tight grain structure helps the blade retain a sharp edge and resist chipping under load. This means fewer blade changes and more consistent cut quality across longer production runs.

The K873 also incorporates an additional cutting edge that reduces the force required as the blade enters the material. Lower entry force helps limit blade deflection during penetration, producing a cleaner and more accurate start point at the beginning of the programmed cut path.

This feature is especially valuable when processing dense PET acoustic felt, Zintra®, foam board, honeycomb, heavy corrugated board, and other materials that can push or deflect a conventional blade during entry.

Common questions

How do I know this fits my machine?

The K873 fits the following machine and tool configurations:

• Zünd G3, S3, and D3 cutters equipped with the VCT1 and blade holder 5206262
• Zünd cutters equipped with the T75 and V-cut insert 3102186
• Kongsberg XL, XN, X, and V cutters equipped with a PowerHead and V-Notch tool holder
• Kongsberg C and XP cutters equipped with an HD or Dual HD unit and V-Notch tool holder
• Summa F Series cutters equipped with a V-Cut Tool installed in the Tangential Module

If your current blade is the BLD-TZ129, 500-9825, or Z73, the K873 is a confirmed drop-in replacement. Not sure which blade or holder is installed? Contact us before ordering and we will confirm compatibility.

What is the advantage of the additional cutting edge?

The additional cutting edge reduces the force required for the blade to penetrate the material. This helps prevent the blade from flexing or deflecting as the cut begins.

Less deflection produces a more accurate start point, cleaner cut-path entry, and more consistent results, particularly in dense PET felt, acoustic panels, foam, and thick structural board.

Why use tungsten carbide instead of HSS?

Fine grain tungsten carbide offers greater strength, edge retention, and wear resistance than a conventional high-speed steel blade. It stays sharp longer, maintains more consistent cut quality, and reduces the frequency of blade changes during production.

These benefits are especially valuable when cutting abrasive PET acoustic felt, Zintra®, F-Sorb®, polyester acoustic board, and other fiber-based materials that can wear an HSS blade quickly.

Combined with the K873’s additional cutting edge, the carbide construction provides longer blade life, lower material-entry force, reduced blade deflection, and a cleaner start point.

Actual blade life depends on the material, cutting depth, speed, tool calibration, and machine condition.

What materials does it cut?

The K873 is recommended for a wide range of acoustic, foam, display, packaging, and corrugated materials, including:

• Acoustic materials: PET felt, Zintra®, F-Sorb®, PET acoustic felt, and polyester acoustic board
• Foam and flexible materials: EVA foam, ethylene-vinyl acetate, neoprene, foam, and cork
• Foam boards: Foamboard, FOME-COR®, and Insite foamboard
• Display and structural boards: Falconboard®, Reboard®, Zanita Board®, sandwich board, and DISPA®
• Corrugated materials: B flute, C flute, E flute, F flute, BC flute, and other corrugated board
• Other sheet materials: Corrugated plastic, matboard, cardstock, and cardboard

If you are cutting something outside this list or need help matching the blade to your material, reach out. We have probably seen the application before.

What cutting depth can it handle?

The blade format supports cutting depths up to approximately 18.2 mm, depending on the machine, tool, holder, cutting angle, and material density. The Zünd VCT1 is designed for materials up to 16 mm thick, while other compatible configurations may allow additional cutting depth.

Always set the blade exposure for the material being processed. Excessive exposure can increase deflection, reduce cut quality, and shorten blade life.

How do I know when to replace it?

Watch the cut quality. If beveled edges become rough, the blade begins dragging through the material, fibers pull instead of separating cleanly, corners start tearing, or pieces no longer release properly, it is time to replace the blade. Edge degradation usually appears in cut quality before the blade fails completely.

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. Blade exposure, cutting angle, speed, depth, material hold-down, and machine condition all affect blade life and finished cut quality.

It is worth asking: When was your machine last serviced? Are your parameters dialed in for this material? Is the V-cut tool calibrated correctly? 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.