Precision Carbide Slotting Knives for Rigid & Gift Box Grooving
Packaging & Board Knives
Carbide slotting knives for greyboard V-grooving on rigid and gift box lines. Supplied as left- and right-hand pairs in five stock sizes from 50 × 12 mm to 60 × 15 mm, 2.0 / 2.2 mm thick, in GS05U wear-optimised and GS20U tough carbide grades. Clean grooves without tearing or fraying the board face, adjustable to board thickness.
- ■Material: High-grade tungsten carbide
- ■Application: Greyboard V-grooving on rigid and gift box lines
■ ISO 9001:2015 Certified
■ In-House Heat Treatment
■ Strict Dimensional Tolerances
■ Global Door-to-Door Delivery
[ Engineering Reference ]
Decisive Specifications
| Material | High-grade tungsten carbide |
|---|---|
| Grades | GS05U (wear) / GS20U (toughness) |
| Length | 50 / 60 mm |
| Width | 12 / 15 / 16 mm |
| Thickness | 2.0 / 2.2 mm |
| Supply | Matched left- and right-hand pairs |
| Application | Greyboard V-grooving on rigid and gift box lines |
■ All values verified via CMM inspection · ISO 9001:2015
[ RFQ Prompt ]
Need a Specific Size or OEM Replacement?
Don't see your exact specs? Send us a blueprint, a worn sample, or just your machine model. Our team will review the details and provide a tailored quotation.
[ Material Selection ]
Which Steel Grade Should You Order?
The grade decision on slotting knives is wear against toughness, and the board tells you which one you need. Clean virgin greyboard wears an edge; recycled board with inclusions chips it.
| Grade | Hardness | Best For | Trade-off |
|---|---|---|---|
| GS05U | Higher hardness, wear-optimised | Standard virgin greyboard on long production runs — the default grade | Less forgiving of inclusions; chips rather than wears if the board is contaminated |
| GS20U | Higher toughness | Thick board and recycled board carrying grit or other inclusions | Shorter edge life on clean board than GS05U |
If your board mix includes recycled stock at all, GS20U usually wins on total cost even though it loses on edge life — a chipped knife is scrapped, a worn one is reground.
[ Standard Reference ]
Common Standard Dimensions
| Item | L × W (mm) | Thickness T (mm) |
|---|---|---|
| 1 | 50 × 12 | 2 / 2.2 |
| 2 | 50 × 15 | 2 / 2.2 |
| 3 | 50 × 16 | 2 / 2.2 |
| 4 | 60 × 12 | 2 / 2.2 |
| 5 | 60 × 15 | 2 / 2.2 |
[ Technical Audit ]
Engineering Advantages
Left and Right Supplied as a Pair
The two knives form the groove walls together, so they are ground, matched and shipped as a pair. Running a new knife against a worn one produces an asymmetric groove that folds off-square — a defect that shows through the wrap on exactly the products that can least afford it.
Grooves That Do Not Tear the Face
Edge geometry is ground to sever greyboard fibre rather than push it, so the groove walls stay clean and the face liner does not fray. On rigid and gift box work the groove is the difference between a fold that looks machined and one that looks damaged.
Adjustable to Board Caliper
Knife gap is set to the board being run, so a single pair covers a range of calipers instead of being locked to one thickness. A line moving between 1.5 mm and 3 mm greyboard adjusts rather than re-tools, provided the groove width stays in range.
[ System Inventory ]
Related Blade Categories
View All →
[ Knowledge Base ]
Product FAQs & Buying Guidance
Technical FAQs
01Can I replace just one knife of a pair when only one is worn?
+−
Can I replace just one knife of a pair when only one is worn?
You can, but it is usually a false economy. The two knives form the groove walls together, so a new knife working against a worn one cuts an asymmetric groove and the board folds off-square. On rigid and gift box work that shows through the wrap. If one knife of a pair has failed early, it is worth finding out why — an early single-knife failure normally means an inclusion strike or a setting problem, and both will happen again to the replacement.
02GS05U or GS20U — how do I choose?
+−
GS05U or GS20U — how do I choose?
By what is in the board, not by how long the run is. GS05U is harder and wears more slowly, which makes it the right grade for clean virgin greyboard. GS20U is tougher and survives inclusions, which makes it the right grade for thick board and recycled stock. The failure modes are different and that is the whole decision: a worn knife is reground and returned to service, a chipped one is scrapped. If your board mix includes recycled material at all, GS20U usually costs less over a year.
03My grooves are fraying at the face. Is that the knife or the setting?
+−
My grooves are fraying at the face. Is that the knife or the setting?
Check the edge first. A fraying groove face is the signature of an edge that has stopped severing fibre and started pushing it — the same failure that shows as a furry cut on any board application. If the edges are still keen, look at the knife gap relative to board caliper: too wide and the board is torn open rather than cut, too tight and the face is crushed. Setting problems tend to appear immediately after a changeover, edge problems appear gradually.
04Can you make lengths outside 50 and 60 mm?
+−
Can you make lengths outside 50 and 60 mm?
Yes. The stock sizes are the ones ordered most often, not a limit — lengths, widths and edge geometry are made to drawing. If you do not have a drawing, send a worn knife or photographs with a caliper in frame and we will produce a dimensioned drawing for your approval before manufacture.
Why Choose Sureay
01Are these quoted per knife or per pair?
+−
Are these quoted per knife or per pair?
Per pair, because that is how they cut and how they should be changed. Tell us how many grooving stations the line runs and how many pairs you consume in a typical month, and we will quote a schedule rather than a one-off quantity — most rigid box lines are better served by a standing order than by ordering when the last pair fails.
02Which slotting machines do you supply for?
+−
Which slotting machines do you supply for?
Knives are made to the machine, so any greyboard V-grooving or rigid box slotting line is in scope once we have the knife geometry. Send the machine make and model together with the dimensions of the knives you run now — or a worn sample — and we will match them. We would rather work from your actual tooling than from a compatibility claim.
03What is the lead time?
+−
What is the lead time?
Stock sizes typically ship within a few working days of order confirmation. Made-to-drawing geometries run 15–25 working days from drawing approval. Repeat orders against an approved drawing quote same-day, since the geometry stays on file.
Reach Our Team
Get in Touch with Our Engineers
Contact Our Team
Discuss your requirements directly with our engineers.
Request a Quote
Our engineering team responds within 2 hours.