T1 or M2: choosing steel for paper guillotine knives
Two high speed steels cover most of the paper cutting market, and the choice between them decides whether your knives wear out slowly or chip early. Here is the honest comparison, and the questions that actually settle it.
What the two grades are
T1 is a tungsten-based high speed steel. It holds hardness at temperature well and resists abrasive wear, which is why it became the default specification for guillotine knives in printing and paper converting.
M2 is a molybdenum-based high speed steel. It gives up a little wear resistance and gains toughness — it bends and absorbs impact where T1 would crack.
| T1 | M2 | |
|---|---|---|
| Base | Tungsten high speed steel | Molybdenum high speed steel |
| Typical hardness | HRC 62–64 | HRC 60–64 |
| Wear resistance | Higher | Good |
| Toughness | Lower | Higher |
| Failure signature | Wears evenly over a long run | Resists nicks and impact better |
| Best fit | High volume, coated and abrasive stock, long uninterrupted runs | Mixed or recycled stock, thick lifts, older machines, shops that hit contamination |
How to actually decide
Choose T1 when the edge wears out before it chips
Steady production, coated art paper, board, long runs between regrinds, and a machine whose clamp and bed are in good order. You are buying edge life, and T1 gives the most of it.
Choose M2 when the edge chips before it wears out
Recycled board with staples, mixed lifts, thick stacks, older guillotines with imperfect parallelism, or a shop where several people load the machine. In that environment a harder edge is a liability: it fails by chipping, and a chipped edge destroys more paper than a slightly softer one that wears evenly.
The rule is simple: look at how your last knives failed. Worn evenly → go harder or stay with T1. Chipped or nicked → toughness, which means M2 or a change of bevel angle.
Three things people get wrong
- Chasing hardness. HRC 65 does not cut better; it chips more. Above the practical range for the stock, every extra point of hardness is bought with toughness.
- Blaming the steel for a setup problem. A knife that chips at one end has a parallelism problem, whatever the grade.
- Ignoring the bevel. Bevel angle changes performance more than the difference between T1 and M2 does. Get the angle right first, then choose the grade.
What we need to quote
Machine model, knife length, height and thickness, hole pattern, the stock you cut most, and how the current knives fail. If you have a drawing, send it — we produce to drawing, not to a catalogue size. Tell us the failure mode and we will recommend the grade and the bevel together.
Frequently asked questions
Is T1 better than M2 for paper guillotine knives?
Neither is better in general. T1 holds an edge longer on abrasive stock; M2 survives impact and contamination better. Decide from how your current knives fail: even wear points to T1, chipping and nicks point to M2 or a stronger bevel.
What hardness should a guillotine knife be?
Most guillotine knives work in the HRC 60–64 range. Higher hardness increases wear resistance but reduces toughness, and paper cutting punishes brittleness with chips. The right number depends on the stock and on how well the machine holds alignment.
Can I use the same knife for thin paper and thick board?
You can, but you will compromise both. The bevel angle that cuts thin stock cleanly is too fragile for board, and the reverse crushes thin sheets. Where both are cut regularly, two knives with different bevels is the cheaper answer over a year.
Do you supply custom lengths and hole patterns?
Yes. Knives are produced to your drawing or to the machine model, including hole pattern, slot positions and bevel angle. Standard sizes are also held for fast shipment.