Shear Blades for Amada, Durma and Yawei Guillotine Shears
Replacement upper and lower blades for Asian-built guillotine shears. On these machines the blade is a rectangular bar with two or four usable edges, and the fit is decided by the blade seat — the length of the bed, the section, the fixing and the rake. Get the section wrong and the blade will bolt up but not cut square.
Section, edges and why four-edge blades are the default
A guillotine shear blade is described by length × width × thickness. Width and thickness come from the blade holder; length from the bed. Most Amada, Durma and Yawei shears run a rectangular section with two long cutting edges on opposite faces, so the blade can be flipped once, or four edges when both the long and the short faces are ground.
| Blade type | Usable edges | When it pays |
|---|---|---|
| 2-edge | 2 (flip once) | Thin beds, light duty, cheapest per blade |
| 4-edge | 4 (flip and rotate) | Production shears — four cutting cycles per blade, less downtime per ton |
| Sectional | 2–4 per section | Beds over 3 m: short sections are cheaper to replace than one 4 m bar and can be shimmed individually |
Upper and lower blades are not the same part. The lower blade is usually the wider one and takes the wear; the upper carries the rake. Ordering a pair as “two of the same” is the second most common error we see after measuring only the length.
Blade clearance is set by material thickness, not by the machine
Clearance between upper and lower blade runs roughly 5–8% of sheet thickness and is adjusted per job. It is the single setting that decides whether you get a clean edge or a burr and a curved cut.
| Sheet thickness | Clearance (typical) | Symptom if too wide |
|---|---|---|
| 0.5–1.0 mm | 0.03–0.05 mm | Burr on the offcut, roll-over on thin sheet |
| 1.0–3.0 mm | 0.06–0.15 mm | Rough fracture face, edge pulled down |
| 3.0–6.0 mm | 0.15–0.30 mm | Twisted strip, blade overload |
| 6.0–12 mm | 0.30–0.60 mm | Heavy burr, audible knock each stroke |
Edge angle by material
| Material | Edge angle | Hardness |
|---|---|---|
| Mild steel, up to 6 mm | 85–88° included | HRC 56–58 |
| Mild steel, 6–12 mm | 88–90° | HRC 56–58 |
| Stainless, 1–4 mm | 86–88° | HRC 58–60 |
| Aluminium, copper | 80–84° | HRC 56–60 |
| High-strength / wear plate | 90° | HRC 60–62 |
Grades we run: 6CrW2Si, 9CrSi, 5CrW2Si for general shearing; Cr12MoV and equivalents for stainless and high-strength plate. Tell us the material mix and the thickest sheet, and we set the angle and hardness to that — not to the cheapest standard.
What to send
| Send this | Detail |
|---|---|
| Machine make and model | Amada, Durma, Yawei, JFY — plus bed length |
| Section | Length × width × thickness in mm |
| Fixing | Counterbore or countersink, hole count and pitch, from a photo with a ruler |
| Upper or lower | They differ; say which, or send both sizes |
| Material mix and max thickness | Sets edge angle and grade |
Frequently asked
Can I fit a 4-edge blade where a 2-edge blade was?
Only if the holder accepts the extra ground faces without changing the blade height. Check the seat depth first — a 4-edge blade is ground on more faces but the section must still fit.
Do you regrind used shear blades?
Used blades can be re-ground and re-edged while the section still has material above the minimum. Send the current thickness and the number of regrinds.
How long is a shear blade supposed to last?
On mild steel at 2 mm, a 4-edge blade commonly runs 20,000–40,000 strokes per edge. Stainless cuts that by half. If yours is far below that, check clearance and hold-down before blaming the blade.
Related: Shearing machine blade overview · Trumpf, LVD & Haco · Guillotine knife vs shear blade
Send your shear model and blade section
Upper and lower blade sizes, fixing photo and material mix is all we need to quote.
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