Slate Cutter

Also known as slate guillotine · slate shear · slate trimmer

A lever-action shear, often called a guillotine, that trims roofing slates to size and may also punch nail holes.

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Cite this entry"Slate Cutter." roof.wiki. https://roof.wiki/slate-cutter/ (accessed 2026-11-02).
Action
Lever-operated guillotine shear
Extra function
Nail-hole punch on many models
Traditional alternative
Slater's hammer or zax over a bench iron

A slate cutter is a hand-operated shear used to trim natural or fibre-cement slates to size. Most designs work like a small guillotine: the slate is placed on a fixed bed against a straight edge, and a long lever brings down a blade that snaps or shears the slate along the line. Many cutters also include a punch for making nail holes, so one tool handles both trimming and holing.

head lap Rafter + battens Slates hang in courses from the eave up.Each is nailed (or hooked) to a batten andreaches two courses up, so there are alwaysat least two thicknesses over the roof.
How slates are fixed

Uses

  • Cutting slates at valleys, hips, verges, abutments and around penetrations.
  • Producing half slates and slate-and-a-half widths at verges.
  • Punching nail holes in slates that arrive without them, or when a slate is re-holed for repairs.
  • Trimming fibre-cement and some synthetic slates, depending on the product.

Compared with traditional hand methods

Before mechanical cutters, slaters trimmed slates with a slater's hammer or zax over a bench iron, stake or slater's anvil, striking along the edge to dress it. These hand methods produce the bevelled or chamfered edges characteristic of traditional slating and remain in use, particularly on heritage work. Guillotine cutters are faster and easier to learn, and are common on new roofs and among general roofers. Patents for lever-action slate cutters date back to the 19th century.

Choosing and using

Cutters vary in blade length, which determines the largest slate width that can be cut in one stroke, and in whether they have a built-in punch and measuring guides. A sharp blade and firm support for the slate give cleaner cuts. Cutting from the back of the slate usually produces a better bevel on the visible face, following the same convention as hand dressing. Eye protection is advisable, as small fragments can fly.

Slate rippers remove damaged slates; slater's hammers and zaxes trim and hole by hand; angle grinders with diamond blades are used for some cuts, though they create silica-containing dust that needs control.

Sources

  1. Roofers' slate toolsCupa Pizarras · cupapizarras.com
  2. Slate CuttersTooled-Up · tooled-up.com
  3. US552364A - Slate-cutterGoogle Patents · patents.google.com