twibill
A two-edged tool used in gate-type hurdle-making for cutting out mortises, with a flat chisel and a mortise chisel or hook, similar to the much larger French carpenter's tool, the besaiguë (or bisaiguë).
twibill: double-headed mortise cutter for hurdle frames
A twibill is a hand tool with two working heads on a single haft, used primarily in hurdle-making to cut mortises and shape wooden joints. One head is a flat chisel, typically 1 to 1.5 inches wide; the opposite head is a narrower mortise chisel or hook with an inward curve or right-angle bend. The tool weighs 2 to 4 pounds and measures 18 to 24 inches overall, designed to be swung one-handed or struck with a mallet for precise, repeatable cuts in willow or hazel rods.
Hurdle-making, particularly the gate-type frame used for temporary fencing and sheep pens, depends on mortise-and-tenon joinery to lock horizontal rails into vertical stiles. The flat chisel face of the twibill squares the mortise walls, while the hook or angled mortise head chops the bottom of the cavity clean and creates the undercut that locks the tenon in place. By carrying both tools in one implement, the craftsperson avoids constant tool changes during repetitive work.
Relationship to the besaiguë
The twibill is a lighter, more specialized descendant of the French besaiguë (also spelled bisaiguë), a heavier carpenter's tool with a full-width flat axe on one side and a gouge or mortise blade on the other. The besaiguë reached 8 to 12 pounds and was used for major carpentry, including house-frame joinery. English and Welsh hurdle-makers adapted the principle into a smaller, faster tool suited to the thinner stock and the high volume of identical frames required in agricultural work.
The name 'twibill' derives from Old English 'twi-' (two) and 'bill' (blade or cutting edge), making it literally a 'two-blade' tool. The term has remained stable in hurdle-making regions of southern England and Wales, where the trade itself persisted longer than in many other parts of Britain. Regional variation exists: some versions mount the mortise head as a true hook, others as a short beveled blade, depending on local technique and the thickness of the stock being mortised.
A twibill requires regular re-sharpening of both edges, particularly the mortise head, which dulls rapidly from chopping the end grain of hardwood rods. The haft, usually ash or hickory, must be set at a slight angle to allow both heads to strike cleanly; a straight haft will cause one head to miss or glance. Poor balance or a loose head can cause the tool to twist in the hand, making clean cuts impossible and creating risk of the haft splitting under repeated mallet blows.