Saw Frame — The U-Shaped Carrier of the Jeweller's Saw
Saw Frame — The U-Shaped Carrier of the Jeweller's Saw
Adjustable hand tool that holds a fine blade under tension for piercing and cutting metal sheet
A saw frame is the adjustable U-shaped hand tool that holds a piercing-saw blade under tension at the jeweller's bench. It consists of a curved metal frame with two clamping points — one at the handle and one at the upper end — that grip the blade between thumb-screws or wing nuts. The depth of the throat, the distance from the blade to the inside of the frame, ranges from about 75 mm in compact frames to 150 mm or more in deep-throat frames intended for large pierced panels. The throat depth determines the maximum reach of the saw into a sheet of metal.
Construction and tensioning
Most saw frames are made from steel or aluminium and either have a fixed length or an adjustable frame that allows broken blades to be reused. A fixed-length frame requires careful blade alignment but is simple and reliable; an adjustable frame, with a sliding bar that can be locked in position, accommodates blade lengths from short broken pieces upward. To install a blade, the lower end is clamped first with the teeth pointing down toward the handle. The frame is then compressed slightly — often by pressing the upper end against the bench edge — and the upper clamp is tightened on the blade. Releasing pressure puts the blade under tension; correct tension produces a clear, high-pitched note when the blade is plucked with a fingernail.
Use at the bench
The saw frame is held vertically with the handle in the dominant hand and the blade passing through a V-notch in the bench peg. The cutting motion is a vertical stroke with very light forward pressure — the blade does the work, and forcing it shortens blade life and tears the work. For internal piercing, a small hole is drilled through the sheet, the frame is opened to free one end of the blade, the blade is threaded through the hole, and the frame is re-tensioned. This is the canonical filigree, fretwork, and pierced-bezel technique.
In the trade
Standard frames from European makers — Knew Concepts, Vallorbe, Bergeon — set the trade benchmark for rigidity and accuracy. The Knew Concepts aluminium frames, popular since the 2000s, are valued for their light weight and high tension stability. Frame choice is largely personal; experienced jewellers often own multiple frames of different throat depths for different work.