The saw traditionally used by jewellers, known as a piercing saw, looks very much like a fretsaw or hacksaw. That is, a fine-toothed blade is held under tension in a metal frame. Frames are available in a variety of sizes from 2” up to approximately 8”. If you should need a deeper throated saw, it is possible to substitute a fretsaw frame, which will extend the range to almost 18”.

Although these saws can be used for cutting other materials, such as wood or plastic, they are really designed for cutting fine detail into soft metal, such as silver. The blade is held under tension by between clamps at each end of the frame.

As an aside, if you wondered why a jewellers’ saw is known as a piercing saw, the name is derived from the practice of drilling, or piercing, a hole when piercing internal spaces, as in filigree work.

Fitting a Saw Blade

  1. Press the handle your upper abdomen sternum (chest bone) so that the frame faces away from you.
  2. Loosen the clamp furthest from you and insert the top end of the blade, ensuring that the teeth face outwards and point towards you
  3. Tighten the top clamp
  4. Loosen the clamp nearest to you and slip the bottom end of the blade between the plates.
  5. As you tighten the clamp, put pressure on the frame by leaning forward against the handle.
  6. If you pluck the blade (imagine plucking a guitar string) you should here a pleasant pinging sound. If the sound you hear is dull, you need to put the blade under more pressure. The aim is to get it held really tightly within the frame.

Using the Piercing Saw

  1. Piercing saws are designed to be used vertically. If you try to cut with the blade held in a horizontal position all you will achieve is lots of broken blades.
  2. The blade should be kept well lubricated so, before piercing, run it through beeswax or Cut Lube. At a pinch you could also use household soap or candle wax, although these tend to clog the blades.
  3. Put on your safety glasses!
  4. Support the metal on your bench peg
  5. To start the first cut, hold the saw at about five degrees from vertical; in other words, tilt it as little as possible. Then pull the blade gently in a downward motion until you feel the saw ‘bite’ into the metal.
  6. Continue sawing with the saw blade held as vertically as possible and moving in a precise up-and-down motion. The more relaxed you are, the easier this will be, so loosen up!

Choosing your Saw Blade

Blades for piercing saws come in a range from 8/0 (pronounced 8-aught), which is the finest, through 0, and then up to 8, which is the coarsest. Finer blades have more teeth per inch (tpi) than the coarser blades, with blades graded as 0 having 54 tpi. The general rule of thumb is:

  • 8/0 for very fine piercing
  • 3/0 for gold and platinum
  • 0 to 2/0 for silver

There is a chart (courtesy of George Harper East) giving more detailed information on saw-blade sizes in the resources section of the Guild site.

 

 

Article by Di Sandland

Image courtesy of Dave Cushman