Sawing and Piercing Metal
Saw piercing is one of the foundational skills you’ll need to master as a jeweler. It's the process that transforms a plain sheet of metal into detailed, intricate designs, opening up endless creative possibilities. While many are familiar with sawing wood, sawing metal can seem trickier at first. That’s why this guide covers essential tools and techniques to help you improve your metal sawing skills. With patience and practice, you'll soon be sawing with precision every time.
Sawing
Saw Frames: A jeweler’s saw frame looks similar to a small fretsaw and is made of flexible steel that holds the blade in place with tension. The blade is secured using wing-nut clamps at either end of the frame. Saw frames come in various sizes, ranging from 3 to 6 inches, based on the depth from the blade to the back of the frame. A 3-inch frame is generally good for small projects, but the size you choose ultimately depends on your personal preference.
You also need to decide between an adjustable or fixed saw frame. Adjustable frames allow you to use broken blades by altering the size, while fixed frames only accommodate standard-sized blades.
Newer frames have advanced designs with features like quick-release blade clamps and cam-lever tensioning mechanisms. These frames are made from lightweight aluminum and won't flex like traditional frames. Some even allow you to rotate the blade 45 degrees to get into hard-to-reach areas.
Saw Blades: Jeweler’s saw blades are sold in bundles of 12 or by the gross (144) and come in a range of grades from coarse to very fine. The grade is based on the number of teeth per centimeter, with coarser blades having fewer teeth and finer blades having more. The thicker the metal, the coarser the blade you’ll need. The table below offers a guide to selecting the right blade based on the thickness of your metal:
| Saw Blade Specification | Blade Thickness (mm) | Blade Width (mm) | Blade Length (mm) | Teeth per cm | Corresponding Drill Size (mm) | Suitable Metal Gauge (mm) |
|---|---|---|---|---|---|---|
| Grade 4 | 0.38 | 0.8 | 130 | 15 | 0.8 | 1.0 – 1.3 |
| Grade 3 | 0.36 | 0.74 | 130 | 16 | 0.8 | 0.9 – 1.2 |
| Grade 2 | 0.34 | 0.7 | 130 | 17.5 | 0.7 | 0.9 – 1.1 |
| Grade 1 | 0.3 | 0.63 | 130 | 19 | 0.7 | 0.8 – 1.0 |
| Grade 0 | 0.28 | 0.58 | 130 | 20.5 | 0.6 | 0.6 – 0.95 |
| Grade 2/0 | 0.26 | 0.52 | 130 | 22 | 0.55 | 0.6 – 0.8 |
| Grade 3/0 | 0.24 | 0.48 | 130 | 23.5 | 0.5 | 0.6 – 0.7 |
| Grade 4/0 | 0.22 | 0.44 | 130 | 26.5 | 0.5 | 0.5 – 0.6 |
| Grade 5/0 | 0.2 | 0.4 | 130 | 28 | 0.4 | 0.4 – 0.55 |
| Grade 6/0 | 0.18 | 0.35 | 130 | 32 | 0.4 | 0.35 – 0.5 |
| Grade 8/0 | 0.17 | 0.3 | 130 | 30 | 0.3 | Up to 0.4 |
You don’t need every grade of saw blade; a small selection of coarse, medium, and fine blades will cover most of your needs. The medium grades (1/0 or 2/0) are the most commonly used, so make sure to have plenty of those on hand.
Installing a Blade in the Saw Frame:
- Sit at your bench and secure the saw frame between your chest and the edge of the bench or your bench peg.
- Position the blade with the teeth facing towards you, then clamp one end into the saw frame using the wing-nut. Don’t over-tighten with pliers, as this can damage the screws.
- Push the handle gently with your chest to flex the frame, then secure the second wing-nut to hold the blade in place.
- Test the tension by plucking the blade. You should hear a sharp "ping" sound. If not, loosen the blade and try again.
Marking Out and Measuring: Before sawing, mark and measure your metal clearly. You can scribe lines using a scriber or dividers, or transfer a design from tracing paper using graphite and Plasticine. Once transferred, go over the lines with a scriber for a permanent mark.
Starting to Saw:
- Hold your metal securely on the bench peg, and grip the saw in your opposite hand.
- Keep the saw vertical, with the blade facing forward, and start by gently drawing the blade downward along the marked line.
- Use long, steady strokes for straight cuts and shorter, controlled strokes for curves. Remember that the blade cuts on the downstroke, and relax your grip to avoid breaking the blade.
Piercing
Why Pierce? Piercing is essential for sawing in areas that are otherwise inaccessible, such as the center of a design. By drilling a small hole, you can thread the saw blade through and cut from the inside out.
Tools for Piercing:
- Scriber: Marks designs on the metal and helps position drill holes.
- Center Punch: Creates a small indentation in the metal to guide the drill bit.
- Bow Drill/Archimedean Drill: Manual drills that offer precise control for beginners.
- Pendant Drill/Rotary Hand Drill: Mechanized tools for more efficient drilling, often controlled by a foot pedal.
- Bench Mounted Pillar Drill: The most stable and precise tool for drilling.
Piercing an Access Hole:
- Scribe your design onto the metal and mark the drilling spot with a center punch.
- Use the appropriate drill size for your saw blade and drill the hole carefully.
- Thread the saw blade through the hole, clamp it in place, and begin sawing out your design.
Troubleshooting
- Breaking Blades: Check your blade tension and ensure you're using the correct blade for the thickness of your metal.
- Blade Sticking: Apply a lubricant, like beeswax, to ease the sawing motion.
- Arm Fatigue: Make sure you’re seated properly and letting the blade do the work.
Mastering sawing and piercing techniques takes time, but with practice, you’ll be able to create intricate designs with ease.
0 commenti