Metal hole saw is a widely used drilling tool in metalworking. It is really reliable solution for the sheet metal drilling process. Regular drill bits are good for narrow holes. But for the wider hole, that is not a good solution because wider drill bits are expensive. So the best solution is a metal hole saw.
Metal hole saws are mainly used in 3mm – 10mm sheet metals. Metal hole saws are made with HSS and carbide tips. It has a pilot drill bit to drive the saw inside the metal, and a circular saw is used to cut and remove the metal parts while it is rotating.
When using a metal hole saw, it requires high torque. When it rotates, it tent to interact with a larger surface. Hence it gets hot easily and needs to use coolant continuously.
What Is a Metal Hole Saw?
Metal hole saw is a cutting tool rather than a drill bit. It has a circular saw path. When it rotates, it can cut the path due to the cutting edges (saw teeth). A hole saw has a wider diameter than a drill bit. Hence it can use to drill wider holes that drill bits can’t drill.
Always metal holes are suitable for through holes. When you use a metal hole saw, you should have a pilot hole in order to drive the hole saw into the material.
The saw comprises a circular blade with teeth on its outer edge that is often made of carbide and fits tightly into a hole in a holder or arbor that matches.
An electric drill with the arbor fixed allows the operator to feed material against the spinning blade. Applying lubricants and operating at low speeds increases the lifespan of a hole saw drill bit.
Metal Hole Saw Usage
Applications of the hole saw;
- Metal hole saws are suitable for drilling through holes.
- Drilling holes to accommodate cable and electrical runs.
- Create cutouts in the ceilings for the placement of downlights, fittings, or lighting fixtures.
- Installing taps and other hardware on worktops, bathtubs, and sinks.
- Installing rails, locks, and other hardware for doors and cabinets.
- Installation of drainage pipes or duct runs through walls and kitchen cabinets.
- General joinery, woodworking, and DIY tasks
What Is the Cutting Depth of Hole Saw Drill Bits?
It is the entire volume of metal eliminated by the cutting tool during each pass. It is written in millimeters. Depending on the kind of tool and work material, it may change.
- It is mathematically equal to half of the diameter difference.
- Cutting depth (t) = D-d/2 mm
- Usually, have a maximum depth of cut of about 30mm.
- Although, some of the Bi-metal Hole saw’s cutting depth is 38mm.
- The 3-inch diameter hole saw has a 1.1 inch (27.94mm) cutting depth.
What Materials Can Be Drilled Using Metal Hole Saw Drill Bit?
Metal hole saws can be used for various materials, additionally for metals.
Suitable for:
- Metal,
- Mild Steel,
- Alloy Steel,
- Stainless Steel,
- Cast Iron,
- Brass,
- Bronze,
- Wood: To prevent splinters, finish the hole from the opposite side.
- Aluminum:
- Plastic: Thin plastics can be cut with a hole saw, but if you use a drill in reverse and slow, the plastic won’t melt.
- Iron,
- Copper,
- Stone,
- FRP
* No matter what type of material the holes will be cut in, if it is done quickly, lubricant should be used.
What Are the Sizes of Metal Hole Saws?
Normally, metal hole saw sizes start from the 16mm, and it can spread over 150mm. When its diameter is wide, its friction force has increased and needs more power to drive the hole saw. So it is not highly recommended to use a wider hole saw every time.
| Diameter /(mm) | Steel | Cast Iron | Non-Ferrous | Plastic |
| 16 | 550 | 365 | 730 | 880 |
| 19 | 460 | 300 | 600 | 740 |
| 22 | 390 | 260 | 520 | 640 |
| 25 | 350 | 235 | 470 | 560 |
| 29 | 300 | 200 | 400 | 480 |
| 32 | 275 | 180 | 360 | 440 |
| 35 | 250 | 165 | 330 | 400 |
| 38 | 230 | 150 | 300 | 370 |
| 41 | 210 | 140 | 280 | 340 |
| 44 | 195 | 130 | 260 | 320 |
| 48 | 180 | 120 | 240 | 290 |
| 51 | 170 | 115 | 230 | 270 |
| 54 | 160 | 105 | 210 | 260 |
| 57 | 150 | 100 | 200 | 250 |
| 60 | 140 | 95 | 190 | 230 |
| 64 | 135 | 90 | 180 | 220 |
| 67 | 130 | 85 | 170 | 210 |
| 70 | 125 | 80 | 160 | 200 |
| 73 | 120 | 80 | 150 | 180 |
| 76 | 115 | 75 | 140 | 170 |
| 83 | 105 | 70 | 140 | 170 |
| 89 | 95 | 65 | 130 | 160 |
| 95 | 90 | 60 | 120 | 150 |
| 102 | 85 | 55 | 110 | 140 |
| 114 | 75 | 50 | 100 | 120 |
| 127 | 65 | 45 | 80 | 110 |
| 140 | 60 | 40 | 75 | 100 |
| 152 | 55 | 35 | 70 | 90 |
According above data, the RPM must be low when using a large hole saw.
