Hole Saw Sizes: Chart From 3/4 in to 6 in and Uses

A hole saw is listed by the diameter of the hole it cuts, so a 2 in hole saw makes a 2 in (51 mm) hole. Standard sizes run from 3/4 in (19 mm) to 6 in (152 mm), and the cup material decides what it can cut: bi-metal for wood, plastic and thin metal, carbide grit or diamond for tile, cast iron and masonry. The smaller sizes are listed in the chart below with the job each one is usually bought for.

Hole saw size chart

Size	Metric	Common use
3/4 in	19 mm	Small cable and pipe holes
7/8 in	22 mm	Conduit knockouts for 1/2 in conduit
1 in	25 mm	Door latch edge bore
1-1/8 in	29 mm	Larger cable holes
1-1/2 in	38 mm	Pipe and wire runs through studs
2 in	51 mm	Drain and large pipe holes
2-1/8 in	54 mm	Door lock main bore
3 in	76 mm	Large pipe holes
4 in	102 mm	Vent and duct holes
4-1/4 in	108 mm	Hole for a 4 in duct
6 in	152 mm	Large vents and fan cutouts

Sizes in between exist, and so do metric sizes such as 22, 35 and 51 mm, so check the cup’s printed diameter against the hole you need. For electrical fixtures and ducts, use the cutout size on the fixture’s template, because makers differ.

What are hole saws made of?

Hole saw cups come in four types, and each one cuts a different group of materials.

Type	Cuts	Notes
Bi-metal (HSS teeth)	Wood, plywood, plastic, drywall, thin steel and aluminum	The general-purpose choice; use cutting oil on metal
Carbide-tipped teeth	Hardwood, fiber cement, abrasive board and some metals	Costs more, stays sharp longer in abrasive material
Carbide grit (no teeth)	Tile, cast iron, brick and plaster	Grinds instead of cutting; leaves a rough edge
Diamond	Porcelain, glass, granite and other hard stone	Needs water cooling

For tile and stone, see tile drill bits and drilling porcelain tile. Concrete and brick need a diamond or carbide core bit, as explained in masonry drill bits for concrete and brick.

Arbors and pilot bits

A hole saw cup does not drill by itself. It screws onto an arbor, a shank with a pilot bit in the center, and the arbor locks into the drill chuck. Most sets have two arbor sizes: a small one for cups from about 9/16 to 1-1/4 in and a large one for cups from 1-1/4 to 6 in. The 1/4 in pilot bit keeps the cup centered and keeps it from walking on the surface.

Make sure the arbor fits your chuck. Most arbor shanks are 3/8 in or 1/2 in, and the drill chuck size guide explains how to tell which one your drill takes.

How to cut a clean hole

1. Mark the center of the hole and clamp or hold the workpiece firmly.
2. Fit the hole saw on the arbor and check that the pilot bit sticks out past the teeth.
3. Set the drill to its slow, high-torque speed. Larger holes need lower rpm: use the drill speed calculator or the maker’s chart for the bit and material.
4. Hold the drill with both hands, using the side handle, and start the pilot bit with the cup square to the surface.
5. Let the cup do the work with light, steady pressure. In steel, add cutting oil.
6. In wood, stop when the pilot bit comes through and finish the cut from the other side, so the exit face does not splinter.
7. Back the saw out now and then to clear chips, which keeps the teeth from loading up and overheating.
8. Push the plug out through the slots in the side of the cup with a screwdriver.

Safety

• Hole saws grab. A large cup that jams can twist the drill out of your hands, so use a drill with a side handle and a firm stance, and keep the clutch on if the drill has one.
• Wear eye protection. Chips and hot slugs fly out of metal cuts.
• Diamond saws for tile and stone need water. Use a slow drip or a spray bottle, and keep the cord and the drill body dry.
• Concrete cutting makes silica dust, so wet-cut it or wear a respirator rated for fine dust.

Common mistakes

• Pushing hard. This overheats the teeth and burns the cut; light pressure and a sharp cup cut faster.
• Running the drill too fast on a large cup. The outer edge of a 4 in cup moves much faster than the edge of a small one at the same rpm.
• Using a wood hole saw on steel. Bi-metal teeth survive thin steel with oil, but a wood-cutting cup with a coarse tooth pitch dulls fast on metal.
• Forgetting the plug. A plug stuck in the cup stops the saw from clearing chips; remove it as soon as the hole is through.

When another tool is better

Holes smaller than 3/4 in are a job for a regular drill bit; see the drill bit size chart for the size. For large or odd-shaped holes in sheet material, a jigsaw cutting from a drilled start hole is often easier to control than a big hole saw.

Related guides

• Drill bit sets: which set for wood, metal and masonry
• Do all drill bits fit all drills?