Hole Saw Size Chart: Locksets, Pipe Runs, Downlights — and the Right RPM

A hole saw is the cheapest way to put a large, round, accurate hole in almost anything — and the tool most often bought one size wrong. The cup cuts exactly its stated diameter; there is no easing a 51 mm hole out to 54 with the same saw. So the buying question is never "roughly two inches" — it is the number on this chart.

Job-to-size chart

Pipe holes: measure the OD, add clearance

Pipes are named by nominal bore, not outside diameter, which is how a "1-inch pipe" refuses to pass through a 1-inch hole. Measure the actual OD, add 3–6 mm clearance, and round up to the nearest saw in the kit:

Which saw body: bi-metal, TCT or diamond

From our range

Industrial M42 Bi-Metal Hole Saw with Arbor (8% Cobalt) – Fully Customizable Sizes

M42 bi-metal with 8% cobalt — the spec to stock when the same saw meets wood on Monday and stainless sheet on Tuesday.

From our range

Industrial YG10X TCT Hole Saw for Stainless Steel (3-Ply Blade) – OEM Sizes

YG10X TCT three-ply body for stainless — carbide teeth where bi-metal glazes and stalls.

RPM: large diameter means low speed

A hole saw is a big-diameter cutter, so the rim moves fast even when the chuck turns slowly — the same maths as the drill speed chart. Run lockset-size saws at drill-press speeds, not driver speeds:

Depth of cut: the cup is only 40 mm deep

• A standard cup cuts about 38–40 mm of material before the slug hits the backplate. For a thicker beam, drill until the pilot exits, then finish from the far side — the pilot hole is the register that lines the two cuts up.
• Stacked sheets must be clamped hard together, or the teeth snag the gap between layers and tear the saw sideways.
• Arbors are size-split: cups up to 32 mm mount on a ½"-20 thread, 35 mm and above on ⅝"-18 with drive pins — the reason one arbor never fits the whole kit.

Technique in sixty seconds

• Keep the pilot bit sharp and proud — it steers the whole cut; a wandering pilot ovals the hole.
• In wood, drill until the pilot just breaks through, then finish from the far side — the two cuts meet with no splintered exit.
• In sheet steel, a strip of wax or cutting paste on the teeth doubles the number of holes per sharpening.
• Use the slots in the cup to lever the slug out with a screwdriver — never run the saw to spin the slug free.
• On stainless, everything in the stainless drilling guide applies: low speed, real pressure, never rub.

For the counter and the container

Hole saws sell two ways: the 54 mm + 25 mm pair to anyone fitting locks, and kit boxes to electricians and plumbers who want the range in one case. Arbors are the quiet repeat business — the saws outlive their arbors, and quick-change arbors and kits restock all year. For tile and stone work, pair the display with diamond hole saws so the fitter leaves with both substrates covered.