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How to Use a Slitting Saw

Guide · Updated October 28, 2026

A slitting saw cuts narrow slots and parts off stock on a mill. The blade is thin and easy to break, so most of the job is a rigid setup, the right direction and a light, steady feed.

Check the slot width

Measure slot width with gage blocks or a pin. Check it with a mic you've verified against gage blocks; the free Gage Block Calculator builds the stack.

Step by step

Mount on an arbor: Use a proper slitting saw arbor with a key or drive pin and clean flanges.
Check direction: Install the saw so the teeth point into the cut when the spindle turns forward.
Hold the part: Clamp the part so the saw has clearance below it and the cut-off piece cannot be grabbed.
Set slow RPM: Large saws run slow; work it out from the saw diameter, not the arbor.
Touch off: Touch the edge or top with paper and set your depth and position from there.
Feed conventional: On manual machines, feed conventional and steady, with lots of coolant or oil.
Clear and inspect: Back out with the spindle running, deburr and check the slot.

Worked example

3 in HSS saw, 0.040 in thick, 30 teeth, in 6061 aluminum: RPM ≈ 300 SFM × 3.82 / 3 ≈ 380. At 0.0005 in per tooth the feed is 380 × 30 × 0.0005 ≈ 5.7 in/min. In mild steel use about 80–100 SFM: around 100–130 RPM and 1.5–2 in/min.

Why saws break

Climb feed pulling the saw into the work, chips packing the gullets, a part that shifts or closes on the blade, and too much depth for the teeth. Use coolant, conventional feed and support both sides of the cut.

Depth and arbor clearance

Maximum depth is the saw radius minus the arbor flange radius. Use the smallest saw that gives the depth you need, because a smaller saw is stiffer.

Tips

Indicate the vise first: indicating a vise.
Use a edge finder to locate the slot.
Check slot width with a pin or blocks; see plug gage basics.
Speeds: milling speeds and feeds.

FAQ

Which way does a slitting saw go on?

Teeth facing into the cut for the spindle direction; check before you start the spindle.

Should I climb or conventional cut with a slitting saw?

Conventional on manual machines; climb only on rigid machines without backlash.

What RPM for a slitting saw?

Base it on the saw diameter; a 3 in saw in aluminum runs about 380 RPM.

How deep can a slitting saw cut?

Saw radius minus the arbor flange radius, less a little clearance.

Why does my slitting saw wander?

Thin saws flex; reduce feed, use a smaller saw and support the work.

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