A bench machine that clamps the workpiece against a handheld tool that cuts only as deep as its disc radius. How to match each one to the job.

A cut-off saw and an angle grinder both cut metal with an abrasive wheel, and both leave a burr on the cut edge. Beyond that the two tools have little in common. One is a bench machine: the workpiece is clamped in a vice and a large wheel is levered down through it. The other is a handheld tool, carried to wherever the cut has to be made.

Both are standard equipment in fabrication shops and on site, and buyers regularly ask whether one can do the work of the other. For a few cuts either will do. For most, only one of the two is the right tool. This guide covers what each machine is, how the wheels differ, and how to match the tool to the job.

The Short Answer

• A cut-off saw clamps the workpiece and swings a large abrasive wheel through it. It cuts bigger sections in one pass and repeats the same cut at the same angle.
• An angle grinder is held in the hands. It cuts sheet, tube, rebar and bolts in place, and it also grinds and finishes. How deep it cuts depends on the disc radius, not on the motor.
• For repeated cuts on the same stock, choose the cut-off saw. To cut something already fixed in position, choose the grinder. Most workshops keep both, because the two machines do different jobs.

What Each Tool Does

Cut-off saw

A cut-off saw, also sold as an abrasive chop saw, is a bench machine. A base plate carries a vice that clamps the workpiece, and a pivot arm carries the motor and wheel. The operator pulls the arm down through the material. The vice usually rotates, so 90° and 45° cuts are set on an angle scale instead of by eye.

The wheel is large, 355 mm (14 inch) on the machines we build, because wheel diameter sets how deep the tool can cut. Our profile cutting machine runs a 355 mm wheel at 2,450 W and 3,900 r/min on 220–240 V. A section that size cannot be cut in one pass with a handheld tool.

Because the workpiece is clamped and the arm pivots on a fixed axis, every cut comes out square and at the same length. That repeatability, rather than raw power, is the reason a shop keeps one. The trade-off is that the workpiece has to come to the machine, and the machine needs a bench and a mains supply.

Angle grinder

An angle grinder is a handheld motor with the spindle set at right angles to the body. It accepts cutting discs, grinding discs, flap discs, wire brushes, diamond blades and polishing pads, so cutting is one function among several.

Discs run from 100 mm to 230 mm. Our electric angle grinder takes 100, 115 and 125 mm discs at 1,100 W and 11,000 r/min; larger models in the range run 150 and 180 mm discs at lower speed. There is also an 18 V cordless angle grinder with a 100 mm disc, which is the format site work usually asks for when there is no supply nearby.

The limitation is depth. A disc cuts only as deep as its radius, and less in practice, because the guard and backing flange take up part of it. A 125 mm disc gives roughly 30–35 mm, which covers rod, rebar, tube and sheet but not a 100 mm steel section.

Cut-off Saw vs Chop Saw: Naming Differences

In North America, cut-off saw also means a petrol-driven handheld saw with a 300–350 mm blade, used on concrete, asphalt and ductile iron. That is not the bench machine described above, and it competes with a wall saw rather than a chop saw. When a specification says cut-off saw, confirm which machine is meant.

Cut-off Saw vs Angle Grinder: Feature Comparison

Disc Size, Speed and the Safety Limit

Wheels and discs are not interchangeable between the two tools, and this is where they differ most in safety terms.

Every bonded abrasive wheel is rated for a maximum peripheral speed, commonly 80 m/s, so diameter and speed trade off against each other: a large wheel turns slowly, a small disc turns fast. A 355 mm wheel is rated around 3,800–4,000 r/min; a 125 mm disc, above 12,000 r/min.

The rule that matters: the maximum speed marked on the disc must be equal to or higher than the no-load speed printed on the tool. A 125 mm disc rated at 12,200 r/min does not belong on a tool running at 13,300 r/min, and an angle grinder disc must never be fitted to a cut-off saw. Running a wheel above its rated speed is what makes it burst.

Best Uses for Each Tool

Safety: Where the Two Tools Differ

Both tools cut with a bonded abrasive wheel at high speed, so both need eye, face and hearing protection, and neither should be used on wood. Beyond that the risks differ.

• Cut-off saw. The workpiece is clamped and both hands stay on the handles, so the operator stands further from the wheel, and a fixed guard encloses most of it. The risk that remains is a burst wheel, which is why the guard stays on and the wheel must match the spindle speed.
• Angle grinder. One or two hands hold the tool, so the operator is close to the cutting edge, and kickback is a real risk when the disc pinches or meets a hard spot. Keep the guard between disc and operator. Discs above 180 mm are harder to control.
• Both. Never side-grind with a cutting disc or cut with a grinding disc, and store bonded wheels away from moisture and impact. More on the handheld side is in our angle grinder safety guide.

Which Tool Should You Choose?

• The largest section you need to cut. Measure the biggest cross-section in the job. If it will not pass under a 125 mm disc, the cut-off saw is the answer.
• The number of cuts. One or two cuts on site suit the grinder. Fifty identical cuts suit the machine with the vice.
• Whether the workpiece can be moved. If it is fixed, overhead or buried, only the handheld tool can do the job.
• Whether you also need to grind. If you do, you are buying an angle grinder whatever else you buy. Our guide to corded versus cordless angle grinders covers the cordless question.
• The market you are supplying. Voltage and certification decide what can be sold where; see Power Tool Certifications for how CE, GS, ETL and CB apply to powered cutting tools.

For a broader view of cutting tools, see Which Type of Power Saw Do I Need? and Miter Saw vs Circular Saw.

Frequently Asked Questions

Can an angle grinder replace a cut-off saw?

For small sections, yes. Rebar, threaded rod, tube and sheet are routine work for a 125 mm grinder. It cannot replace a cut-off saw on large steel sections, because a disc cuts only as deep as its radius, and it cannot match the repeatability of a clamped vice.

What is a cut-off saw used for?

Cutting metal to length: angle iron, channel, flat bar, conduit, pipe and studding, at 90° or 45°. The vice and pivot arm make it a production tool, so it is used wherever the same cut is repeated.

Is a cut-off saw safer than an angle grinder?

In normal use, yes. The workpiece is clamped, the hands are on the handles and the guard surrounds the wheel, so the operator stands further from the cutting edge. A wheel failure is more serious at 355 mm than at 125 mm, so the disc rating and the guard matter more, not less.

Can a cut-off saw cut wood?

No. Abrasive wheels are not made for wood: the material clogs the wheel, the wheel overheats and kickback becomes likely. Wood is cut with a circular saw or a mitre saw, as covered in our miter saw vs circular saw comparison.

Matching the Tool to the Cut

The two tools are usually listed as alternatives. In practice they do different jobs. A cut-off saw is for cutting the same section the same way, many times, accurately. An angle grinder is for cutting something already in place, and for cleaning up the cut afterwards. Workshops that do both types of work keep one of each, which is why the two sit side by side in most tool catalogues.

Buying cut-off saws or angle grinders for a particular market? Tell us the material, the largest section and the destination. We supply both formats, corded and cordless, with the documentation each market requires — see our cut-off saws and angle grinders, or contact us for a quote.

This article is intended as a general buying reference. Specifications quoted are typical for the class; confirm ratings on the current datasheet before specifying.