As a DIY nut, I consider only several brands to be 'a must' to have around. One of them is Dremel due to the consistent quality tools they come up with.
Sure, usually when people think Dremel, it's all about their rotary gadgets. However, their saws absolutely rock too.
When I first wrote this, I went in-depth with the Dremel Saw Max and its significant improvement, the Ultra Saw. I didn't see why you wouldn't get the Ultra Saw back then, and that question has since been settled: Dremel no longer sells the Saw Max.
This page was updated in October 2026. Dremel has retired the Saw Max (SM20), and the Ultra Saw is what it sells in its place. Dremel describes the Ultra Saw as a multi-saw that can do everything the Saw Max can do, and more. The Ultra Saw kit I originally linked (US40-01) has been replaced by the US40-04 kit, and Dremel now also makes a cordless Ultra Saw, the US20V. Every spec, cut, material and safety point below is worded the way Dremel states it.
The two Ultra Saw kits Dremel sells now:
- Corded: Dremel Ultra Saw US40-04
- Cordless: Dremel Ultra Saw US20V-01
Dremel Saw Max vs Ultra Saw at a glance
| Saw | Status | Power (per Dremel) | Rated speed (per Dremel) | Max. wheel diameter (per Dremel) | Max. cutting depth (per Dremel) | |
|---|---|---|---|---|---|---|
| Saw Max SM20 (corded) | Retired (Dremel's published figures from before it was retired) | 6 A | 17,000 RPM | 77 mm (about 3", per Dremel's international manual) | 3/4" (21.5 mm) | n/a |
| Ultra Saw US40 (corded, 120V) | Current (US40-04 kit) | 7.5 A | 13,000 RPM | 4" (102 mm) | 3/4" (21.5 mm) | Check price on Amazon |
| Ultra Saw US20V (cordless, 20V Max) | Current (US20V-01 kit) | 20V battery | 15,000 RPM | 4" (102 mm) | 3/4" (21.5 mm) | Check price on Amazon |
Both Ultra Saws use an 11 mm (.433") wheel arbor, according to Dremel's manuals.
What the Ultra Saw added over the Saw Max
Here's the summarized list of reasons I gave for picking the Ultra Saw, now checked against what Dremel states:
- More power: Dremel rates the Ultra Saw US40 at 7.5 amps; its published figure for the Saw Max, before it was retired, was 6 amps.
- Bigger wheels: the US40 takes wheels up to 4", where the Saw Max took wheels up to 77 mm (about 3"), according to Dremel's international manual.
- Surface prep: Dremel's US40 manual says its surface prep wheels (US400 and US410) are not to be used with the Saw Max.
- Sturdier build: Dremel says the Ultra Saw's metal foot and guard resist the heat generated by heavy-duty jobs like grinding and cutting metal, and that its drive train lasts 3x longer than the Saw Max's.
Body & Power
Let's start from the construction. You want to see durability in a tool you invest a good sum of money in.
No arguing here: both tools are quite sturdy. They also share a similar design and ergonomics. Dremel lists the US40 at 13 inches long.
Dremel's published figures for the Saw Max, from before it was retired, were 6 amps and 17,000 RPM. Dremel rates the Ultra Saw US40 at 7.5 amps and 13,000 RPM. The cordless US20V runs off a 20V Max battery at 15,000 RPM.
Whatever the speed, Dremel's manuals say the speed rating of any wheel you mount must be equal to or greater than the tool's rated speed, and not to exceed the recommended wheel diameter.
Dremel also gives both Ultra Saws a soft start, which it says gradually increases speed for improved stability and control.
Here's Dremel's own video of the US40 Ultra Saw, replacing ceramic floor tile:
Video: Dremel. Dremel's chart rates its US540 diamond tile wheel for tile, and that wheel is sold separately from the US40-04 kit.
Projects & Materials you can work on
Dremel's US40 manual says the tool is intended for straight cuts in wood, plastic, metal, drywall, fiberboard and tile, using the applicable accessories recommended by Dremel. It has two wheel positions: a standard flat wheel for straight and plunge cuts, and an optional second position for flush cuts along flooring or against a wall.
The Ultra Saw also adds a function the Saw Max never had: surface preparation. Dremel lists two surface prep wheels for it, both sold separately from the US40-04 kit:
- US400 metal surface prep wheel: rust removal and paint removal from metal
- US410 concrete surface prep wheel (diamond embedded): thinset removal and paint removal from concrete and brick
Dremel's manual says the auxiliary handle is required with both. On the cordless US20V, Dremel's manual says surface preparation is for use only with the US410.
Dremel refers to the Ultra Saw as a 3-in-1 tool; I prefer to label it as your very own DIY treasure trove.
Cutting wheels & blade capacity
The Ultra Saw takes larger wheels than the Saw Max: up to 4", with a 3.5" metal cutting wheel in the kit. Dremel says the larger wheels provide fast cutting speeds and improved performance in a wide variety of materials.
These are abrasive wheels, not toothed blades. Dremel's US40 manual warns against attaching a saw chain, woodcarving blade, toothed saw blade or segmented diamond wheel with a peripheral gap greater than 10 mm, because such blades create frequent kickback and loss of control.
The US40-04 kit includes three cutting wheels, according to Dremel:
- US500 4" carbide wood cutting wheel: Dremel says it's intended to cut wood and other soft materials
- US600 4" carbide wood flush cutting wheel: for flush cutting of wood and other soft materials
- US510 3.5" metal cutting wheel: for a variety of materials such as metal and plastic
My original US40-01 kit also came with a surface prep wheel. The US40-04 doesn't list one, so get the US400 or US410 separately if you need it. The cordless US20V-01 kit comes with the US500, the US510 and the US540 diamond tile wheel, plus an edge guide, a dust port, one battery, a charger and a storage bag.
Here's which wheel Dremel's US40 manual rates for which material:
| Material (per Dremel) | Wheel |
|---|---|
| Wood: plywood, pine, poplar, oak, composite (OSB, fiberboard), laminate flooring; drywall; fiberglass | US500, or US600 for flush cuts |
| Metal: copper pipe, conduit, coated wire shelving, HVAC, aluminum sheet, gutter and fascia, galvanized sheet metal, threaded rod | US510 |
| Plastic: plexiglass, vinyl siding and gutter, PVC pipe | US500, US510 or US600 |
| Wall tile and floor tile | US540 diamond tile wheel |
| Brick fascia, cement board | US520 masonry wheel or US540 |
| Pavers | US520 masonry wheel |
Dremel describes the US520 as making score cuts in masonry and stone, and the US540 as cutting hard materials such as porcelain and tile and scoring brick and concrete. Both are sold separately from the US40-04 kit.
What hasn't changed is the maximum cutting depth. Dremel listed 3/4" (21.5 mm) for the Saw Max before retiring it, and lists the same for both Ultra Saws, which might not be optimal, depending on what materials you plan to work on.
Any significant downsides to the Ultra Saw?
There's no perfect tool, and this applies to Dremel's creations too.
The first downside is the 3/4" cutting depth I mentioned. For metal, Dremel's manual says the tool can do limited cutting on small stock such as copper pipe, conduit, rebar, threaded rod, coated wire shelving, HVAC, aluminum sheet, gutter and fascia. It also says not to attempt to cut large stock or sheets of metal, as the tool is not designed to be a dedicated cut-off machine.
For cuts deeper than the Ultra Saw's 3/4 inch, you need a full-size circular saw. I compare cordless tool brands in my DeWalt comparison and in my musings on Ridgid and Ryobi.
Second, you can't perform bevel cuts with the Ultra Saw. Dremel lists its maximum bevel capacity as 0 degrees.
And lastly, cords. I used to wish for some cord-free way to blaze through all of these materials, and Dremel now makes one: the cordless US20V, with the same 4" wheels and 3/4" cutting depth as the corded US40. You will need to charge and swap batteries, of course.
Safety with Dremel's compact saws
These are cutting tools, so here's what Dremel's US40 manual asks for:
- Keep the guard securely attached and positioned so the least amount of wheel is exposed towards you, and keep yourself and bystanders away from the plane of the rotating wheel.
- Always wear eye protection. Depending on the job, use a face shield, safety goggles or safety glasses; as appropriate, wear a dust mask, hearing protectors, gloves and a shop apron capable of stopping small abrasive or workpiece fragments.
- Hold the tool with both hands while starting it, and use the auxiliary handle, if provided, for maximum control over kickback or torque reaction during start-up.
- Never place your hand near the rotating accessory, and don't position your body in line with the wheel.
- Secure the workpiece in a vise, with clamps or on a stable platform; holding it by hand or against your body may lead to loss of control.
- Don't jam the wheel or attempt an excessive depth of cut, and support large panels near the line of cut and near the edge on both sides of the wheel.
- Use extra caution when making a pocket cut into existing walls or other blind areas, where the wheel may cut gas or water pipes or electrical wiring.
- Inspect wheels for chips and cracks before each use, and never set the tool down until the wheel has come to a complete stop.
The Final Verdict
With the Saw Max retired, the choice now is between the two Ultra Saws. The corded US40-04 is the one I compared here, with Dremel's 7.5 amp motor. If you'd rather skip the cord, the US20V-01 takes the same 4" wheels and cuts to the same 3/4" depth.