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If you’re shopping for a cordless oscillating tool, you’ve probably got the BLACK+DECKER BDCOS20B and the DEWALT DCS356B on your radar. Both run on 20V batteries, but they take very different approaches — the BDCOS20B offers a 6-speed dial at 18,500 RPM, while the DCS356B uses a brushless motor hitting 20,000 OPM.
I’ve dug deep into the specs for both tools to help you pick the right one for your workshop. The real trade-off here is budget-friendly versatility versus pro-grade performance, and I’ll break down exactly who should buy which. Let’s get into it.
🏆 Quick Picks — My Top Recommendations
Best Overall: DEWALT DCS356B
Brushless motor delivers up to 57% more run time and hits 20,000 OPM — Check Price →
Runner-Up: BLACK+DECKER BDCOS20B
6-speed dial and comes with 8 sanding discs plus 3 blades included — Check Price →
Full Specs Comparison
| Specification | BLACK + DECKER 20V MAX Os | DEWALT 20V MAX XR Oscilla |
|---|---|---|
| Voltage | ✅ 20V | 20V |
| Power Source | Battery Powered | Battery Powered |
| Speed Settings | ✅ 6-speed | Variable |
| Motor Type | — | ✅ Brushless |
| LED Light | — | ✅ Yes |
| Accessory Change | ✅ Tool-free | — |
| Recommended Use | ✅ Grinding | — |
| Color | ✅ Black | — |
| Included Accessories | — | ✅ Two Wood Cutting Blades |
| Tool Only | ✅ Yes | ✅ Yes |
Individual Product Breakdown
I spent time digging through the specs, customer feedback, and real-world performance data for both of these 20V oscillating tools. Here’s my honest take on each one after comparing them side by side.
BLACK + DECKER 20V MAX Oscillating Tool (BDCOS20B)
20V | 18,500 RPM | 6-speed dial | LED light | Tool Only
- VERSATILE: Oscillating multi-tool ideal for a wide range of household...
- TOOL-FREE ACCESSORY CHANGE: One-handed tool-free quick blade change...
- VARIABLE SPEED: 6-speed dial to deliver precision performance that's right...
The BDCOS20B is a seriously solid budget-friendly option that surprised me with its included accessories — you get a wood blade, wood & metal blade, scraper blade, sanding platen, and 8 sanding discs right out of the box. The 6-speed dial gives you real precision control, letting you dial in from low speeds for sanding up to 18,500 RPM for cutting. It’s lightweight and designed for confined spaces, which makes it great for DIYers tackling household projects. The main downside is that it lacks the brushless motor tech of the DEWALT, so you won’t get the same runtime efficiency on a single charge.
✅ Pros
- 6-speed dial for precise speed control
- 8 sanding discs and 3 blades included
- Tool-free accessory change with one hand
- LED worklight illuminates dark work areas
❌ Cons
- Standard motor won’t match brushless runtime
- Lower max speed at 18,500 RPM vs 20,000 OPM
DEWALT 20V MAX XR Oscillating Multi-Tool (DCS356B)
20V | 20,000 OPM | Brushless motor | 3-speed | LED light
- The 3-speed selector of DEWALT 20V tools allows users to choose their speed...
- Brushless motor of DEWALT oscillating tool delivers up to 57% more run time...
- Dual-Grip variable speed trigger of DEWALT cordless tools gives users...
The DCS356B is the clear winner here thanks to its brushless motor, which DEWALT claims delivers up to 57% more runtime compared to brushed alternatives — that’s a huge deal when you’re working on extended projects. The 3-speed selector lets you choose between 0-13,000, 0-17,000, or 0-20,000 OPM, giving you solid flexibility across cutting, sanding, and grinding tasks. It also features a universal accessory adapter, so you can use blades from most major brands without any hassle. The dual-grip variable speed trigger gives you ultimate control, though it’s a bit heavier at 2.4 pounds compared to the BLACK+DECKER. It only includes two wood cutting blades in the box, which is less than the BDCOS20B’s accessory bundle.
✅ Pros
- Brushless motor delivers up to 57% more runtime
- Highest max speed at 20,000 OPM
- Universal accessory adapter works with most brands
- Quick-Change system without wrenches
❌ Cons
- Only includes 2 wood cutting blades in the box
- Heavier at 2.4 pounds
Which One Should You Buy?
After running through all the specs, I can tell you there’s no single “right” answer here — it really comes down to what you’re planning to tackle and how much runtime you need. Let me break down who each tool fits best.
BLACK + DECKER 20V MAX Oscillating Tool (BDCOS20B) is right for you if…
- You’re a weekend DIYer who wants everything included — 3 blades, a scraper, sanding platen, and 8 sanding discs right out of the box.
- You like having 6-speed dial control to fine-tune between delicate sanding and aggressive cutting up to 18,500 RPM.
- You work in tight spaces and want a lightweight tool that’s easy to maneuver in confined areas.
DEWALT 20V MAX XR Oscillating Multi-Tool (DCS356B) is right for you if…
- You need maximum runtime on the job — the brushless motor delivers up to 57% more run time compared to brushed motors.
- You want the highest cutting speed available at 20,000 OPM for tackling tougher materials.
- You already own DEWALT 20V batteries and want a tool that works with a universal accessory adapter for most blade brands.
❌ Who Should Skip All of These?
If you’re doing heavy demolition work or need a corded tool for marathon sessions without worrying about battery life, you’d be better served by a plug-in oscillating multi-tool. These cordless options are great for portability, but they won’t match the endless runtime of a corded unit for all-day professional use.
For most homeowners and DIYers, I’d say the DEWALT DCS356B is the smarter investment — that brushless motor and higher 20,000 OPM speed make it worth it for the long haul. But if you’re on a tighter budget and want accessories included, the BLACK+DECKER BDCOS20B gives you fantastic value for weekend projects.
Frequently Asked Questions
Which is better for cutting, the BLACK+DECKER BDCOS20B or the DEWALT DCS356B?
For cutting, I’d give the edge to the DEWALT DCS356B. It hits a higher max speed of 20,000 OPM compared to the BLACK+DECKER’s 18,500 RPM, which means faster cuts through wood and drywall. The brushless motor also maintains that speed more consistently under load, so you won’t feel it bog down as much on tougher materials.
Is the DEWALT DCS356B worth the extra money over the BLACK+DECKER BDCOS20B?
That depends on how often you’ll use it. The DEWALT’s brushless motor delivers up to 57% more runtime, which is a massive advantage if you’re doing multiple projects in one session. But the BLACK+DECKER comes with way more accessories included — 3 blades, a scraper, sanding platen, and 8 sanding discs — so if you’re a casual user, that included value might outweigh the DEWALT’s performance benefits.
Which multi-tool has better battery life?
The DEWALT DCS356B wins this one hands down. Its brushless motor is specifically designed to deliver up to 57% more run time over brushed motors, which is a huge difference when you’re working on extended projects. The BLACK+DECKER BDCOS20B uses a standard motor, so you’ll likely need a spare battery if you’re planning a full day of work.
Are both tools compatible with the same accessories?
Not exactly. The DEWALT DCS356B features a universal accessory adapter that works with most oscillating tool accessory brands, which is a big plus for flexibility. The BLACK+DECKER BDCOS20B uses its own quick-change clamping mechanism — it’s tool-free and easy to use, but you’re more limited to BLACK+DECKER-compatible accessories.
Which is lighter and easier to handle in tight spaces?
The BLACK+DECKER BDCOS20B is the better choice here. It’s specifically designed for use in confined spaces and is lightweight and ergonomic, making it easier to maneuver in awkward angles. The DEWALT is heavier at 2.4 pounds, which can get tiring during extended overhead work or in cramped areas.
Which tool has more speed settings for different tasks?
The BLACK+DECKER BDCOS20B offers a 6-speed dial, giving you more granular control over your speed for different materials and tasks. The DEWALT DCS356B has a 3-speed selector with 0-13,000, 0-17,000, and 0-20,000 OPM options, plus a variable speed trigger for finer control within each setting. If you want maximum precision, the BLACK+DECKER’s 6 speeds are better; if you want the highest top-end speed, the DEWALT wins.
My Final Verdict
The DEWALT DCS356B is my clear overall winner here. That brushless motor delivering up to 57% more runtime and the higher 20,000 OPM top speed make it the more capable tool for serious work — even if it costs a bit more upfront. The BLACK+DECKER BDCOS20B is still a fantastic runner-up for casual DIYers who want the included accessories and 6-speed dial control at 18,500 RPM.
If you’re still on the fence, ask yourself this: how often will you actually use it? If it’s a once-a-month tool for small projects, the BLACK+DECKER’s included blades and sanding discs make it unbeatable value. If you’re going to use it regularly and want it to last, the DEWALT’s brushless motor is worth every penny.
Best Overall: DEWALT DCS356B
- The 3-speed selector of DEWALT 20V tools allows users to choose their speed...
- Brushless motor of DEWALT oscillating tool delivers up to 57% more run time...
- Dual-Grip variable speed trigger of DEWALT cordless tools gives users...
Built for users who need maximum runtime and top-end speed at 20,000 OPM. The brushless motor delivers up to 57% more run time, making it the tool for regular, demanding work.
Runner-Up: BLACK+DECKER BDCOS20B
- VERSATILE: Oscillating multi-tool ideal for a wide range of household...
- TOOL-FREE ACCESSORY CHANGE: One-handed tool-free quick blade change...
- VARIABLE SPEED: 6-speed dial to deliver precision performance that's right...
Perfect for weekend DIYers who want everything included — 3 blades, scraper, sanding platen, and 8 sanding discs. The 6-speed dial at 18,500 RPM gives you solid control for household projects.
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