Bosch Starlock Oscillating Multi-Tool High-Carbon Steel Plunge Cut Blade

What I liked right away

I reached for this Bosch Starlock wood blade for a week of punch-list work: undercutting door casings for tile, plunging electrical box openings in plywood, and trimming back stubborn shims and casing. Right out of the package, the Swiss-made blade feels stout—0.13 in thick, 1.25 in wide, and 4 in long—with a curved cutting edge that hints at controlled plunge starts. The Starlock mount clicks into my multi-tool without drama, and the laser etching is clear enough that I don’t mix it up with metal- or drywall-rated blades in the pouch.

Fit, finish, and compatibility

Bosch’s Starlock interface is still my favorite for oscillating tools. The “drop-on” connection gives direct torque transfer and a noticeably tight, rattle-free feel compared with older slotted OIS blades. I ran this blade on a Starlock tool for most of my testing, then mounted it to a clamp-style OIS tool to check fit. It seated securely and tracked true on both. If your multi-tool is Starlock-only, you’re obviously covered. If it’s older OIS, make sure the clamp can bite the Starlock profile; most major brands I’ve used handle it fine. Either way, the color-coded interface and etching make it easy to grab the right blade in a hurry.

Design highlights that matter in use

• Curved-Tec cutting edge: The slightly arced profile does more than look nice. It reduces the “toe-in” snag you get on flat-nose blades and helps start plunge cuts with less chatter.
• 1.5 in immersion depth: A practical depth for most trim, casing, and 3/4 in sheet goods. It’s enough for light framing notches, but you’ll still want a longer blade if you’re burying into thick stock.
• Stout body: The blade’s thickness keeps it from chattering and wandering. The tradeoff is a little more heat if you force it; let the blade work and it stays clean and fast.

Plunge cuts and control

The curved edge is the star here. Starting a plunge cut into 3/4 in plywood felt precise—no skating, and the blade eased in without the chatter I get from flat-front profiles. On pine casing, the blade tracked straight down a pencil line, and I could feather the nose to nibble to the mark. For recessing outlet boxes in 1/2 in sheathing, I set the tool to a high oscillation speed, scored the outline, and then committed to the plunge. The entry was clean enough that my scribe lines were still sharp, which makes patch work that much faster.

On hardwoods (oak and maple), the blade still starts cleanly, but I needed to pace the cut and let chips clear. If you lean on it, heat builds, the cut line darkens, and the blade will glaze earlier than it should.

Cutting performance in different materials

• Pine, poplar, and soft trim: Quick, controllable cuts. Flush-trimming shims and jamb extensions was predictable and clean.
• Plywood and OSB: Plenty capable. In OSB specifically, I slowed down to reduce heat and avoided long continuous plunges; OSB’s resin can cook a blade if you push.
• Hardwood flooring and casing: Accurate, but speed drops. I got the best results on high oscillation speed with light feed pressure.
• Drywall: It’ll do it, but it’s overkill. A dedicated drywall blade makes less mess.
• Metals and cementitious materials: Not the job for this blade. It’s high-carbon steel, not bi-metal or carbide. If you hit a finish nail, expect tooth damage and a sudden drop in performance. For fiber-cement or lath, jump to carbide; for unknown nail situations, use bi-metal/carbide.

Bottom line: in wood, it’s a workhorse. In anything abrasive or ferrous, pick a different blade.

Vibration, noise, and feel

Starlock’s rigid mount pays dividends. With this blade installed, my tool ran smoother than with generic slotted blades—less buzzing in the handle and cleaner feedback through the cut. That translates into accuracy when you’re working close to finished surfaces. I noticed fewer “jump-outs” when undercutting door casings, and the saw marks at the entry point were minimal.

Durability and wear

In everyday wood tasks, the edge held up well. After a day of notching baseboards, trimming shims, and cutting a handful of outlet openings, the teeth were still sharp and the blade cut predictably. The fastest way to shorten its life is heat and metal. On a long plunge in oak, leaning too hard, I saw the telltale darkening on the kerf and the blade lost a step; a quick break to let it cool helped, but the cut speed never quite returned to “fresh blade” levels. And when I grazed a hidden 18-gauge brad, it was game over for the edge—still cuts, but slower and smokier. That’s consistent with HCS blades in general; it’s a wood blade, not a nail eater.

Accuracy and line of sight

The 1.25 in width is a nice middle ground—narrow enough for controlled corners, wide enough to keep a straight track in longer plunges. If you’re chasing tight curves or latticework, a narrower blade is better. For square cutouts, this one makes clean, straight sides with a manageable corner radius, and the curved nose helps “walk in” to a scribe line without gouging.

Maintenance and tips

• Let the blade do the work. High oscillation speed, light pressure, and occasional pauses to clear chips keep it cutting cool and fast.
• Score first on hardwoods. A shallow starter pass reduces tear-out and heat.
• Avoid unknowns. If there’s any chance of nails or screws, switch to a bi-metal or carbide blade.
• Keep it clean. A quick wipe to remove resin and dust preserves sharpness.

Value

As a single-pack, this blade sits in the premium tier, and the build quality reflects it. You’re paying for the Starlock mount, the controlled plunge profile, and tight manufacturing. If you’re doing frequent trim and carpentry cuts and you value smooth starts and low vibration, the price makes sense. If your work regularly hits fasteners, you’ll go through HCS blades quickly—spend the money on bi-metal or carbide instead and save yourself frustration.

Alternatives and when to choose them

• Bi-metal plunge blades: Slower in clean wood, but survive occasional nails. Good “unknowns” blade.
• Carbide plunge blades: The choice for fiber-cement, plaster, lath, and embedded grit. Overkill for softwood.
• Narrow wood blades (3/4 in): Better for tight corners and delicate trim, but less stable in long straight plunges.
• Japanese-tooth HCS: Faster in clean wood but can be grabby; the curved profile on this Bosch is calmer and more predictable.

The verdict

For clean, controlled plunge cutting in wood, this Bosch Starlock wood blade is excellent. The curved nose makes starts easy and reduces chatter, the Starlock mount keeps vibration low, and the blade’s stiffness inspires confidence when you’re notching baseboards or undercutting jambs against finished floors. In plywood and softwoods it’s quick; in hardwoods it’s accurate so long as you respect heat. Like every HCS blade, it’s the wrong tool for metal and abrasive siding, and it will punish you for hitting nails.

Recommendation: I recommend this blade to carpenters, remodelers, and DIYers who primarily cut wood and value precise, low-chatter plunge cuts—especially if you already run a Starlock tool. It’s a dependable, Swiss-made option for trim, cabinetry tweaks, and clean openings in sheet goods. If your work frequently encounters fasteners or abrasive materials, opt for a bi-metal or carbide blade instead to avoid premature dulling and save money in the long run.