Bosch 1-1/4 in. StarlockPlus oscillating multi-tool bi-metal plunge cut blade

A familiar task made easier

The first time I snapped the Bosch StarlockPlus bi‑metal plunge blade onto my multi‑tool, the difference was immediate. The blade locked in with a reassuring click, no fiddling with pins or screws, and when I pulled the trigger, the usual high‑frequency buzz felt smoother and more planted than I’m used to with flat‑mount blades. That stability carried into the cut.

I’ve used a lot of oscillating blades for jobs that range from undercutting door jambs to freeing trim nails and cutting in for electrical boxes. This blade has settled into my kit as a generalist that handles those tasks without drama—and often with a cleaner result.

Setup and compatibility

This blade uses Bosch’s StarlockPlus interface, which is a three‑dimensional, closed‑back mount. On the right tool, it’s excellent: torque transfer feels direct, vibration is reduced, and blade changes are fast and tool‑free. The flip side is compatibility. If your oscillating multi‑tool uses open‑back “universal” or OIS‑style slotted blades, this won’t fit. You need a StarlockPlus or StarlockMax tool. That limitation is worth highlighting before you buy, because the interface is not cross‑compatible with older open‑back clamps.

The blade itself is 1‑1/4 in. wide with a 1.5 in. plunge depth. That depth covers common tasks—electrical cutouts, trimming shims, notching studs—but it is right at the limit of 2x stock. You can cut through nominal 2x lumber, though you’ll be working at full depth, so plan your approach to keep the kerf straight and avoid binding.

Cutting performance

Bosch pairs a bi‑metal cutting edge with their CurvedTec profile on the nose. The curve makes plunge starts more controllable and reduces the “walking” you can get when the teeth first hit the surface. In practice, I notice fewer chewed‑up entry points and a smoother transition into the cut, especially in harder woods and laminates. If you’ve ever tried to plunge into oak with a square‑nosed blade, you’ll appreciate this difference.

Speed is solid but not aggressive. On bare wood, this blade won’t match a Japanese‑tooth wood‑only blade for shear pace, but it leaves a cleaner kerf with less tear‑out, particularly across grain. I’ve used it for:

• Plunge cuts in 1/2 in. and 3/4 in. plywood to add vents and access panels
• Undercutting door casings and baseboard over tile and LVP
• Trimming cedar shims and composite shims flush with jambs
• Cutting out drywall for remodel boxes
• Nipping off protruding finish nails and brads during trim demo

In all those scenarios, the blade tracks well and resists deflection. Laser‑etched markings help orient the cut and gauge depth—handy when you don’t want to overshoot into hidden space. The finish on hardwoods is respectable. I get the cleanest results if I score the surface line with a knife first, and I tend to run the oscillation speed in the mid‑range to manage heat.

Nail and metal capability

The strength of a bi‑metal edge is versatility. I’ve hit embedded nails, cut through drywall screws in studs, and trimmed 1/2 in. copper stub‑outs without destroying the blade. It slows down in steel, as expected, but it keeps cutting and doesn’t shed teeth the way high‑carbon steel blades do. That said, there are limits. Hardened screws, stainless, or heavy gauge fasteners will wear the edge quickly. If you’re working in abrasive composites or doing a lot of metal, a carbide blade is the better choice. For mixed‑material remodeling—wood with the occasional fastener—this blade hits a sweet spot.

Control and vibration

The StarlockPlus mount is more than a convenience; it translates to better feel in the cut. Compared to flat‑interface blades on the same tool, I get noticeably less buzz in the handle and less chatter on the work surface. On delicate tasks like notching a cabinet back or shaving a sliver from a miter, that stability matters. It also reduces fatigue over longer sessions—something I appreciate when using the multi‑tool as a problem solver throughout a day.

The CurvedTec shape helps with control on plunge starts, but it also produces a smoother exit. When I cut outlet boxes in brittle plaster over lath, the blade was less prone to catching the edge and tearing the surface paper. Dust is still a reality—oscillating tools are not dust‑friendly—but with a steady hand and moderate speed the debris is predictable, and the cut lines stay clean.

Durability and heat management

Bi‑metal blades live longer than budget HCS blades, and this one follows that pattern. Across several days of remodel work—including oak flooring, MDF casing, and occasional nail encounters—it still cut cleanly. The edge eventually loses a bit of bite, and you’ll feel it first in denser material where feed slows. I’ve been able to extend life by letting the blade do the work: moderate oscillation speed, light pressure, and brief pauses to keep heat down. If you push hard at max speed, you’ll glaze the edge and scorch wood faster than you’d like.

The body resists discoloration better than many generics. I also appreciate the color‑coded interface and clear markings; they sound minor, but when you’re reaching into a crowded blade kit, quick identification saves time.

Ergonomics and visibility

Because the Starlock system sits closer to the tool’s nose than older mounts, the working length feels compact and rigid. That makes the blade easy to steer, though it also means you’re relying entirely on that 1.5 in. depth. For deep pockets or wide housings, I end up making overlapping plunges or switching to a longer blade. The 1‑1/4 in. width is a good middle ground—narrow enough to maneuver, wide enough to track straight. Visibility down the blade is decent; the curved nose lets you see the leading edge, which helps with accuracy on layout lines.

Where it shines

• Remodeling and repair with mixed materials
• Plunge cuts in wood and sheet goods where clean entry matters
• Undercutting trim and jambs for flooring
• Flush‑cutting nails and small diameter non‑ferrous pipe
• Situations where reduced vibration and better control help avoid collateral damage

What could be better

• Compatibility is limited to StarlockPlus and StarlockMax tools. If your multi‑tool uses slotted “universal” blades, this simply won’t mount.
• Cutting speed in wood is controlled rather than fast. For rapid demolition in clean lumber, a dedicated aggressive‑tooth wood blade is quicker.
• The 1.5 in. depth is right on the line for 2x stock; a longer option is useful to have alongside this one.
• Not the right choice for frequent hardened metal cuts; carbide remains king there.

Value

You can buy cheaper blades in bulk, but they dull quickly, especially when you hit metal. This Bosch bi‑metal blade costs more up front but earns its keep in consistency and lifespan. I measure value in the number of clean, predictable cuts I get before reaching for a replacement, and on that metric it performs well. The Swiss‑made build quality shows in the tooth uniformity and in how the blade holds together after hot cuts.

Recommendation

I recommend the Bosch StarlockPlus bi‑metal plunge blade for anyone running a StarlockPlus or StarlockMax multi‑tool who needs a reliable, general‑purpose cutter. It delivers smooth plunge starts, clean kerfs, and solid durability across the mixed‑material realities of remodel and repair work. The StarlockPlus mount reduces vibration and improves control, making it easier to cut accurately and with less fatigue. Be aware of the compatibility requirement and the 1.5 in. depth limit, and pair it with a carbide blade if hardened metal is on your menu. As a primary, do‑most‑tasks blade, it’s a dependable choice that earns a steady spot in my kit.