Bosch 1/16" Carbide Tipped 3-Wing Slotting Cutter Bit

Why I reached for this slotter

Slotting small, clean grooves in door stops and mouldings is one of those tasks that quickly exposes any weakness in a bit. I’ve been using Bosch’s 3-wing slotting cutter in the 1/16-inch kerf for weatherstripping, inlay, and edge details, and it’s become a predictable, low-drama option when I need tidy, repeatable slots.

For clarity, I’ll refer to it as the Bosch slotting cutter.

What you get

This is a three-wing, carbide-tipped cutter on a steel body with a 5/16-inch bore, designed to mount on a separate arbor (Bosch’s 92813C is the intended match). The cutter is 1-7/8 inches in diameter and produces a 1/16-inch kerf with up to a 1/2-inch depth of cut. That depth ceiling is generous for a slotter of this width and covers most common use cases: kerf-style weatherstripping, spline joints, T-molding slots, and decorative inlay channels.

The three-tooth layout is the main story here. Compared with two-wing slotters, the extra tooth reduces chip load per flute at a given feed rate, which tends to show up as a crisper wall and less chatter in hard stock. The carbide tips are well-brazed and even under magnification I didn’t see voids or sloppy joints—always a good sign for longevity and balance.

Setup and compatibility

A small but important reminder: this cutter is just the wheel—you’ll need a 5/16-inch arbor to use it. I ran it on a piloted arbor sized for my router’s collet, and I’d recommend using an arbor that accepts interchangeable bearings if you plan to control the offset from the edge by bearing size. The fit on the arbor’s 5/16-inch post was snug and concentric; there was no perceptible slop before tightening, which helps keep runout negligible.

On a handheld router, the piloted bearing makes sense for following profiles or edges. On a router table, I prefer a fence and featherboards and remove the bearing to keep things as compact as possible, especially for narrow mouldings. Either way, set your router speed responsibly. With a 1-7/8-inch diameter, the surface speed climbs quickly. I found 14,000–16,000 RPM to be a sweet spot for hardwoods with a moderate feed, and slightly faster for softer materials where burning is less likely.

Cut quality and performance

The Bosch slotting cutter puts down a very consistent kerf. On poplar door stops for kerf-in weatherstripping, my cuts measured 0.062–0.063 inches with calipers, tight enough to give a firm grip on standard barbed weatherstrip without crushing the fibers. In red oak and maple, the walls were clean with no fuzzing and only faint burnishing at slower feeds. MDF and primed finger-jointed trim cut effortlessly and produced a surprisingly clean slot edge with minimal fraying.

Three wings do their work here. Compared with a two-wing cutter I keep around for rough jobs, the Bosch left a noticeably smoother slot at the same feed rate, especially in end-grain passes on rail stock. Tear-out at the entry and exit was minimal; a short climb-cut nibble at the edge (followed by a conventional pass) eliminated it entirely when the grain was particularly cranky.

Chip evacuation matters with narrow kerfs. The small gullets can pack chips if your dust collection isn’t pulling or your feed is too tentative. With decent extraction at the fence and a steady feed, I didn’t have clogging issues. If you do, don’t speed up the router—speed up the feed or reduce RPM slightly to keep the chips larger and cooler.

Where it shines

• Kerf weatherstripping: The 1/16-inch kerf is spot-on for typical barbed weatherstrip. I cut dozens of linear feet in door stops, including painted stock, with predictable results.
• Thin splines and inlay: For aligning mitered picture frames or adding a narrow decorative line, the cutter produces uniform slots that accept shop-made 1/16-inch splines or veneer strips with just a touch of hand fitting.
• T-molding: Many T-molding barbs are designed around a 1/16-inch slot. The Bosch bit cut cleanly in MDF and plywood without widening the kerf or fuzzing the core.

Durability and wear

After a couple of projects across mixed materials, the carbide edges still feel sharp and the cut quality hasn’t drifted. I saw no chipped tips after hitting a couple of stray brads embedded in reclaimed trim (I don’t recommend that experience, but it happens). The brazing held, and balance remained good—no new vibration at speed. For a cutter you aren’t running hours a day in a production shop, the wear resistance seems more than adequate.

As always, longevity depends on heat. Keep your RPM and feed in a rational place, avoid lingering in the cut, and let dust collection do its part. Wipe pitch off the teeth when you see it; a quick clean keeps temperatures down and edges happier.

Limitations and gotchas

• Arbor requirement: You can’t use this without a 5/16-inch arbor. If you don’t already own one, factor in the cost and make sure the arbor you choose matches your router’s collet.
• Fixed kerf: Obvious, but worth saying—this is a 1/16-inch cutter. If you’re after a wider groove, you’ll need to stack cutters on a suitable arbor or buy the appropriate width.
• Heat in resinous softwoods: In pine with heavy resin, the third wing can encourage light burnishing if you feed too slowly. A small RPM reduction and a brisker feed fix it.
• Limited availability/returns: The version I evaluated was a closeout, limited-quantity item with a no-returns policy. That’s fine if you know what you’re buying; it’s less forgiving if you’re experimenting.

Tips for best results

• Use a router table for narrow or profiled stock. Featherboards above and against the fence keep the cut consistent and your hands clear.
• Take a shallow first pass when slotting brittle profiles or end grain, then follow with the full-depth cut.
• For exact kerf fit on inlay, plane your strips after a test cut. This bit’s kerf is consistent enough that a single setup yields interchangeable parts.
• Keep a sacrificial backer at the exit to prevent breakout on veneered plywood.
• Let the bearing lead the way only when the edge profile is clean and stable; otherwise, fence off the cut to avoid wandering.

Safety and compliance

It’s easy to forget that a slotting cutter presents a lot of exposed edge, especially on a table. Use guards and push sticks, keep the workpiece firmly supported, and don’t freehand near the spinning cutter. This product also carries a California Proposition 65 warning for exposure to chemicals including lead and/or wood dust. Work with dust extraction, wear a respirator when appropriate, and avoid handling dust with bare hands.

Value

As an individual cutter, it’s straightforward: good machining, clean cut quality, and carbide that holds up. The main value question is whether you already own a compatible arbor and, if not, whether you’ll use a slotter often enough to justify building out that little ecosystem. If you’re outfitting for weatherstripping or T-molding work, this 1/16-inch is a practical starting point.

Bottom line

The Bosch slotting cutter does exactly what I want a 1/16-inch slotter to do: cut precise, clean kerfs with minimal fuss across common trim materials. The three-wing design pays off in smoother walls and less chatter, and the carbide tips hold their edge sensibly well. Setup is straightforward if you’ve got the right arbor, and the 1/2-inch depth capacity is more than enough for most edge slots.

Recommendation: I recommend it. If your work includes kerf-style weatherstripping, T-molding, thin splines, or decorative inlay, this cutter delivers predictable results with a clean finish and sensible durability. Just ensure you have a compatible 5/16-inch arbor and be mindful of the closeout/non-returnable status when you purchase.