SDS-Plus RX4 4-Cutter Concrete Drill Bit

The SDS-Plus RX4 4-cutter concrete drill bit by Milwaukee — a full-carbide 4-cutter head built for fast, accurate drilling in reinforced concrete and masonry.

SDS-Plus shank4-cutter carbide headReinforced concreteMasonry & stoneFast drillingMilwaukee RX4

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SDS-Plus 4-cutter concrete drill bits: the complete guide

Everything you need to know about the SDS-Plus RX4 4-cutter concrete drill bit — from the cutting geometry, through correct use, all the way to drilling in heavily reinforced concrete. This guide was written by the experts at Adit Ltd.

What is a 4-cutter drill bit and why does it matter?

A 4-cutter drill bit carries four carbide cutting edges on the head instead of the two found on a conventional bit. The four edges share the load, so each edge does less work per rotation. The result is a rounder, more accurate hole, less wandering at the start, and a bit that keeps drilling straight even when it touches steel reinforcement inside the concrete.

The SDS-Plus RX4 pairs this 4-cutter head with an SDS-Plus shank, so it locks into any standard SDS-Plus rotary hammer and transfers the full percussion energy of the tool straight to the concrete.

The cutting principle:

Under hammer action the four carbide tips crush the concrete ahead of the bit, while the wide helical flutes clear the dust up and out of the hole. Clean flutes keep the tips cutting fresh material instead of grinding through their own dust, which is what keeps drilling fast and the tips cool.

How to drill with the SDS-Plus RX4

1. Match the mode — set the rotary hammer to hammer-drilling (percussion) mode; the RX4 is built for impact drilling, not rotation only.
2. Start square — hold the tool perpendicular to the surface and let the four cutters find their bite before applying full pressure.
3. Steady feed — apply firm, even pressure and let the hammer do the work; forcing the bit does not drill faster and heats the carbide.
4. Clear the dust — withdraw the bit a little every so often so the flutes carry the dust out and the hole stays clean.
5. Clean the hole — brush and blow out the finished hole before setting an anchor or injecting adhesive.

Advantages of the 4-cutter RX4

• Straight, round holes: four cutting edges centre the bit and reduce wandering, giving a hole that matches the anchor for a tight, reliable set.
• Handles rebar: the 4-cutter head is far less likely to be deflected or damaged when it meets reinforcement, so the bit keeps its line.
• Fast drilling: load shared across four tips plus wide dust flutes keeps the drilling rate high hole after hole.
• Long carbide life: sharing the cutting work across four edges spreads the wear and extends the working life of the bit.
• Standard SDS-Plus fit: works with any SDS-Plus rotary hammer already on site — no special tool needed.

Frequently asked questions