Quick Answer

When your core bit hits rebar in a wall, the cutting slows suddenly and the machine may kick. Do not force it — reduce feed pressure and let the diamond segments cut the steel slowly with full water cooling. A wet diamond core bit with a normal diamond bond cuts through standard rebar up to 20mm without changing tools, as long as you feed gently and keep the crown cool.

What Happens When the Bit Meets Rebar

• Cutting speed drops sharply and the machine vibrates.
• Without water, the steel heats the segments and accelerates wear.
• Forcing the bit can bend the spindle or shear the segments.
• A wandering hole starts if the crown grabs the rebar unevenly.

How to Drill Through Rebar Safely

• Scan the wall with a rebar detector first; mark the bar positions.
• Choose a drill point that avoids rebar if the layout allows.
• If unavoidable, drill with light, steady pressure — let the diamonds do the work.
• Keep water flowing continuously with a wet core drill bit; steel needs even more cooling than concrete.
• Lift the bit every 10-15 seconds in thick rebar to clear the flutes.
• If progress stops, check the crown for glazing and dress it with a dressing stone.

Choosing the Right Bit for Reinforced Walls

Rebar Diameter	Recommended Bit	Note
Up to 10mm	Standard wet core bit	Cuts through easily
10-20mm	Wet core bit, reduce feed	Cool well, slow and steady
20mm+ / dense mesh	Wet bit + gentle pressure	Consider repositioning the hole

Safety Tips

• Anchor the rig — rebar grabs create serious kickback torque.
• Wear gloves, eye protection and hearing protection.
• Check for electrical conduits in the wall before drilling.
• Never hold the machine by the bit or chuck area.

Frequently Asked Questions

Q: Will rebar destroy my core bit?

A: Not if you feed gently and keep water flowing. Steel dulls a bit faster than concrete, but a quality wet bit handles rebar routinely. Browse our diamond core drill bits built for reinforced concrete.

Q: Should I use a hammer drill to break the rebar first?

A:No — hammering disturbs the core and can jam the bit. Let the diamond crown cut the steel cleanly.

Q: How do I know I hit rebar vs a rock?

A: Rebar slows the cut evenly and the slurry may show metallic dust; rock usually causes vibration and glazing. Check with a rebar detector before drilling.

Conclusion

Scan first, avoid rebar when you can, and when you cannot — slow down, keep the water on and let the diamond do the cutting. JOY TECH supplies wet core bits that handle reinforced walls reliably; contact us for contractor and OEM pricing.