Cutting copper leaves a burr — a raised lip of metal rolled inward by the cutter wheel. It’s small, it’s easy to ignore, and leaving it there is one of the quietest ways to shorten the life of a system you just built. Here’s what the burr actually does and the tool that removes it in two seconds.
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Why the burr matters more than it looks
A tubing cutter works by rolling a wheel around the pipe under pressure. That displaces metal, and some of it curls into the bore. The result is a ridge sticking into the water path at every single joint.
Two things follow from that. First, turbulence: water hits the ridge and swirls instead of flowing smooth. On a copper system this is the classic setup for erosion-corrosion — the turbulent flow scours the pipe wall just downstream of the joint, and years later you get a pinhole that looks random but isn’t. Second, on soldered joints the burr can interfere with how the pipe seats and how solder draws into the gap.
The fix takes seconds. That asymmetry — two seconds now versus a pinhole leak later — is the entire argument.
Inner and outer, not just inner
Cutting rolls metal both ways: a burr inward into the bore, and often a raised edge outward on the pipe end. The inner burr is the flow problem; the outer edge is the fit problem, because it can stop the pipe from seating fully in a fitting socket and can nick an O-ring on push-to-connect fittings.
So the tool you want does both — a reamer for the inside and a chamfer for the outside.
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The two worth owning
- RIDGID 223S inner/outer reamer (1/4″–1-1/4″) — the trade standard. Handles copper and stainless tubing, does inside and outside, and its 45 cutting edges mean it stays sharp through a lot of joints.
- WISSCOOL inner/outer reamer (1/4″–1-5/8″) — a wider size range and it chamfers plastics (PVC, PPR) as well as copper, brass, and aluminum. Handy if your work isn’t copper-only.
Most tubing cutters have a folding triangular reamer blade built into the body, and that works — it’s better than nothing by a mile. But it’s awkward on larger sizes, it dulls, and it tends to gouge if you lean on it. A dedicated reamer gives you a cleaner, more even cut edge with less effort.
How to use it (without making it worse)
- Point the pipe down so shavings fall out instead of into the line. Copper chips left in a system end up in a cartridge or an aerator later.
- Light pressure, steady rotation. You’re shaving the lip off, not machining a chamfer. Heavy pressure thins the pipe wall right where it needs strength.
- A couple of turns is enough. Run a fingertip inside the end — smooth means done.
- Do the outside too, then clean and flux if you’re soldering. See solder and flux for copper.
It matters for every joining method
People assume deburring is a soldering thing. It isn’t:
- Press fittings seal on an O-ring inside the fitting. A sharp outer edge can nick that O-ring as the pipe goes in — a leak you won’t find until it’s pressed. See copper press fittings.
- Push-to-connect — same O-ring problem, plus a burr can catch the grab ring.
- Soldered joints — the pipe needs to bottom out squarely in the socket for capillary action to fill the gap.
Start with a square cut in the first place: the pipe cutter guide covers what actually cuts clean.
FAQ
Do I really need to deburr copper pipe?
Yes. The inner burr creates turbulence that drives erosion-corrosion over time, and the outer edge can prevent the pipe from seating properly or damage an O-ring. It takes seconds and prevents problems that surface years later.
Can I just use the reamer on my tubing cutter?
It works, and it beats skipping the step. A dedicated inner/outer reamer is faster, more even, and much easier on larger sizes — and it does the outside edge properly, which the folding blade doesn’t.
What happens if I don’t deburr?
Often nothing you’d notice right away — which is why the step gets skipped. Over years, turbulent flow past the ridge can erode the pipe wall just downstream of the joint, and on press or push-fit connections a sharp edge risks damaging the sealing O-ring during assembly.
For the plumbers reading this
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Related guides
- Best pipe cutters
- Best solder and flux for copper pipe
- Best copper press fittings
- Best plumbing torches
Related: the burr is worse when the cut itself walked — see tubing cutter cutting crooked.
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