Tube Deburring Tool

After cutting a tube, the cut edge has a burr; a sharp lip where the cutting wheel or hacksaw teeth pushed metal outward. The burr is a problem because it restricts flow inside the tube (for fluid-carrying tubes like hydraulic brake lines), it makes the tube hard to seat against a fitting (the burr won't pass through the fitting's bore), and it's a cut hazard for a mechanic handling the tube. The Tube Deburring Tool 363A removes both the inside and outside burr in one operation.

The 363A is small; about the size of a marker; but the working ends do the work the cutting wheel can't. One end has cutting blades sized for inside-of-tube deburring; the other handles outside-of-tube deburring. Both ends are made from special tool steel, oil-hardened, which means the cutting profile stays sharp through years of bike-shop use.

How to use it

After cutting a tube (with the Tube Cutter 360/6A or a hacksaw):

1. For the inside-of-tube burr: place the deburring tool's blade end inside the freshly cut tube and rotate. The blades shave the inside burr off in 1-3 rotations.
2. For the outside-of-tube burr: place the outside-deburring end over the tube and rotate the same way. Shorter cuts here; usually 1-2 rotations is enough.

The plastic housing with the ribbed surface gives finger grip during rotation. The cutting blades engage softer materials (aluminum, copper, brass tubing) easily; steel tubing takes a few more rotations.

Why a dedicated deburring tool vs. a file or sandpaper

A file can deburr the outside edge of a tube cleanly, but it can't reach the inside. A round file can reach inside if the tube is large enough, but the file leaves cross-hatched marks; the deburring tool leaves a smooth shaved edge. For tubing that needs to seat against a fitting at a precise dimension, the smooth shave is the better finish.

For brake-line work specifically (where the inner-tube edge has to seat against an olive or compression-fitting bore), the deburring tool is the right tool. A small inside-tube burr that survives an installation will cut into the olive on the first compression and create a leak.

Specs

• Inside and outside cutting blades
• Special tool steel, oil-hardened
• Plastic housing, ribbed for grip
• Article number: 363A

Built in Zreče, Slovenia

Unior has been forging hand tools in Zreče since 1919, and is the official technical partner of multiple World Tour and downhill teams. The 363A is part of Unior's broader tube-and-pipe service catalog, designed for the trades that work with hydraulic and pneumatic lines daily. The bicycle workshop's brake-line and accessory-tube work fits the same use case at the same quality.

Pro tip from our mechanics

The single best discipline for tube cutting in a bike shop: deburr immediately after the cut, not later. A burred tube that travels to the bench, gets bumped against the bench top, and then gets deburred has spent that time leaving sharp metal flakes inside the tube. Deburr at the cut, brush the chips out, then handle. Our workshop hand tools guide covers cutting, deburring, and the rest of the workshop hand-tool layer: Workshop hand tools every bike shop needs →