Multiple methods are available for deburring holes

Burrs present a hazard to those who handle parts during and after the manufacturing process.

Burrs can also break off in holes, causing significant problems. Deep oil holes in crankshafts, for example, must be burr-free to prevent small caps or slivers of material from entering the fluid system.

A burr can also have a negative impact on mating parts and how the fit and finish of components and assemblies look and perform.

There are five levels of burrs, plus one that goes beyond what is generally considered a burr. All images courtesy E-Z Burr Tool.

Customers demand that parts be smooth to the touch, aesthetically pleasing, have holes that are without burrs and, typically, have a nice looking chamfer.

When a hole is drilled, a burr is usually generated. The deburring method can have a major impact on cycle time, cost, quality and customer satisfaction.

In countries where labor costs are low and reducing cycle time is not critical, the most common way to deburr is with a manual scraping tool. These tools usually have a handle with replaceable blades. Hand scraping is time-consuming, but the tools are inexpensive.

However, repetitive use of these tools can increase the chance of long-term injuries, such as carpal tunnel syndrome. Cuts, too, are a reality, and the resulting edge consistency will not be as good, compared to an automated tool.

Out of Touch

When burrs are hard to access, such as those in the cross-holes of tubular components, there are more-efficient ways to deburr than by hand. Common methods include applying brushes, mounted points, sphere-shaped rotating tools, flexible abrasives and rotating tools with replaceable HSS or carbide blades or inserts.

Deburring tools can be used in high- and low-volume jobs and can be run on a wide range of equipment, including hand drills, drill presses, manual mills, CNC mills and lathes, and multitask machines.

Some deburring tools resemble one-piece tuning forks: a split design with two cutting “tines” that squeeze together to pass through a hole. In operation, the tool is inserted until it touches the rear of the hole, then on the retract feed it cuts the back of the burr.

The industry, however, offers a better alternative in the form of quick-change blades and inserts, which can be replaced in minutes or even seconds. These eliminate the need to remove the old-style tool and replace it or send it to the cutter grinding department for resharpening. In addition, quick-change designs are more accurate and robust. Some are even adjustable and allow the blades to be changed while the tool remains in the spindle.

When a burr is on a challenging workpiece material and hard to access, the long life and strength of a deburring tool that accepts carbide inserts can be the most cost-effective choice, especially for production applications. Inserts are available with aggressive cutting angles for difficult-to-deburr applications.

Long-reach tools and stubby lengths are readily available, too, and toolmakers can design and produce application-specific specials. For example, they can design tools with fixed pockets to accept chamfer inserts and combination tools to drill, deburr and chamfer in one pass.