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Cross hole deburring

I was assigned the task of improving a hydraulic pump valve and bushing S/A. A large problem is keeping corners of cross holes in the bushing sharp. Wire brushes have been too tough and nylon brushes have been too soft. Can you offer any suggestions to deburr the I.D. of cross holes with dia. of .250"-.125" made from steel that will be hardened to HRC 40-45.

Nick Helms
- Jackson, MS
1999

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1999

When you say wire brushes, do you mean steel or SS? If so try brass. If that is too aggressive, try to find some with thinner wire or longer wire by having a thinner twisted wire center.

Last possibility, There are several companies that make a nylon (or similar) strand that is impregnated with abrasive. This is made into "brushes" just like wire ones. Here again, to aggressive by the operator and it fails. The abrasive is available in several different grits and grit densities as well as material.

James Watts
- Navarre, Florida

There are available on the market now, "ceramic fiber" brushes that will not round or break the edges of the hole.

Peter Marinkovic
- Whitewater, Wisconsin
2006

Try out the Orbitool at www.jwdone.com. Protective disk to protect the hole bore, and a carbide cutter under the disk to deburr your steel without a problem. Flexible shaft allows the carbide to deburr, and then flex the tool to ride on the disk to protect the surface.

Stan Kroll
- San Mateo, California, USA
2007