Burnishing Tools and Machines

Burnishing Family

We are pleased to offer the widest array of standard burnishing products in the industry, supported by the broadest range of experience in application engineering and custom tool design. Let us provide you with burnishing solutions to meet your sizing and finishing needs, with faster production and at a lower cost.

Roller Burnishing Defined:

Roller burnishing is a surface finishing technique in which hardened, highly polished steel rollers are brought into pressure contact with a softer piece part.

As the pressure generated through the rollers exceeds the yield point of the piece-part material, the surface is plastically deformed by cold flowing of sub-surface material. The result is a mirror-like finish and a tough, work-hardened surface with load-carrying characteristics which make the burnished surface superior to finishes obtained by abrasive metal-removal methods.

Peak/Valley suface condition before and after roller burnishing.A roller burnished surface is smoother and more wear-resistant than an abraded surface of the same profilometer reading. Profilometers measure roughness height. Abrasive finishing processes remove metal by cutting or tearing it away, and while this usually lowers the roughness profile, it leaves sharp projections in the contact plane of the machined surface.

Roller burnishing displaces metal, rather than removing it. Material in microscopic “peaks” on the machined surface is caused to cold flow into the “valleys,” creating a plateau-like profile in which sharpness is reduced or eliminated in the contact plane. A burnished surface is therefore smoother than an abraded surface with the same roughness height measurement. The burnished surface will last longer under working conditions in contact with a mating part.

Roll-a-Finish Tools

Cogsdill Roll-a-Finish tools are applied to a wide variety of part configurations, including:

  • Inside diameters (holes)
  • Outside diameters (shafts)
  • Flat surfaces
  • Tapers
  • Spherical surfaces and contours
  • Fillets (radii at shoulders)

Standard Roll-a-Finish tools are available from stock for inside diameters from .187 to 4.000 inches (4.75 to 101.6mm), and for outside diameters from .062 to 2.000 inches (1.57 to 50.8mm). The tools are easily adjustable over a typical range of .040 inch (1.02mm). Special designs are available for larger and smaller diameters, and for tapers, faces, contours, and virtually any part configuration.

Bearingizing Tool

The Bearingizing Tool combines roller burnishing with peening action. As the tool is rotated at a high speed the rolls spin, rise, and fall over a cammed arbor, delivering up to 200,000 rapid fire blows per minute to the work surface. The peaks and valleys of the machined surface are compacted into a smooth, hardened, and ultra fine surface finish.

The Bearingizer may be the tool of choice where the following conditions exist:

  • Parts with thin walls
  • Parts with irregular wall thicknesses
  • Applications where porosity is an issue
  • Applications where very tight tolerances must be held

External Roller Burnishing Machines

Cogsdill’s CX machines roller burnish cylindrical diameters of any length in seconds.

Parts are sized, finished and work hardened by highly polished, precision rollers in one quick pass.

Fatigue life, corrosion resistance and appearance are enhanced as your parts are accurately sized and finished. Various model options are designed to meet your manufacturing requirements. Equipment options are available to accommodate through-feed applications, parts with obstructions, and part-to-part size variations.

Diamond Burnishing Tools

Precision tool for producing low microinch finishes on shafts or faces of any diameter, or on large bores.

  • Four designs allow use on most turning machines, manual or CNC
  • Replaceable, polished diamond insert
  • Adjustable for optimum burnishing pressure

Cogsdill Diamond Burnishing Tools are simple, efficient tools designed to produce mirror-like finishes on a wide range of ferrous and nonferrous part surfaces on most turning machines.

Set up and cycle times are short, even for unskilled operators. In all cases, the replaceable diamond insert can be changed quickly; on some models without removing the tool holder from the machine.