A-A-51203
27 November 1985
COMMERCIAL ITEM DESCRIPTION
BUR, DENTURE TRIMMING, (High Speed Tool Steel)
The General Services Administration has authorized the use of this commercial item description in preference to Federal Specification GG-B-823C.
This commercial item description covers a denture trimming bur used for furnishing dentures in prosthetic laboratory procedures.
Salient characteristics:
The bur shall be made of AISI type M2 high speed tool steel. The bur shape shall be as shown in figure 1. The overall length shall be 1-3/4 ± 1/8 inch, the shank diameter shall be 0.0924 ± 0.0005 inch, the number of blades shall be 12 ± 1, the head diameter at largest diameter shall be 0.188 ± 0.005 inch and the length of the head shall be 27/64 ± 1/64 inch. The bur shall be a denture trimming bur, suitable for use with a straight handpiece in finishing plastic denture materials in prosthetic laboratory procedures. The bur shall be furnished as specified. The bur shall be one-piece construction, and shall consist of a shank and a head. The shank of the bur shall be straight. The blades of the bur head shall be shaped and sharpened to cut at the tip as well as the sides for the bur head, and provide automatic chip clearance.
Runout. The total indicated runout of the burs shall not exceed 0.005 inch, when tested as specified in test section under runout.
Hardness. The head and shank of the burs shall have a minimum Rockwell hardness of C62, when tested in accordance with ASTM E-18 (Rockwell) of E-92 (Vickers or Diamond pyramid).
Fatigue in cutting. The time required to cut the eighteenth half-inch shall not be more than 2.25 the time that is required to cut the second half-inch, when tested as specified in test section under fatigue in cutting. The burs shall show no bending as a result of these tests.
Finish. The bur shall have a black oxidized finish. The shank of the bur shall be smoothly finished.
Marking. Marking of the bur with the name or trademark shall be at the option of the supplier.
Workmanship. The bur shall be free from defects which may detract from its appearance and impair its serviceability.
Unit. Package (PG). One package containing twelve burs, as specified, constitutes one unit. The package shall be so designed that each bur is contained in an individual cell.
DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.
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