Metric Buttress (3°/30°) Screw Threads per DIN 513
DIN 513 Metric Buttress (3°/30°) Screw Threads
The S-series DIN 513 Metric Buttress (3°/30°) screw thread differs from the American buttress (7°/45°) screw thread and the British Buttress (7°/45°) screw thread in several ways, but the three most distinct ways are the screw thread flank angles, the use of millimeters instead of inches, and designation by pitch instead of threads-per-inch.
According to DIN 513:1985, Part 1, Page 4, Explanatory Notes: DIN 513 was presented to ISO as a potential standard Buttress screw thread form for the EC, but of several options presented, none were adopted as the one harmonized standard for the EC.
The S-series DIN 513 Metric Buttress Screw Thread has a 3° pressure angle and a 30° non-stressed angle. The Nominal Major Diameter and Pitch are specified in millimeters and use the same syntax as the M-series 60° screw thread designation.
The S-series DIN 513 Metric Buttress Screw Thread is designed in such a manner that the Major Diameter functions as a centralizing feature with limited clearance between the male and female screw threads.
The class-of-fit system uses the same Position and Grade system as the M-series Screw Threads. DIN 513 limits the selection of screw thread pitch diameter class-of-fit to seven designations: 7H; 8H; 9H; 7e; 8e; 8c; 9c. When the screw thread class-of-fit is not specified on the drawing, DIN 513 allows for the default class-of-fit to be 7H/7e. For the S-series screw thread these are considered the medium class-of-fit. Caution: The major and minor diameters of the S-series screw thread have their own class-of-fit parameters. For a full understanding of them you will have to read DIN 513.
Parts of DIN 513
DIN 513 is supplied in three individual parts, all purchased separately. No one part will give you enough information. All three are required. The three parts are: DIN 513 Part 1 Metric Buttress Threads; Thread Profiles DIN 513 Part 2 Metric Buttress Threads; General Plan
DIN 513 Part 3 Metric Buttress Threads; Deviations and Tolerances
This data is provided as a brief overview of the standard and for general information only. The intention is to provide accurate information; regardless; errors may exist in the supplied information. The actual standard contains much additional information. If accuracy is critical, base your final decisions on the data provided in the root document: DIN 513 (this data was taken from DIN 513:1985); which is a copyrighted document. To purchase a copy visit an Authorized Reseller.
Original Posting: 3/9/2011
Last Revision: 6/29/2011
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