TO 1-1A-8

Table 2-20. NAS623 Pan Head, Short Thread, Machine Screw

THREAD DIAMETER HEAD HEIGHT MATERIAL STRENGTH

FIRST DASHNUMBER SIZE CLASS MIN MAX MIN MAX

TENSILESTRENGTH

SHEARSTRENGTH

-2 8-32 NC-2A .161 .163 .105 .115 1740 2005

-3 10-32 NF-3A .187 .189 .122 .133 2490 2690

-4 1/4-28 UNF-3A .247 .249 .162 .175 4520 4600

-5 5/16-24 UNF-3A .309 .312 .203 .218 7240 7300

-6 3/8-24 UNF-3A .372 .374 .244 .261 10,950 10,500

Code:

First dash number indicates screw diameter.

Second dash number indicates screw grip and length.

W after second dash number indicates Type I plating.

F preceding first dash number indicates Frearson recess.

Example of part number:

NAS623-4-10 = 1/4-inch diameter screw, .625 grip, Type II plating, Phillips recess.

NAS623F4-10W = 1/4-inch diameter screw, .625 grip, Type I plating, Frearson recess.

Material:

Steel, Military Specifications MIL-S-5000, MIL-S-5626, MIL-S-6049, or MIL-S-6098.

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