MS24693 : Mil-Spec Hardware
MS24693 : Mil-Spec Hardware Specification
Screw, Machine, Flat Countersunk Head, 100°, Cross Recessed, UNIC-2A and UNF-2A
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REQUIREMENTS:
1. MATERIAL:
Aluminum Alloy per 00-A-225/6. Brass per ASTM B16, ASTM B36, ASTM B134 or ASTM B206. Copper-Silicon Alloy per ASTM B48 or ASTM B39, USN C65100. UNS C85500 or UNS C66100. Nickel-Copper Alloy per ZZ-N-281, Type A (UNS ND4400). Carbon Steel Per Fed-STD-GG. Corrosion Resistant Steel per FED-STD-G6, Composition 302, 303, 304, 305, or 316 or equal to or interchangeable with 16-18 or 18-8 Chromium-Nickel Alloy Steel (developed for cold heading).
2. PROTECTIVE COATING, FLATING, OR TREATMENT:
Anodize in accordance with MIL-A-8625, Type I or II, Class 1, black chemical finish in accordance with MIL-F-495. Black Oxide coating in accordance with MIL-C-13924. Cadmium Plate in accordance with QQ-P-41G. Type II, Class 3, Nickel Plate in accordance with QQ-N-290, Class 1, Grade E. Clean and descale in accordance with ASTM A380.
3. MAGNETIC PERMEABILITY:
Corrosion resistant steel screws shall have a magnetic permeability in accordance with the procurement specification.
4. HEAT TREATMENT:
Aluminum Alloy screws, 62 KSI minimum ultimate tensile strength in accordance with MIL-H-6088.
5. RECESS:
The recess shall be in accordance with MS9006.
6. THREADS:
Threads shall be class 2A in accordance with FED-STD-H28/2 acceptability of screw threads shall be in accordance with FED-STD-H28/2D, System 21.
7. THREAD LENGTH:
For screws up to and including 2.000 inches in length, the complete threads shall extend to within two (2) threads of the bearing surface of the head, or closer if practicable. Screws of longer length shall have a minimum complete thread length of 1.750 inches.
8. UNTHREADED PORTION:
The diameter of the unthreaded portion of screws shall not be less than the minimum pitch diameter nor more than the maximum major diameter of the thread.
9. MATERIAL IDENTIFICATION:
Corrosion resisting steel screws with nominal sizes .11380 (#6) and larger shall be permanently marked with one dash (“–“). Marking shall be placed on top of head and indented. Method and size of marking shall conform to the requirements for permanent markings specified in SAE A5478.
10. POINTS:
Screws shall have plain sheared ends. Header points are acceptable in accordance with ANSI B18.6.3.
11. MATERIAL CODE:
- “A” Before dash number – Anodized, aluminum alloy screw.
- “B” Before dash number – Uncoated, brass screw.
- “BB” Before dash number – Black chemical finish, brass screw.
- “C” Before dash number – Cleaned and descaled, corrosion resistant steel screw.
- “CB” Before dash number – Cadmium plated, brass screw.
- “N” Before dash number – Uncoated, nickel-copper screw.
- “NB” Before dash number – Nickel plated, brass screw.
- “S” Before dash number – Cadmium plated, carbon steel screw.
- “U” Before dash number – Uncoated, copper-silicon screw.
- “8” After dash number – Black oxide coated, corrosion resistant steel screw.
12. PART NUMBER:
The part number shall consist of the basic MS number followed by material letter code. (See 12 above) followed by a dash number taken from Table II. Only one (1) dash number shall be used per part number. Do not use unassigned material codes or dash numbers.
- Part Number Examples:
- MS24693-A28 = Screw, machine, flat countersunk head, 100°, cross recessed, .1380-32 UNC-2A thread, anodized, aluminum alloy, .500 inch length.
- MS24693-B54 = Screw, machine, flat countersunk head, 100°, cross recessed, .1640-32 UNC-2A thread, uncoated, brass, 1.000 inch length.
- MS24693-BB80 = Screw, machine, flat countersunk head, 100°, cross recessed, .1900-24 UNC-2A thread, black chemical finish, brass, 1.500 inch length.
- MS24693-C202 = Screw, machine, flat countersunk head, 100°, cross recessed, .1120-48 UNC-2A thread, cleaned and descaled, corrosion resistant steel, .250 inch length.
- MS24693-CB132 = Screw, machine, flat countersunk head, 100°, cross recessed, .3125-18 UNC-2A thread, cadmium plated, brass, 3.000 inch length.
- MS24693-N254 = Screw, machine, flat countersunk head, 100°, cross recessed, .1640-36 UNF-2A thread, uncoated, nickel-copper alloy, 1.000 inch length.
- MS24693-NB106 = Screw, machine, flat countersunk head, 100°, cross recessed, .2500-20 UNC-2A thread, nickel plated, brass, 2.000 inch length.
- MS24693-S2 = Screw, machine, flat countersunk head, 100°, cross recessed, .1120-40 UNF-2A thread, cadmium plated, carbon steel, .250 inch length.
- MS24693-U154 = Screw, machine, flat countersunk head, 100°, cross recessed, .3750-18 UNF-2A thread, uncoated, copper-silicon alloy, 3.000 inch length.
- MS24693-2068 = Screw, machine, flat countersunk head, 100°, cross recessed, .1120-48 UNF-2A thread, black oxide coated, corrosion resistant steel, .500 inch length.
Notes:
- 1. All dimensions are in inches unless otherwise specified.
- 2. Unless otherwise specified, issues of referenced documents are those in effect at the time of solicitation.
- 3. In he event of a conflict between the text of this document and the references cited herein, the text of this document shall take precedence.
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