AN363/MS21045 all metallic locking steel nut (full height)
Full height nut designed for tension applications, limited to a maximum temperature of 450 oF.
MS21045 specification options:
‘L’ for Lubricated steel
‘-’ for un-lubed steel
‘C’ for Stainless
Size designation -04 through -08 for #4 to #6, and -3 through -12 for 3/16” to 3/4” diameters in 1/16” increments. Coarse thread for #6 and #8 sizes fine thread for #10 and larger.
Current Specification: NASM21045 for steel and stainless, but limited to 400 oF, NASM21046 for Stainless limited to 800 oF (still uses MS number for part number)
Example: MS21045-3 is a 3/16” steel nut with metallic locking device.
Common substitutions:
Old number |
New number |
Thread size |
Material |
Height (max) |
Wrench size |
AN363-632 |
MS21045-06 |
6-32 |
STEEL |
.188 |
5/16” |
AN363-832 |
MS21045-08 |
8-32 |
STEEL |
.250 |
11/32” |
AN363-1032 |
MS21045-3 |
10-32 |
STEEL |
.250 |
3/8” |
AN363-428 |
MS21045-4 |
1/4-28 |
STEEL |
.328 |
7/16” |
AN363-524 |
MS21045-5 |
5/16-24 |
STEEL |
.360 |
½” |
AN363-624 |
MS21045-6 |
3/8-24 |
STEEL |
.469 |
9/16” |
AN363-632 |
MS21045C06 |
6-32 |
STAINLESS |
.188 |
5/16” |
AN363-832 |
MS21045C08 |
8-32 |
STAINLESS |
.250 |
11/32” |
AN363C1032 |
MS21045C3 |
10-32 |
STAINLESS |
.250 |
3/8” |
AN363C428 |
MS21045C4 |
1/4-28 |
STAINLESS |
.328 |
7/16” |
AN363C524 |
MS21045C5 |
5/16-24 |
STAINLESS |
.360 |
½” |
AN363C624 |
MS21045C6 |
3/8-24 |
STAINLESS |
.469 |
9/16” |
MS21046 all metallic locking silver plated stainless steel nut (full height, high temp)
Full height nut designed for tension applications, limited to a maximum temperature of 800 oF.
Size designation -04 through -08 for #4 to #6 and -3 through -12 for 3/16” to 3/4” diameters in 1/16” increments. Coarse thread for #6 and #8 sizes fine thread for #10 and larger.
Current Specification: NASM21046 for Stainless limited to 800 oF (still uses MS number for part number)
Example: MS21046-3 is a 3/16” steel nut with metallic locking device.
Common substitutions:
Number |
Thread size |
Material |
Height (max) |
Wrench size |
MS21045C06 |
6-32 |
STAINLESS |
.188 |
5/16” |
MS21045C08 |
8-32 |
STAINLESS |
.250 |
11/32” |
MS21045C3 |
10-32 |
STAINLESS |
.250 |
3/8” |
MS21045C4 |
1/4-28 |
STAINLESS |
.328 |
7/16” |
MS21045C5 |
5/16-24 |
STAINLESS |
.360 |
½” |
MS21045C6 |
3/8-24 |
STAINLESS |
.469 |
9/16” |
AN364/MS20364/MS21083 non-metallic locking steel nut (low height)
Low height nut designed for shear applications, limited to a maximum temperature of 250 F. Nylon insert lock nuts are designed for one use only, locking strength is greatly reduced when removed.
MS21083 specification options:
The materials can be Aluminum (D), Steel (N), Brass (B), or Stainless (C)
Size designation 02, 04,06, 08 are machine screw sizes coarse thread, and -3 through -20 for 3/16” to 1 1/4” diameters in 1/16” increments fine Thread.
Current Specification: NASM21083 (still uses MS21083 for part number)
Example: MS21083N3 is a 3/16” steel nut with non-metallic locking insert.
Common substitutions:
Old number |
New number |
Thread size |
Material |
Height (max) |
Wrench size |
AN364-632 |
MS21083N06 |
6-32 |
STEEL |
.141 |
5/16” |
AN364-832 |
MS21083N08 |
8-32 |
STEEL |
.188 |
11/32” |
AN364-1032 |
MS21083N3 |
10-32 |
STEEL |
.188 |
3/8” |
AN364-428 |
MS21083N4 |
¼-28 |
STEEL |
.219 |
7/16” |
AN364-524 |
MS21083N5 |
5/16-24 |
STEEL |
.266 |
½” |
AN364-624 |
MS21083N6 |
3/8-24 |
STEEL |
.282 |
9/16” |
AN364-632C |
MS21083C06 |
6-32 |
STAINLESS STEEL |
.141 |
5/16” |
AN364-832C |
MS21083C08 |
8-32 |
STAINLESS STEEL |
.188 |
11/32” |
AN364-1032C |
MS21083C3 |
10-32 |
STAINLESS STEEL |
.188 |
3/8” |
AN364-428C |
MS21083C4 |
¼-28 |
STAINLESS STEEL |
.219 |
7/16” |
AN364-524C |
MS21083C5 |
5/16-24 |
STAINLESS STEEL |
.266 |
½” |
AN364-624C |
MS21083C6 |
3/8-24 |
STAINLESS STEEL |
.282 |
9/16” |
AN365/MS20365/MS21044 non-metallic locking steel nut replaced by MS21044 series.
Full size nut designed for tension (axial) applications, limited to a maximum temperature of 250 F. Nylon insert lock nuts are designed for one use only, locking strength is greatly reduced when removed.
MS21044 specification options:
The materials can be Aluminum (D), Steel (N), Brass (B), or Stainless (C)
Size designation 02, 04,06, 08 are machine screw sizes coarse thread, and -3 through -20 for 3/16” to 1 1/4” diameters in 1/16” increments fine Thread.
Current Specification: NASM21044 (still uses MS21044 for part number)
Example: MS21044N3 is a 3/16” steel nut with non-metallic locking insert.
Common substitutions:
Old number |
New number |
Thread size |
Material |
Height (max) |
Wrench size |
AN365-440 |
MS21044N04 |
4-40 |
STEEL |
.157 |
¼” |
AN365-632 |
MS21044N06 |
6-32 |
STEEL |
.188 |
5/16” |
AN365-832 |
MS21044N08 |
8-32 |
STEEL |
.250 |
11/32” |
AN365-1032 |
MS21044N3 |
10-32 |
STEEL |
.250 |
3/8” |
AN365-428 |
MS21044N4 |
¼-28 |
STEEL |
.328 |
7/16” |
AN365-524 |
MS21044N5 |
5/16-24 |
STEEL |
.360 |
½” |
AN365-624 |
MS21044N6 |
3/8-24 |
STEEL |
.469 |
9/16” |
AN365-440C |
MS21044C04 |
4-40 |
STAINLESS STEEL |
.157 |
¼” |
AN365-632C |
MS21044C06 |
6-32 |
STAINLESS STEEL |
.188 |
5/16” |
AN365-832C |
MS21044C08 |
8-32 |
STAINLESS STEEL |
.250 |
11/32” |
AN365-1032C |
MS21044C3 |
10-32 |
STAINLESS STEEL |
.250 |
3/8” |
AN365-428C |
MS21044C4 |
¼-28 |
STAINLESS STEEL |
.328 |
7/16” |
AN365-524C |
MS21044C5 |
5/16-24 |
STAINLESS STEEL |
.360 |
½” |
AN365-624C |
MS21044C6 |
3/8-24 |
STAINLESS STEEL |
.469 |
9/16” |
MS21042 Low profile all steel locking nut
Low height nut designed for shear applications, however is still stronger in tension than the AN365/MS21044 series limited to a maximum temperature of 450 F.
MS21042 specification options:
‘L’ in part number Dry film lube (preferred)
‘-’ In part number, not dry film lubricated can be used instead of lubed ones, may be slightly harder to turn.
Size designation 02, 04, 06, 08 are machine screw sizes coarse thread, and -3 through -6 for 3/16 to 3/8” diameters in 1/16” increments fine Thread.
Current Specification: NASM21042 (still uses MS21042 for part number)
Example: MS21042L3 is a 3/16” steel locking nut with dry film lube. MS20142-3 no lube.
Number |
Thread size |
Material |
Height (max) |
Wrench size |
MS21042L06 |
6-32 |
Steel |
.141 |
3/16” |
MS21042L08 |
8-32 |
Steel |
.188 |
7/32” |
MS21042L3 |
10-32 |
Steel |
.188 |
1/4” |
MS21042L4 |
¼-28 |
Steel |
.219 |
5/16” |
MS21042L5 |
5/16-24 |
Steel |
.266 |
3/8” |
MS21042L6 |
3/8-24 |
Steel |
.282 |
7/16” |
MS21043 Low profile all silver plated stainless steel locking nut (High temp)
Low height nut designed for shear applications, However is still stronger in tension than the AN365/MS21044 series limited to a maximum temperature of 800 F.
MS21043 specification options:
Size designation 02, 04,06, 08 are machine screw sizes coarse thread, and -3 through -6 for 3/16 to 3/8” diameters in 1/16” increments fine Thread.
Current Specification: NASM21043 (still uses MS21043 for part number)
Example: MS21043L3 is a 3/16” steel locking nut with dry film lube. MS20143-3 no lube.
Number |
Thread size |
Material |
Height (max) |
Wrench size |
MS21043-06 |
6-32 |
Steel |
.141 |
3/16” |
MS21043-08 |
8-32 |
Steel |
.188 |
7/32” |
MS21043-3 |
10-32 |
Steel |
.188 |
1/4” |
MS21043-4 |
¼-28 |
Steel |
.219 |
5/16” |
MS21043-5 |
5/16-24 |
Steel |
.266 |
3/8” |
MS21043-6 |
3/8-24 |
Steel |
.282 |
7/16” |
AN310 Castle nut, usually cad plated steel used mainly with cotter pins
Full Height nut designed for drilled shank bolts, clevis bolts. Full height nuts are designed for tension applications. Slots are designed to take cotter pins for safety. Cotter pins are recommended whenever a nut may have a rotational force applied to it.
The materials can be Aluminum (D), Steel (-) or Stainless (C)
Size designations are -3 through-20, and are fine threads, diameter is listed in 1/16” increments. (-3 is 3/16”, -4 is ¼”)
Current specification: NASM310 (still uses AN310 for part number)
Example: AN310-3 is cad plated steel nut for 3/16” bolt
AN310C3 is stainless steel nut for 3/16” bolt
Steel number |
Stainless number |
Thread size |
Height (max) |
Wrench size |
AN310-3 |
AN310C3 |
10-32 |
.250 |
3/8” |
AN310-4 |
AN310C4 |
¼-28 |
.281 |
7/16” |
AN310-5 |
AN310C5 |
5/16-24 |
.328 |
½” |
AN310-6 |
AN310C6 |
3/8-24 |
.406 |
9/16” |
AN310-8 |
AN310C8 |
1/2-20 |
.563 |
3/4” |
AN310-12 |
AN310C12 |
3/4-16 |
.813 |
1 1/8” |
AN315 Full height check nut, usually cad plated steel used mainly as locking device for plain nuts or rod ends
These nuts have no self-locking device, and are used to lock other nuts or rod ends by being tightened against the object that needs to be locked.
The materials can be Aluminum (D), Steel (-) or Stainless (C)
Size designations are -3 through-20, and are fine threads, diameter is listed in 1/16” increments. (-3 is 3/16”, -4 is ¼”)
An R behind the number designates Right hand thread (common), an L designates Left hand thread.
Current specification: NASM315 (still uses AN315 for part number)
Example: AN315-3R is cad plated steel nut for 3/16” bolt right hand thread
AN315C3R is stainless steel nut for 3/16” bolt right hand thread
Steel number |
Stainless number |
Thread size |
Height (max) |
Wrench size |
AN315-3R |
AN315C3R |
10-32 |
.140 |
3/8” |
AN315-4R |
AN315C4R |
¼-28 |
.188 |
7/16” |
AN315-5R |
AN315C5R |
5/16-24 |
.234 |
½” |
AN315-6R |
AN315C6R |
3/8-24 |
.281 |
9/16” |
AN315-8R |
AN315C8R |
1/2-20 |
.375 |
3/4” |
AN315-12R |
AN315C12R |
3/4-16 |
.625 |
1 1/8” |
AN316 Half height check nut, usually cad plated steel used mainly as locking device for plain nuts or rodends
These nuts have no self-locking device, and are used to lock other nuts or rod ends by being tightened against the object that needs to be locked.
The materials can be Steel (-) or Stainless (C)
Size designations are -3 through-20, and are fine threads, diameter is listed in 1/16” increments. (-3 is 3/16”, -4 is ¼”)
An R behind the number designates Right hand thread (common), an L designates Left hand thread.
Current specification: NASM316 (still uses AN316 for part number)
Example: AN316-3R is cad plated steel nut for 3/16” bolt right hand thread
AN316C3R is stainless steel nut for 3/16” bolt right hand thread
Common sizes
Steel number |
Stainless number |
Thread size |
Height (max) |
Wrench size |
AN316-4R |
AN316C4R |
¼-28 |
.125 |
7/16” |
AN316-5R |
AN316C5R |
5/16-24 |
.156 |
½” |
AN316-6R |
AN316C6R |
3/8-24 |
.188 |
9/16” |
AN316-8R |
AN316C8R |
1/2-20 |
.250 |
3/4” |
AN316-12R |
AN316C12R |
3/4-16 |
.375 |
1 1/8” |
AN320 Half height Castle nut, usually cad plated steel used mainly with cotter pins
Half Height nut designed for drilled shank bolts, clevis bolts. Half height nuts are designed for shear applications and have half the tension strength of full height AN310 nuts. Slots are designed to take cotter pins for safety. Cotter pins are recommended whenever a nut may have a rotational force applied to it.
The materials can be Aluminum (D), Steel (-) or Stainless (C)
Size designations are -3 through-20, and are fine threads, diameter is listed in 1/16” increments. (-3 is 3/16”, -4 is ¼”)
Current specification: NASM320 (still uses AN320 for part number)
Example: AN320-3 is cad plated steel nut for 3/16” bolt
AN320C3 is stainless steel nut for 3/16” bolt
Common sizes
Steel number |
Stainless number |
Thread size |
Height (max) |
Wrench size |
AN320-3 |
AN320C3 |
10-32 |
.188 |
3/8” |
AN316-4 |
AN316C4 |
¼-28 |
.188 |
7/16” |
AN316-5 |
AN316C5 |
5/16-24 |
.188 |
½” |
AN316-6 |
AN316C6 |
3/8-24 |
.219 |
9/16” |
AN316-8 |
AN316C8 |
1/2-20 |
.250 |
3/4” |
AN316-12 |
AN316C12 |
3/4-16 |
.375 |
1 1/8” |
MS35649, AN340 Plain Hex nut (non-locking)
These nuts have no self-locking device, and are used to lock other nuts. Sometimes used on ground studs or other avionics, typically not used in structural applications. Course threads only.
The materials can be Steel, Stainless , Brass, or Copper Silicon Alloy
Size designations are shown in the table below
Current specification: NASM35649 (still uses MS35649 for part number)
Example: MS35649-242 is a cad plated steel nut for 4-40 thread.
MS35649-244 is a stainless steel nut for 4-40 thread.
Common sizes
MS35649 Dash Number |
AN340 Dash number |
Material |
Thread size |
Height (max) |
Wrench size |
MS35649-242 |
AN340-4 |
Steel |
4-40 |
.098 |
¼” |
MS35649-262 |
AN340-6 |
Steel |
6-32 |
.114 |
5/16” |
MS35649-282 |
AN340-8 |
Steel |
8-32 |
.130 |
11/32” |
MS35649-202 |
AN340-10 |
Steel |
10-24 |
.130 |
3/8” |
MS35649-2252 |
AN340-416 |
Steel |
¼-20 |
.193 |
7/16” |
MS35649-244 |
AN340C4 |
Steel |
4-40 |
.098 |
¼” |
MS35649-264 |
AN340C6 |
Steel |
6-32 |
.114 |
5/16” |
MS35649-284 |
AN340C8 |
Steel |
8-32 |
.130 |
11/32” |
MS35649-204 |
AN340C10 |
Steel |
10-24 |
.130 |
3/8” |
MS35649-2254 |
AN340C416 |
Steel |
¼-20 |
.193 |
7/16” |
