AN935, MS35338 Split lock washers
Split lock washers are typically used to lock non-structural hardware, typically electrical/avionics items. For structural items, self-locking hardware is preferred.
Current spec: NASM35338 (still uses MS35338 for part number)
Commonly used sizes
Nominal size |
Steel |
|
|
|
|
Old |
New |
Stainless Steel |
OD |
Thickness |
|
#6 (.138) |
AN935-6 |
MS35338-41 |
MS35338-136 |
.250 |
.031 |
#8 (.164) |
AN935-8 |
MS35338-42 |
MS35338-137 |
.293 |
.040 |
#10 (.190) |
AN935-10 |
MS35338-43 |
MS35338-138 |
.334 |
.047 |
1/4” |
AN935-416 |
MS35338-44 |
MS35338-139 |
.487 |
.062 |
5/16” |
AN935-516 |
MS35338-45 |
MS35338-140 |
.583 |
.078 |
3/8” |
AN935-616 |
MS35338-46 |
MS35338-141 |
.680 |
.094 |
7/16” |
AN935-716 |
MS35338-47 |
MS35338-142 |
.776 |
.109 |
1/2" |
AN935-816 |
MS35338-48 |
MS35338-143 |
.869 |
.125 |
AN960 Flat washers
The an960 flat washer is available in Stainless, steel, and Aluminum and typically 2-3 thicknesses. The AN960 spec was replaced in 2011 by the NAS1149 specification.
Material:
‘-‘ Carbon steel cad plated
‘C’ Stainless steel
‘D’ Aluminum
The aluminum washers are available in several finishes:
‘J’ – Chemical conversion coating (alodine) and is rarely used
‘K’ – Anodized (most common in aviation at this time)
‘P’ – older form of anodize (designation canceled in 1982 see note below)
‘D’ – Untreated, used mainly for ground studs.
Size: for screw sizes 3-11, use the screw size
For bolts ¼” or larger use the diameter in 1/16” increments and add 16 to the end
Thicknesses:
‘LL’ – Very thin
‘L’ – Thin
No code, standard thickness
The PD finish was superseded by the KD code in 1982, however Aircraft Spruce and others still actively use the PD code. Most likely the washers you receive will technically be KD. Since PD is so prevalent, we will continue to use the PD coding.
Normal Usage: It is typically recommended to use a washer with the same material it is against. This allows the washer to act as a sacrificial item to reduce chance of corrosion on the actual part. But if the bolt is in tension, it is usually recommended to use the steel or stainless steel.
Typically you want to have at least one under the nut, but usually no more than 2.
For structures where damage can easily occur, use a thin one under the head.
AN960 continued
Bolt or screw size |
Hole dia. |
Outside diameter |
Thickness |
Steel |
Stainless |
Aluminum KD finish |
Aluminum PD finish |
Aluminum No finish |
4 |
.125 |
.312 |
.016 .032 |
-4L -4 |
-C4L -C4 |
-KD4L -KD4 |
-PD4L -PD4 |
-D4L -D4 |
6 |
.140 |
.375 |
.016 .032 |
-6L -6 |
-C6L -C6 |
-KD6L -KD6 |
-PD6L -PD6 |
-D6L -D6 |
8 |
.174 |
.375 |
.016 .032 |
-8L -8 |
-C8L -C8 |
-KD8L -KD8 |
-PD8L -PD8 |
-D8L -D8 |
10 |
.203 |
.438 |
.016 .032 .063 |
-10L -10 |
-C10L -C10 |
-KD10LL -KD10L -KD10 |
-PD10LL -PD10L -PD10 |
-D10L
-D10 |
¼” |
.265 |
.500 |
.016 .032 .063 |
-416L -416 |
-C416L -C416 |
-KD416L
-KD416 |
-PD416L
-PD416 |
-D416L
-D416 |
5/16” |
.328 |
.562 |
.016 .032 .063 |
-516L -516 |
-C516L -C516 |
-KD516L
-KD516 |
-PD516L
-PD516 |
-D516L
-D516 |
3/8” |
.390 |
.625 |
.016 .032 .063 |
-616LL -616L -616 |
-C616LL -C616L -C616 |
-KD616L
-KD616 |
-PD616L
-PD616 |
-D616L
-D616 |
7/16” |
.453 |
.750 |
.016 .032 .063 |
-716L -716 |
-C716L -C716 |
-KD716L
-KD716 |
-PD716L
-PD716 |
-D716L
-D716 |
½” |
.515 |
.875 |
.016 .032 .063 |
-816L -816 |
-C816L -C816 |
-KD816L
-KD816 |
-PD816L
-PD816 |
-D816L
-D816 |
9/16” |
.578 |
1.062 |
.016 .032 .063 |
-916L -916 |
-C916L -C916 |
-KD916L
-KD916 |
-PD916L
-PD916 |
-D916L
-D916 |
5/8” |
.640 |
1.188 |
.016 .032 .063 |
-1016L -1016 |
-C1016L -C1016 |
-KD1016L
-KD1016 |
-PD1016L
-PD1016 |
-D1016L
-D1016 |
¾” |
.765 |
1.312 |
.016 .032 .063 |
-1216L -1216 |
-C1216L -C1216 |
-KD1216L
-KD1216 |
-PD1216L
-PD1216 |
-D1216L
-D1216 |
AN970 Flat Washer, oversized Steel Cad plated
Typically used where a large bearing surface is required, on flight controls to retain rod end bearings, in areas where larger size makes it easier to install multiple washers.
Dash number is for size of screw/bolt in 1/16” increments
Current spec: NASM 970 (still uses AN970 for part number)
Dash Number |
Bolt Size |
Hole diameter |
Outside Diameter |
Thickness |
-3 |
#10 (3/16”) |
.203 |
.875 |
.063 |
-4 |
¼ |
.265 |
1.125 |
.063 |
-5 |
5/16 |
.328 |
1.375 |
.063 |
-6 |
3/8 |
.390 |
1.625 |
.063 |
-7 |
7/16 |
.453 |
1.812 |
.109 |
-8 |
½ |
.515 |
2.000 |
.109 |
-9 |
9/16 |
.578 |
2.188 |
.125 |
-10 |
5/8 |
.640 |
2.375 |
.125 |
MS51412 Flat Washer (diameter is between AN960 and AN970)
Typically used where heavy washer is required and as a reduced diameter safety washer in place of the AN970.
Material: Steel washers are Grades 1008 through 1020 Alloy steel is Grade 4130
Specification cancelled, no known replacement.
Dash Numbers |
Inside diameter |
Outside Diameter |
Thickness (Nominal) |
Thickness Range |
||
Carbon steel |
Alloy steel |
Min. |
Max. |
|||
20 |
20A |
.156 |
.281 |
.020 |
.016 |
.025 |
1 |
1A |
.156 |
.375 |
.049 |
.036 |
.065 |
18 |
18A |
.188 |
.438 |
.049 |
.036 |
.065 |
2 |
2A |
.219 |
.500 |
.049 |
.036 |
.065 |
3 |
3A |
.250 |
.562 |
.049 |
.036 |
.065 |
21 |
21A |
.219 |
.656 |
.062 |
.055 |
.069 |
22 |
22A |
.234 |
.375 |
.049 |
.043 |
.051 |
23 |
23A |
.266 |
.812 |
.109 |
.075 |
.119 |
24 |
24A |
.266 |
1.000 |
.064 |
.059 |
.069 |
4 |
4A |
.281 |
.625 |
.065 |
.043 |
.051 |
36 |
36A |
.281 |
.968 |
.049 |
.046 |
.119 |
37 |
37A |
.281 |
2.000 |
.062 |
.051 |
.080 |
5 |
5A |
.312 |
.734 |
.065 |
.051 |
.080 |
25 |
25A |
.344 |
1.000 |
.062 |
.059 |
.067 |
NAS1149 Flat washers
Material:
‘A’ Aluminum 2024-T81
‘B’ Brass
‘F‘ Carbon steel cad plated
‘C’ Stainless steel
‘D’ Aluminum 2024-T3
‘G’ Alloy steel
The aluminum washers are available in several finishes:
‘H’ – Untreated
‘J’ – Chemical Treat
‘K’ – Anodized (most common in aviation at this time)
‘P’- Cadmium Plated
‘R’- Passivated
Size: for screw sizes 3-11, use the ‘N’ + screw size
For bolts ¼” or larger use the diameter in 1/16” increments and add 16 to the end
Thicknesses:
Use the thickness in decimal
Normal Usage: It is typically recommended to use a washer with the same material it is against. This allows the washer to act as a sacrificial item to reduce chance of corrosion on the actual part. But if the bolt is in tension, it is usually recommended to use the steel or stainless steel.
Typically you want to have at least one under the nut, but usually no more than 2.
For structures where damage can easily occur, use a thin one under the head.
Part number consists of
NAS1149 + material code + Size and thickness code + finish code
Example: NAS1149DN832K is an aluminum #8 washer, .032” thick, anodized
NAS1149F0332P is a Steel, 3/16 washer, .032” thick, Cad plated
NAS1149 continued
Bolt or screw size |
Hole dia. |
Outside diameter |
Thickness |
Steel |
Stainless |
Aluminum K finish |
Aluminum No finish |
4 |
.125 |
.312 |
.016 .032 |
FN416P FN432P |
CN416R CN432R |
DN416K DN432K |
DN416H DN432H |
6 |
.140 |
.375 |
.016 .032 |
FN616P FN632P |
CN616R CN632R |
DN616K DN632K |
DN616H DN632H |
8 |
.174 |
.375 |
.016 .032 |
FN816P FN832P |
CN816R CN832R |
DN816K DN832K |
DN816H DN832H |
10 |
.203 |
.438 |
.016 .032 .063 |
F0316P F0332P F0363P |
C0316R C0332R C0363R |
D0316K D0332K D0363K |
D0316H D0332H D0363H |
¼” |
.265 |
.500 |
.016 .032 .063 |
F0416P F0432P F0463P |
C0416R C0432R C0463R |
D0416K D0432K D0463K |
D0416H D0432H D0463H |
5/16” |
.328 |
.562 |
.016 .032 .063 |
F0516P F0532P F0563P |
C0516R C0532R C0563R |
D0516K D0532K D0563K |
D0516H D0532H D0563H |
3/8” |
.390 |
.625 |
.016 .032 .063 |
F0616P F0632P F0663P |
C0616R C0632R C0663R |
D0616K D0632K D0663K |
D0616H D0632H D0663H |
7/16” |
.453 |
.750 |
.016 .032 .063 |
F0716P F0732P F0763P |
C0716R C0732R C0763R |
D0716K D0732K D0763K |
D0716H D0732H D0763H |
½” |
.515 |
.875 |
.016 .032 .063 |
F0816P F0832P F0863P |
C0816R C0832R C0863R |
D0816K D0832K D0863K |
D0816H D0832H D0863H |
9/16” |
.578 |
1.062 |
.016 .032 .063 |
F0916P F0932P F0963P |
C0916R C0932R C0963R |
D0916K D0932K D0963K |
D0916H D0932H D0963H |
5/8” |
.640 |
1.188 |
.016 .032 .063 |
F1016P F1032P F1063P |
C1016R C1032R C1063R |
D1016K D1032K D1063K |
D1016H D1032H D1063H |
¾” |
.765 |
1.312 |
.016 .032 .090 |
F1216P F1232P F1290P |
C1216R C1232R C1290R |
D1216K D1232K D1290K |
D1216H D1232H D1290H |
AN960 to NAS1149 cross reference table
PART NUMBERS |
|||
Steel Washers |
Stainless Steel Washers |
||
AN960 PART NUMBER |
NAS1149 PART NUMBER |
AN960 PART NUMBER |
NAS1149 PART NUMBER |
AN960-4L |
NAS1149FN416P |
AN960C4L |
NAS1149CN416R |
AN960-4 |
NAS1149FN432P |
AN960C4 |
NAS1149CN432R |
AN960-5 |
NAS1149FN542P |
AN960C5 |
NAS1149CN542R |
AN960-6L |
NAS1149FN616P |
AN960C6L |
NAS1149CN616R |
AN960-6 |
NAS1149FN632P |
AN960C6 |
NAS1149CN632R |
AN960-8L |
NAS1149FN816P |
AN960C8L |
NAS1149CN816R |
AN960-8 |
NAS1149FN832P |
AN960C8 |
NAS1149CN832R |
AN960-9 |
NAS1149FN949P |
AN960C9 |
NAS1149CN949R |
AN960-10L |
NAS1149F0332P |
AN960C10L |
NAS1149C0332R |
AN960-10 |
NAS1149F0363P |
AN960C10 |
NAS1149C0363R |
AN960-11 |
NAS1149F1165P |
AN960C11 |
NAS1149C1165R |
AN960-416L |
NAS1149F0432P |
AN960C416L |
NAS1149C0432R |
AN960-416 |
NAS1149F0463P |
AN960C416 |
NAS1149C0463R |
AN960-516L |
NAS1149F0532P |
AN960C516L |
NAS1149C0532R |
AN960-516 |
NAS1149F0563P |
AN960C516 |
NAS1149C0563R |
AN960-616LL |
NAS1149F0616P |
AN960C616LL |
NAS1149C0616R |
AN960-616L |
NAS1149F0632P |
AN960C616L |
NAS1149C0632R |
AN960-616 |
NAS1149F0663P |
AN960C616 |
NAS1149C0663R |
AN960-716L |
NAS1149F0732P |
AN960C716L |
NAS1149C0732R |
AN960-716 |
NAS1149F0763P |
AN960C716 |
NAS1149C0763R |
AN960-816L |
NAS1149F0832P |
AN960C816L |
NAS1149C0832R |
AN960-816 |
NAS1149F0863P |
AN960C816 |
NAS1149C0863R |
AN960-916L |
NAS1149F0932P |
AN960C916L |
NAS1149C0932R |
AN960-916 |
NAS1149F0963P |
AN960C916 |
NAS1149C0963R |
AN960-1016L |
NAS1149F1032P |
AN960C1016L |
NAS1149C1032R |
AN960-1016 |
NAS1149F1063P |
AN960C1016 |
NAS1149C1063R |
AN960-1216L |
NAS1149F1232P |
AN960C1216L |
NAS1149C1232R |
AN960-1216 |
NAS1149F1290P |
AN960C1216 |
NAS1149C1290R |
AN960 to NAS1149 cross reference table (continued)
PART NUMBERS |
|||
Aluminum Washer K finish |
Aluminum Washer P finish |
||
AN960 PART NUMBER |
NAS1149 PART NUMBER |
AN960 PART NUMBER |
NAS1149 PART NUMBER |
AN960KD4L |
NAS1149DN416K |
AN960PD4L |
NAS1149DN416J |
AN960KD4 |
NAS1149DN432K |
AN960PD4 |
NAS1149DN432J |
AN960KD5 |
NAS1149DN542K |
AN960PD5 |
NAS1149DN542J |
AN960KD6L |
NAS1149DN616K |
AN960PD6L |
NAS1149DN616J |
AN960KD6 |
NAS1149DN632K |
AN960PD6 |
NAS1149DN632J |
AN960KD8L |
NAS1149DN816K |
AN960PD8L |
NAS1149DN816J |
AN960KD8 |
NAS1149DN832K |
AN960PD8 |
NAS1149DN832J |
AN960KD9 |
NAS1149DN949K |
AN960PD9 |
NAS1149DN949J |
AN960KD10LL |
NAS1149D0316K |
AN960PD10L |
NAS1149D0316J |
AN960KD10L |
NAS1149D0332K |
AN960PD10 |
NAS1149D0363J |
AN960KD10 |
NAS1149D0363K |
AN960PD11 |
NAS1149D1165J |
AN960KD11 |
NAS1149D1165K |
AN960PD416L |
NAS1149D0416J |
AN960KD416L |
NAS1149D0416K |
AN960PD416 |
NAS1149D0463J |
AN960KD416 |
NAS1149D0463K |
AN960PD516L |
NAS1149D0516J |
AN960KD516L |
NAS1149D0516K |
AN960PD516 |
NAS1149D0563J |
AN960KD516 |
NAS1149D0563K |
AN960PD616L |
NAS1149D0616J |
AN960KD616L |
NAS1149D0616K |
AN960PD616 |
NAS1149D0663J |
AN960KD616 |
NAS1149D0663K |
AN960PD716L |
NAS1149D0716J |
AN960KD716L |
NAS1149D0716K |
AN960PD716 |
NAS1149D0763J |
AN960KD716 |
NAS1149D0763K |
AN960PD816L |
NAS1149D0816J |
AN960KD816L |
NAS1149D0816K |
AN960PD816 |
NAS1149D0863J |
AN960KD816 |
NAS1149D0863K |
AN960PD916L |
NAS1149D0916J |
AN960KD916L |
NAS1149D0916K |
AN960PD916 |
NAS1149D0963J |
AN960KD916 |
NAS1149D0963K |
AN960PD1016L |
NAS1149D1016J |
AN960KD1016L |
NAS1149D1016K |
AN960PD1016 |
NAS1149D1063J |
AN960KD1016 |
NAS1149D1063K |
AN960PD1216L |
NAS1149D1216J |
AN960KD1216L |
NAS1149D1216K |
AN960PD1216 |
NAS1149D1290J |
AN960KD1216 |
NAS1149D1290K |
AN960PD4L |
NAS1149DN416J |
AN960 to NAS1149 cross reference table (continued)
Aluminum Washer D finish (no finish) |
|
AN960 PART NUMBER |
NAS1149 PART NUMBER |
AN960D4L |
NAS1149DN416H |
AN960D4 |
NAS1149DN432H |
AN960D5 |
NAS1149DN542H |
AN960D6L |
NAS1149DN616H |
AN960D6 |
NAS1149DN632H |
AN960D8L |
NAS1149DN816H |
AN960D8 |
NAS1149DN832H |
AN960D9 |
NAS1149DN949H |
AN960D10L |
NAS1149D0316H |
AN960D10 |
NAS1149D0363H |
AN960D11 |
NAS1149D1165H |
AN960D416L |
NAS1149D0416H |
AN960D416 |
NAS1149D0463H |
AN960D516L |
NAS1149D0516H |
AN960D516 |
NAS1149D0563H |
AN960D616L |
NAS1149D0616H |
AN960D616 |
NAS1149D0663H |
AN960D716L |
NAS1149D0716H |
AN960D716 |
NAS1149D0763H |
AN960D816L |
NAS1149D0816H |
AN960D816 |
NAS1149D0863H |
AN960D916L |
NAS1149D0916H |
AN960D916 |
NAS1149D0963H |
AN960D1016L |
NAS1149D1016H |
AN960D1016 |
NAS1149D1063H |
AN960D1216L |
NAS1149D1216H |
AN960D1216 |
NAS1149D1290H |
AN960D4L |
NAS1149DN416H |
NAS1169 Finishing washer 100 degree countersink (dimpled)
These washers are used mainly in fiberglass or thin material with countersunk screws. Requires oversized hole/countersunk hole in material.
Available in cad plated steel or stainless steel
Aircraft Spruce uses their own numbers which are a commercial equivelant
Current spec: NAS1169
Common sizes
Bolt size |
OD |
Height |
Thickness |
Steel |
Stainless Steel |
Aircraft Spruce (stainless) |
6 (.138) |
.475 |
.076 .082 |
.016 .025 |
-6L -6 |
-C6L -C6 |
04-00397 |
8 (.164) |
.562 |
.087 .094 |
.016 .025 |
-8L -8 |
-C8L -C8 |
04-00392 |
10 (.190) |
.625 |
.099 .101 |
.016 .025 |
-10L -10 |
-C10L -C10 |
04-00398 |
1/4 |
.750 |
.125 .132 |
.016 .025 |
-416L -416 |
-C416L -C416 |
|
