MS51923 Coiled Spring Pin Decoder: Dash Number Lookup

What Size Is MS51923-37?

MS51923-37 is a 1/16 in coiled spring pin, 3/16 in long, in cadmium-plated carbon steel. That is the sheet's own example. MS51923 numbers carry no code: the dash number is a lookup into the standard's tables. Each number fixes the diameter, the length, the material and the finish. NASM51923 numbers are identical.

Type a part number to get its free diameter, recommended hole, length tolerance, double-shear strength, material and finish. Going the other way? Type a size, such as 1/8 x 1/2, to get every part number for it.

MS51923 DECODER

coiled spring pins · standard duty MS51923 Rev C, May 1969

Part number or size

Examples:

Part number	Dia	Free Ø in	Length	L in	Material	Shear lb

How an MS51923 Part Number Works

MS51923 the standard (Note 7) 37 the dash number: a lookup in Table II that sets diameter, length, material and finish

Rev C uses every dash number from 1 to 604 once. 498 are current (Table II). 106 are superseded or inactive (Tables III and IV). There is no repeating offset between materials, so look each number up.

Current Dash Numbers (Table II)

Nominal Ø, in	Length L, in	Carbon steel, cadmium	Carbon steel, phosphate	CRES 302	CRES 410–420	Alloy 6150, phosphate
1/32	1/8			111	166
	3/16			112	167
	1/4			113	168
	5/16			114	169
	3/8			115	170
	7/16			116	171
	1/2			117	172
	9/16			118	173
	5/8			119	174
.039	1/8			120	175
	3/16			121	176
	1/4			122	177
	5/16			123	178
	3/8			124	179
	7/16			125	180
	1/2			126	181
	9/16			127	182
	5/8			128	183
3/64	1/8			129	184
	3/16			130	185
	1/4			131	186
	5/16			132	187
	3/8			133	188
	7/16			134	189
	1/2			135	190
	9/16			136	191
	5/8			137	192
.052	1/8			138	193
	3/16			139	194
	1/4			140	195
	5/16			141	196
	3/8			142	197
	7/16			143	198
	1/2			144	199
	9/16			145	200
	5/8			146	201
1/16	3/16	37	92	147	424
	1/4	38	93	148	425
	5/16	39	94	149	426
	3/8	40	95	150	427
	7/16	41	96	151	428
	1/2	42	97	152	429
	9/16	43	98	153	430
	5/8	44	99	154	431
	11/16	45	100	155	432
	3/4	46	101	156	433
5/64	1/4	228	270	312	434
	5/16	229	271	313	435
	3/8	230	272	314	436
	7/16	231	273	315	437
	1/2	232	274	316	438
	9/16	233	275	317	439
	5/8	234	276	318	440
	3/4	235	277	319	441
	7/8	585	590	595	600
3/32	1/4	47	102	157	442
	5/16	48	103	158	443
	3/8	49	104	159	444
	7/16	50	105	160	445
	1/2	51	106	161	446
	9/16	52	107	162	447
	5/8	53	108	163	448
	3/4	54	109	164	449
	7/8	55	110	165	450
	1	421	422	423	451
7/64	3/8	236	278	320	452
	7/16	237	279	321	453
	1/2	238	280	322	454
	9/16	239	281	323	455
	5/8	240	282	324	456
	3/4	241	283	325	457
	7/8	242	284	326	458
	15/16	243	285	327	459
	1	586	591	596	601
	1-1/4	587	592	597	602
	1-1/2	588	593	598	603
1/8	3/8	202	244	286	460
	7/16	203	245	287	461
	1/2	204	246	288	462
	9/16	205	247	289	463
	5/8	206	248	290	464
	3/4	207	249	291	465
	7/8	208	250	292	466
	15/16	209	251	293	467
	1	589	594	599	604
5/32	7/16	328	358	388	468
	1/2	329	359	389	469
	9/16	330	360	390	470
	5/8	331	361	391	471
	3/4	332	362	392	472
	7/8	333	363	393	473
	15/16	334	364	394	474
3/16	1/2	210	252	294	475
	9/16	211	253	295	476
	5/8	212	254	296	477
	3/4	213	255	297	478
	7/8	214	256	298	479
	1	215	257	299	480
7/32	1/2	335	365	395	481
	9/16	336	366	396	482
	5/8	337	367	397	483
	3/4	338	368	398	484
	7/8	339	369	399	485
	1	340	370	400	486
	1-1/4	418	419	420	487
1/4	1/2	216	258	300	488
	9/16	217	259	301	489
	5/8	218	260	302	490
	3/4	219	261	303	491
	7/8	220	262	304	492
	1	221	263	305	493
	1-1/8	222	264	306	494
5/16	3/4	341	371	401	495
	13/16	342	372	402	496
	7/8	343	373	403	497
	15/16	344	374	404	498
	1	345	375	405	499
	1-1/8	346	376	406	500
	1-1/4	347	377	407	501
3/8	3/4	223	265	307	502
	1	224	266	308	503
	1-1/4	225	267	309	504
	1-3/4	226	268	310	505
	2	227	269	311	506
7/16	1	348	378	408	507
	1-1/4	349	379	409	508
	1-1/2	350	380	410	509
	1-3/4	351	381	411	510
	2	352	382	412	511
1/2	1-1/4	353	383	413	512
	1-1/2	354	384	414	513
	1-3/4	355	385	415	514
	2	356	386	416	515
	2-1/4	357	387	417	516
5/8	2					534
	2-1/4					535
	2-1/2					536
	2-3/4					537
	3					538
	3-1/4					539
	3-1/2					540
	3-3/4					541
	4					542
	4-1/4					543
	4-1/2					544
	4-3/4					545
	5					546
	5-1/4					547
	5-1/2					548
	5-3/4					549
	6					550
3/4	2					568
	2-1/4					569
	2-1/2					570
	2-3/4					571
	3					572
	3-1/4					573
	3-1/2					574
	3-3/4					575
	4					576
	4-1/4					577
	4-1/2					578
	4-3/4					579
	5					580
	5-1/4					581
	5-1/2					582
	5-3/4					583
	6					584

Carbon steel is 1070 thru 1095. A blank cell means the size is not made in that material. Confirm the 1/4 × 1-1/8 in row against the drawing.

Superseded Dash Numbers and Replacements (Tables III and IV)

Nominal Ø, in	Length L, in	Superseded dash numbers	Recommended replacements
1/32	1/8	1, 56	111, 166
	3/16	2, 57	112, 167
	1/4	3, 58	113, 168
	5/16	4, 59	114, 169
	3/8	5, 60	115, 170
	7/16	6, 61	116, 171
	1/2	7, 62	117, 172
	9/16	8, 63	118, 173
	5/8	9, 64	119, 174
.039	1/8	10, 65	120, 175
	3/16	11, 66	121, 176
	1/4	12, 67	122, 177
	5/16	13, 68	123, 178
	3/8	14, 69	124, 179
	7/16	15, 70	125, 180
	1/2	16, 71	126, 181
	9/16	17, 72	127, 182
	5/8	18, 73	128, 183
3/64	1/8	19, 74	129, 184
	3/16	20, 75	130, 185
	1/4	21, 76	131, 186
	5/16	22, 77	132, 187
	3/8	23, 78	133, 188
	7/16	24, 79	134, 189
	1/2	25, 80	135, 190
	9/16	26, 81	136, 191
	5/8	27, 82	137, 192
.052	1/8	28, 83	138, 193
	3/16	29, 84	139, 194
	1/4	30, 85	140, 195
	5/16	31, 86	141, 196
	3/8	32, 87	142, 197
	7/16	33, 88	143, 198
	1/2	34, 89	144, 199
	9/16	35, 90	145, 200
	5/8	36, 91	146, 201
5/8	2	517	534
	2-1/4	518	535
	2-1/2	519	536
	2-3/4	520	537
	3	521	538
	3-1/4	522	539
	3-1/2	523	540
	3-3/4	524	541
	4	525	542
	4-1/4	526	543
	4-1/2	527	544
	4-3/4	528	545
	5	529	546
	5-1/4	530	547
	5-1/2	531	548
	5-3/4	532	549
	6	533	550
3/4	2	551	568
	2-1/4	552	569
	2-1/2	553	570
	2-3/4	554	571
	3	555	572
	3-1/4	556	573
	3-1/2	557	574
	3-3/4	558	575
	4	559	576
	4-1/4	560	577
	4-1/2	561	578
	4-3/4	562	579
	5	563	580
	5-1/4	564	581
	5-1/2	565	582
	5-3/4	566	583
	6	567	584

1/32 to .052 in: carbon steel cadmium (1–36) and phosphate (56–91) are not manufactured. The replacements are the same size in CRES 302 and CRES 410–420. 5/8 and 3/4 in: alloy 6150 cadmium (517–533, 551–567) is inactivated. The replacement is the same size in phosphate-coated 6150.

Free Diameter, Chamfer, Shear Strength and Hole Size (Table I)

Nominal size, in	Free Ø D, in	Chamfer Ø B max, in	Double shear, carbon steel & CRES 410–420, lb min	Double shear, alloy 6150, lb min	Double shear, CRES 302, lb min	Recommended hole, in
1/32 (0.031)	0.033–0.035	0.029	75^*	–	60	0.031–0.032
.039	0.041–0.044	0.037	120^*	–	100	0.039–0.040
3/64 (0.047)	0.049–0.052	0.045	170^*	–	140	0.046–0.048
.052	0.054–0.057	0.050	230^*	–	190	0.051–0.053
1/16 (0.062)	0.067–0.072	0.059	300	–	250	0.061–0.065
5/64 (0.078)	0.083–0.088	0.075	475	–	400	0.077–0.081
3/32 (0.094)	0.099–0.105	0.091	700	–	550	0.093–0.097
7/64 (0.109)	0.114–0.120	0.106	950	–	750	0.108–0.112
1/8 (0.125)	0.131–0.138	0.121	1,250	–	1,000	0.124–0.129
5/32 (0.156)	0.163–0.171	0.152	1,925	–	1,550	0.155–0.160
3/16 (0.188)	0.196–0.205	0.182	2,800	–	2,250	0.185–0.192
7/32 (0.219)	0.228–0.238	0.214	3,800	–	3,000	0.217–0.224
1/4 (0.250)	0.260–0.271	0.243	5,000	–	4,000	0.247–0.256
5/16 (0.312)	0.324–0.337	0.304	7,700	–	6,200	0.308–0.319
3/8 (0.375)	0.388–0.403	0.366	11,200	–	9,000	0.370–0.383
7/16 (0.438)	0.452–0.469	0.427	15,200	–	13,000	0.431–0.446
1/2 (0.500)	0.516–0.535	0.488	20,000	–	16,000	0.493–0.510
5/8 (0.625)	0.642–0.661	0.613	–	31,000	–	0.618–0.635
3/4 (0.750)	0.768–0.787	0.738	–	45,000	–	0.743–0.760

^* CRES 410 thru 420 only. Free Ø is the diameter before installation. 1 lb = 4.448 N; 1 in = 25.4 mm.

Reference Guide: MS51923 Coiled Spring Pins

Reading the Number

Note 7: the part number is the MS number plus the dash number. The sheet's example is MS51923-37. Nothing is coded in the digits. The number's place in Table II sets the diameter, the length, the material and the finish.

MS51923-37: 1/16 × 3/16 in, carbon steel, cadmium plated.
MS51923-204: 1/8 × 1/2 in, carbon steel, cadmium plated.
MS51923-462: 1/8 × 1/2 in, CRES 410 thru 420.

No offset pattern

Unlike MS16555, the materials are not a fixed number apart. Each column was numbered in blocks. Lengths added later took the next free numbers (418–423 and 585–604). So 1/8 × 1/2 in is 204, 246, 288 and 462. Always look the number up.

Lengths run 1/8 to 2-1/4 in for 1/32 to 1/2 in pins, and 2 to 6 in for 5/8 and 3/4 in. Small sizes (1/32 to .052 in) are current in CRES only. Large sizes (5/8 and 3/4 in) are current in alloy 6150 only.

Material, Hardness, Finish and Tolerances

Material (Note 1)	Hardness (Note 3)	Finish (Note 2)
Carbon steel 1070–1095	HRC 46–53	Cadmium per QQ-P-416, Type II, Class 3, or phosphate per MIL-P-16232, Type Z, Class 2
Alloy steel 6150	HRC 43–51	Phosphate per MIL-P-16232, Type Z, Class 2
CRES 410 thru 420	HRC 46–55	Passivated per QQ-P-35
CRES 302	Work hardened	Passivated per QQ-P-35

Steels are per Federal Standard No. 66. All sharp edges are broken (Note 4). The finish specs are the 1969 ones; most have since been replaced.

Length tolerance (Note 6)

Diameter	Length	Tolerance
3/8 in and under	thru 2 in	±.010 in (±0.25 mm)
	over 2 thru 3 in	±.015 in (±0.38 mm)
	over 3 in	±.025 in (±0.64 mm)
over 3/8 in	all lengths	±.025 in (±0.64 mm)

CRES 302 is about 20% weaker in double shear than carbon steel or CRES 410–420 of the same size (Table I). For limits on how spring pins may be used, the sheet points to MS33547 (Note 10).

Status, NASM51923 and Coiled vs Slotted Pins

MS51923 Revision C is dated 23 May 1969 (first approved 3 March 1962). Notice 1 (15 March 1996) found it valid for use in acquisition. The cancellation notice of 1 October 1998 cancelled it and named NASM51923 as the replacement. It states that the part numbers are identical, so MS51923-37 and NASM51923-37 are the same pin.

Superseded numbers (Tables III and IV) are not for new design. Table IV lists the recommended replacement for each one.

Coiled (MS51923) vs slotted (MS16562)

The MS51923 sheet describes a tubular pin rolled in a coil, with a swaged chamfer at the end. Its free diameter is larger than the recommended hole, so the pin compresses when driven in. The sheet title calls it "standard duty". It says nothing about slotted pins; MS16562 is a separate standard, and this page does not compare their strengths.

Source: MS51923C sheets 1 to 4, Notice 1 and the cancellation notice, from the DLA ASSIST database (Distribution A).

MS51923 / NASM51923 Coiled Spring Pin Part Number Decoder: Diameter, Length, Material, Hole Size and Shear Strength

Reading the Number

Material, Hardness, Finish and Tolerances

Status, NASM51923 and Coiled vs Slotted Pins

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