MS24694 at a glance

MS24694, screw, machine, flat countersunk head, 100 degree, structural, cross recessed, unc-3a and unf-3a — MS24694

MS24694 engineering drawing with dimensions — MS24694

Specification

Item	Value
Head	flat countersunk, 100 degree, structural
Drive	cross-recess (MS9006)
Thread series	UNC-3A (#8) and UNF-3A (other sizes)
Material	Low-alloy steel, Rockwell C26 to C32, MIL-S-6049 or MIL-S-6050. Aluminum alloy 2024, QQ-A-430 or QQ-A-225 (T4). Corrosion resisting steel, FED-STD-66 steel no. 302, 303, 304, 305 or 316 or equal/interchangeable with 16-18 or 18-8 chromium nickel alloy steel (developed for cold heading).
Heat treatment	Low-alloy steel 125,000 to 145,000 psi tensile strength, MIL-H-6875. QQ-A-430 aluminum alloy 62,000 psi minimum, MIL-H-6088.

Item	Value
Finish	Low-alloy steel: cadmium plate QQ-P-416 Type II Class 3. Aluminum alloy: anodize MIL-A-8625 Type I or II. CRES: passivate QQ-P-35.
Procurement	MIL-S-7839
Thread specification	MIL-S-7742
Status	Rev. C (17 Feb 1969) with Amendment 1 (14 Apr 1992). Notice 1 (27 Oct 1999): canceled and superseded by NASM24694; the part numbers are identical (MS24694-S1 = NASM24694-S1). Supersedes AN509.

Dimensions by size

Dimension, in	.164-32 UNC-3A	.190-32 UNF-3A	.250-28 UNF-3A	.3125-24 UNF-3A	.375-24 UNF-3A	.4375-20 UNF-3A	.500-20 UNF-3A	.5625-18 UNF-3A
nominal	#8	#10	1/4	5/16	3/8	7/16	1/2	9/16
D screw dia	.161 – .164	.186 – .189	.246 – .249	.3085 – .3115	.371 – .374	.4325 – .4365	.495 – .499	.5575 – .5615
A head dia	max sharp .332, min sharp .319, abs min .283	max sharp .385, min sharp .371, abs min .327	max sharp .507, min sharp .491, abs min .447	max sharp .635, min sharp .617, abs min .569	max sharp .762, min sharp .742, abs min —	max sharp .890, min sharp .868, abs min .805	max sharp 1.017, min sharp .992, abs min .919	max sharp 1.145, min sharp 1.118, abs min 1.036
F flat max	.015	.016	.018	.020	—	.026	.030	.034
H head height ref	.068	.080	.106	.133	.159	.186	.213	.240
M point max	.031	.031	.031	.047	.047	.047	.047	.047
R fillet	.005 – .015	.005 – .015	.005 – .015	.010 – .020	.010 – .020	.010 – .020	.010 – .020	.010 – .020
min tensile lbf	low alloy steel 1750, aluminum alloy 870, corrosion resistant steel 1190	low alloy steel 2500, aluminum alloy 1240, corrosion resistant steel 1700	low alloy steel 4550, aluminum alloy 2250, corrosion resistant steel 3090	low alloy steel 7250, aluminum alloy 3600, corrosion resistant steel 4930	low alloy steel 10980, aluminum alloy 5440, corrosion resistant steel 7460	low alloy steel 14840, aluminum alloy 7360, corrosion resistant steel 10090	low alloy steel 19990, aluminum alloy 9910, corrosion resistant steel 13590	low alloy steel 25380, aluminum alloy 12590, corrosion resistant steel 17260

Minimum – maximum as tabulated in MS24694 Rev. C; letters as on the standard's drawing.

Part numbers and lengths

Every part number of MS24694 Rev. C, by thread size, each with its own link. * = the material code: build the full number below.

.164-32 UNC-3A35 part numbers

Part no.	Length, in
MS24694-*1	9/32
MS24694-*2	11/32
MS24694-*3	13/32
MS24694-*4	15/32
MS24694-*5	17/32
MS24694-*6	19/32
MS24694-*7	21/32
MS24694-*8	23/32
MS24694-*9	25/32
MS24694-*10	27/32
MS24694-*11	29/32
MS24694-*12	31/32
MS24694-*13	1-1/32
MS24694-*14	1-3/32
MS24694-*15	1-5/32
MS24694-*16	1-7/32
MS24694-*17	1-9/32
MS24694-*18	1-11/32
MS24694-*19	1-13/32
MS24694-*20	1-15/32
MS24694-*21	1-17/32
MS24694-*22	1-19/32
MS24694-*23	1-21/32
MS24694-*24	1-23/32
MS24694-*25	1-25/32
MS24694-*26	1-27/32
MS24694-*27	1-29/32
MS24694-*28	1-31/32
MS24694-*29	2-1/32
MS24694-*30	2-3/32
MS24694-*31	2-5/32
MS24694-*32	2-7/32
MS24694-*33	2-9/32
MS24694-*34	2-11/32
MS24694-*35	2-13/32

.190-32 UNF-3A45 part numbers

Part no.	Length, in
MS24694-*46	9/32
MS24694-*47	11/32
MS24694-*48	13/32
MS24694-*49	15/32
MS24694-*50	17/32
MS24694-*51	19/32
MS24694-*52	21/32
MS24694-*53	23/32
MS24694-*54	25/32
MS24694-*55	27/32
MS24694-*56	29/32
MS24694-*57	31/32
MS24694-*58	1-1/32
MS24694-*59	1-3/32
MS24694-*60	1-5/32
MS24694-*61	1-7/32
MS24694-*62	1-9/32
MS24694-*63	1-11/32
MS24694-*64	1-13/32
MS24694-*65	1-15/32
MS24694-*66	1-17/32
MS24694-*67	1-19/32
MS24694-*68	1-21/32
MS24694-*69	1-23/32
MS24694-*70	1-25/32
MS24694-*71	1-27/32
MS24694-*72	1-29/32
MS24694-*73	1-31/32
MS24694-*74	2-1/32
MS24694-*75	2-3/32
MS24694-*76	2-5/32
MS24694-*77	2-7/32
MS24694-*78	2-9/32
MS24694-*79	2-11/32
MS24694-*80	2-13/32
MS24694-*81	2-15/32
MS24694-*82	2-17/32
MS24694-*83	2-19/32
MS24694-*84	2-21/32
MS24694-*85	2-23/32
MS24694-*86	2-25/32
MS24694-*87	2-27/32
MS24694-*88	2-29/32
MS24694-*89	2-31/32
MS24694-*90	3-1/32

.250-28 UNF-3A44 part numbers

Part no.	Length, in
MS24694-*92	11/32
MS24694-*93	13/32
MS24694-*94	15/32
MS24694-*95	17/32
MS24694-*96	19/32
MS24694-*97	21/32
MS24694-*98	23/32
MS24694-*99	25/32
MS24694-*100	27/32
MS24694-*101	29/32
MS24694-*102	31/32
MS24694-*103	1-1/32
MS24694-*104	1-3/32
MS24694-*105	1-5/32
MS24694-*106	1-7/32
MS24694-*107	1-9/32
MS24694-*108	1-11/32
MS24694-*109	1-13/32
MS24694-*110	1-15/32
MS24694-*111	1-17/32
MS24694-*112	1-19/32
MS24694-*113	1-21/32
MS24694-*114	1-23/32
MS24694-*115	1-25/32
MS24694-*116	1-27/32
MS24694-*117	1-29/32
MS24694-*118	1-31/32
MS24694-*119	2-1/32
MS24694-*120	2-3/32
MS24694-*121	2-5/32
MS24694-*122	2-7/32
MS24694-*123	2-9/32
MS24694-*124	2-11/32
MS24694-*125	2-13/32
MS24694-*126	2-15/32
MS24694-*127	2-17/32
MS24694-*128	2-19/32
MS24694-*129	2-21/32
MS24694-*130	2-23/32
MS24694-*131	2-25/32
MS24694-*132	2-27/32
MS24694-*133	2-29/32
MS24694-*134	2-31/32
MS24694-*135	3-1/32

.3125-24 UNF-3A44 part numbers

Part no.	Length, in
MS24694-*137	11/32
MS24694-*138	13/32
MS24694-*139	15/32
MS24694-*140	17/32
MS24694-*141	19/32
MS24694-*142	21/32
MS24694-*143	23/32
MS24694-*144	25/32
MS24694-*145	27/32
MS24694-*146	29/32
MS24694-*147	31/32
MS24694-*148	1-1/32
MS24694-*149	1-3/32
MS24694-*150	1-5/32
MS24694-*151	1-7/32
MS24694-*152	1-9/32
MS24694-*153	1-11/32
MS24694-*154	1-13/32
MS24694-*155	1-15/32
MS24694-*156	1-17/32
MS24694-*157	1-19/32
MS24694-*158	1-21/32
MS24694-*159	1-23/32
MS24694-*160	1-25/32
MS24694-*161	1-27/32
MS24694-*162	1-29/32
MS24694-*163	1-31/32
MS24694-*164	2-1/32
MS24694-*165	2-3/32
MS24694-*166	2-5/32
MS24694-*167	2-7/32
MS24694-*168	2-9/32
MS24694-*169	2-11/32
MS24694-*170	2-13/32
MS24694-*171	2-15/32
MS24694-*172	2-17/32
MS24694-*173	2-19/32
MS24694-*174	2-21/32
MS24694-*175	2-23/32
MS24694-*176	2-25/32
MS24694-*177	2-27/32
MS24694-*178	2-29/32
MS24694-*179	2-31/32
MS24694-*180	3-1/32

.375-24 UNF-3A44 part numbers

Part no.	Length, in
MS24694-*181	13/32
MS24694-*182	15/32
MS24694-*183	17/32
MS24694-*184	19/32
MS24694-*185	21/32
MS24694-*186	23/32
MS24694-*187	25/32
MS24694-*188	27/32
MS24694-*189	29/32
MS24694-*190	31/32
MS24694-*191	1-1/32
MS24694-*192	1-3/32
MS24694-*193	1-5/32
MS24694-*194	1-7/32
MS24694-*195	1-9/32
MS24694-*196	1-11/32
MS24694-*197	1-13/32
MS24694-*198	1-15/32
MS24694-*199	1-17/32
MS24694-*200	1-19/32
MS24694-*201	1-21/32
MS24694-*202	1-23/32
MS24694-*203	1-25/32
MS24694-*204	1-27/32
MS24694-*205	1-29/32
MS24694-*206	1-31/32
MS24694-*207	2-1/32
MS24694-*208	2-3/32
MS24694-*209	2-5/32
MS24694-*210	2-7/32
MS24694-*211	2-9/32
MS24694-*212	2-11/32
MS24694-*213	2-13/32
MS24694-*214	2-15/32
MS24694-*215	2-17/32
MS24694-*216	2-19/32
MS24694-*217	2-21/32
MS24694-*218	2-23/32
MS24694-*219	2-25/32
MS24694-*220	2-27/32
MS24694-*221	2-29/32
MS24694-*222	2-31/32
MS24694-*223	3-1/32
MS24694-*224	3-3/32

.4375-20 UNF-3A43 part numbers

Part no.	Length, in
MS24694-*225	15/32
MS24694-*226	17/32
MS24694-*227	19/32
MS24694-*228	21/32
MS24694-*229	23/32
MS24694-*230	25/32
MS24694-*231	27/32
MS24694-*232	29/32
MS24694-*233	31/32
MS24694-*234	1-1/32
MS24694-*235	1-3/32
MS24694-*236	1-5/32
MS24694-*237	1-7/32
MS24694-*238	1-9/32
MS24694-*239	1-11/32
MS24694-*240	1-13/32
MS24694-*241	1-15/32
MS24694-*242	1-17/32
MS24694-*243	1-19/32
MS24694-*244	1-21/32
MS24694-*245	1-23/32
MS24694-*246	1-25/32
MS24694-*247	1-27/32
MS24694-*248	1-29/32
MS24694-*249	1-31/32
MS24694-*250	2-1/32
MS24694-*251	2-3/32
MS24694-*252	2-5/32
MS24694-*253	2-7/32
MS24694-*254	2-9/32
MS24694-*255	2-11/32
MS24694-*256	2-13/32
MS24694-*257	2-15/32
MS24694-*258	2-17/32
MS24694-*259	2-19/32
MS24694-*260	2-21/32
MS24694-*261	2-23/32
MS24694-*262	2-25/32
MS24694-*263	2-27/32
MS24694-*264	2-29/32
MS24694-*265	2-31/32
MS24694-*266	3-1/32
MS24694-*267	3-3/32

.500-20 UNF-3A59 part numbers

Part no.	Length, in
MS24694-*270	15/32
MS24694-*271	17/32
MS24694-*272	19/32
MS24694-*273	21/32
MS24694-*274	23/32
MS24694-*275	25/32
MS24694-*276	27/32
MS24694-*277	29/32
MS24694-*278	31/32
MS24694-*279	1-1/32
MS24694-*280	1-3/32
MS24694-*281	1-5/32
MS24694-*282	1-7/32
MS24694-*283	1-9/32
MS24694-*284	1-11/32
MS24694-*285	1-13/32
MS24694-*286	1-15/32
MS24694-*287	1-17/32
MS24694-*288	1-19/32
MS24694-*289	1-21/32
MS24694-*290	1-23/32
MS24694-*291	1-25/32
MS24694-*292	1-27/32
MS24694-*293	1-29/32
MS24694-*294	1-31/32
MS24694-*295	2-1/32
MS24694-*296	2-3/32
MS24694-*297	2-5/32
MS24694-*298	2-7/32
MS24694-*299	2-9/32
MS24694-*300	2-11/32
MS24694-*301	2-13/32
MS24694-*302	2-15/32
MS24694-*303	2-17/32
MS24694-*304	2-19/32
MS24694-*305	2-21/32
MS24694-*306	2-23/32
MS24694-*307	2-25/32
MS24694-*308	2-27/32
MS24694-*309	2-29/32
MS24694-*310	2-31/32
MS24694-*311	3-1/32
MS24694-*312	3-3/32
MS24694-*313	3-5/32
MS24694-*314	3-7/32
MS24694-*315	3-9/32
MS24694-*316	3-11/32
MS24694-*317	3-13/32
MS24694-*318	3-15/32
MS24694-*319	3-17/32
MS24694-*320	3-19/32
MS24694-*321	3-21/32
MS24694-*322	3-23/32
MS24694-*323	3-25/32
MS24694-*324	3-27/32
MS24694-*325	3-29/32
MS24694-*326	3-31/32
MS24694-*327	4-1/32
MS24694-*328	4-3/32

.5625-18 UNF-3A58 part numbers

Part no.	Length, in
MS24694-*330	17/32
MS24694-*331	19/32
MS24694-*332	21/32
MS24694-*333	23/32
MS24694-*334	25/32
MS24694-*335	27/32
MS24694-*336	29/32
MS24694-*337	31/32
MS24694-*338	1-1/32
MS24694-*339	1-3/32
MS24694-*340	1-5/32
MS24694-*341	1-7/32
MS24694-*342	1-9/32
MS24694-*343	1-11/32
MS24694-*344	1-13/32
MS24694-*345	1-15/32
MS24694-*346	1-17/32
MS24694-*347	1-19/32
MS24694-*348	1-21/32
MS24694-*349	1-23/32
MS24694-*350	1-25/32
MS24694-*351	1-27/32
MS24694-*352	1-29/32
MS24694-*353	1-31/32
MS24694-*354	2-1/32
MS24694-*355	2-3/32
MS24694-*356	2-5/32
MS24694-*357	2-7/32
MS24694-*358	2-9/32
MS24694-*359	2-11/32
MS24694-*360	2-13/32
MS24694-*361	2-15/32
MS24694-*362	2-17/32
MS24694-*363	2-19/32
MS24694-*364	2-21/32
MS24694-*365	2-23/32
MS24694-*366	2-25/32
MS24694-*367	2-27/32
MS24694-*368	2-29/32
MS24694-*369	2-31/32
MS24694-*370	3-1/32
MS24694-*371	3-3/32
MS24694-*372	3-5/32
MS24694-*373	3-7/32
MS24694-*374	3-9/32
MS24694-*375	3-11/32
MS24694-*376	3-13/32
MS24694-*377	3-15/32
MS24694-*378	3-17/32
MS24694-*379	3-19/32
MS24694-*380	3-21/32
MS24694-*381	3-23/32
MS24694-*382	3-25/32
MS24694-*383	3-27/32
MS24694-*384	3-29/32
MS24694-*385	3-31/32
MS24694-*386	4-1/32
MS24694-*387	4-3/32

Part number

Notes from the standard

Head angle 99 to 101 degrees. Recess per MS9006. Threads per MIL-S-7742. Head conical surface not eccentric with the body more than .005 total runout.
Maximum two imperfect threads. The shank diameter may increase by .001 over D, measured from the point of tangency of R and the shank, for a distance of 1/32 (as printed on the sheet).
Head marking: low-alloy steel one "X"; corrosion resisting steel one dash; aluminum alloy none. Edges of head may be rounded or straight-sided.
Grip values follow the printed pattern of Table III (a fixed minimum grip for the shortest lengths, then length minus a constant thread length per size); length and grip steps were checked against the printed examples and the first, transition and last rows of each size.
Dimension F (flat) and the absolute minimum head diameter A for 3/8-24 are not legible in the scan and are left null.
As printed in the standard the 10-32 size shows grip 7/64 up to dash 51; the 5/16 and 9/16 sizes carry other length tolerances than the others (see pn_codes.length_tolerance).

Sources

MS24694 Rev. C, 17 Feb 1969 — Screw, Machine, Flat Countersunk Head, 100 Degree, Structural, Cross Recessed, UNC-3A and UNF-3A — dimensions, part numbers and notes. Public domain, distribution unlimited. Notices: 1 27 Oct 1999 Canceled and superseded by NASM24694. The Part Identification Number for MS24694C and the part number for NASM24694 are identical.; 14 Apr 1992 Amendment 1: Magnetic Permeability, line 1: delete "These fasteners" and substitute "Corrosion resistant steel screws shall".

Educational reference only. not approved data. Always consult the applicable SRM, AMM, or AC 43.13-1B and your certifying authority.

Part	Meaning
Format	MS24694-<material letter><dash number>
Example	MS24694-S1 = #8-32 UNC-3A, 9/32 long, cadmium plated low-alloy steel; MS24694-A100 = 1/4-28 UNF-3A, 27/32 long, anodized aluminum; MS24694-C250 = 7/16-20 UNF-3A, 2-1/32 long, passivated CRES
Length tolerance	Printed twice and not consistent: Table III shows +1/32/-0 for short lengths and +1/64/-1/64 for longer lengths (band limits not legible); the sheet text gives +1/32/-1/64 (#8, #10, 1/4, 3/8), +3/64/-0 (5/16, 9/16) and +1/64/-1/32 (7/16, 1/2). Not tabulated per row.
S	Material: cadmium plated low-alloy steel
A	Material: anodized aluminum alloy
C	Material: passivated corrosion resisting steel
Dash	Dash numbers 1-35 (#8-32), 46-90 (#10-32), 92-135 (1/4-28), 137-180 (5/16-24), 181-224 (3/8-24), 225-267 (7/16-20), 270-328 (1/2-20), 330-387 (9/16-18)

MS24694 screw — flat countersunk, 100 degree, structural

MS24694 at a glance

Specification

Dimensions by size

Part numbers and lengths

Part number

What each code means

Notes from the standard

Sources

MS24694 at a glance

Specification

Dimensions by size

Part numbers and lengths

Part number

What each code means

Notes from the standard

Related

Sources