GOST 6111-52 Tapered Inch Thread with 60° Thread Angle

State Standard of the Union of Soviet Socialist Republics

Tapered inch thread with 60° thread angle

GOST 6111-52

State Committee of the USSR for Standards

Tapered inch thread with 60° thread angle	GOST 6111-52* Supersedes GOST 20010-38

Approved by the Standardization Directorate under the Council of Ministers of the USSR on January 10, 1952. Effective date: October 1, 1952.

Reviewed in 1984.

This standard applies to threaded connections of fuel, oil, water, and air pipelines in machines and machine tools.

Notes:

1. In pipelines made of steel water-and-gas pipes per GOST 3262-75, tapered thread connections shall be made per GOST 6211-81.

2. (Deleted, Amendment No. 2).

I. Dimensions

1. The profile and dimensions of the tapered inch thread with a 60° thread angle shall comply with Fig. 1 and Table 1.

Table 1

Thread size designation	Number of threads per 1”	Size in mm
		Thread pitch	Thread length		Thread diameter in the gauge plane			Minor diameter of thread at pipe end	Working height of thread
			working	from pipe end to gauge plane
					pitch	major	minor
inches	n	P	l₁	l₂	d₂=D₂	d=D	d₁=D₁	dT	H
¹/₁₆	27	0.941	6.5	4.064	7.142	7.895	6.389	6.135	0.753
¹/₈	27	0.941	7.0	4.572	9.519	10.272	8.766	8.480	0.753
¼	18	1.411	9.5	5.080	12.443	13.572	11.314	10.997	1.129
³/₈	18	1.411	10.5	6.096	15.926	17.055	14.797	14.416	1.129
½	14	1.814	13.5	8.128	19.772	21.223	18.321	17.813	1.451
¾	14	1.814	14.0	8.611	25.117	26.568	23.666	23.128	1.451
1	11½	2.209	17.5	10.160	31.461	33.228	29.694	29.059	1.767
1¼	11½	2.209	18.0	10.668	40.218	41.985	38.451	37.784	1.767
1½	11½	2.209	18.5	10.668	46.287	48.054	44.520	43.853	1.767
2	11½	2.209	19.0	11.074	58.325	60.092	56.558	55.866	1.767

Notes:

1. When the pipe and coupling with nominal thread dimensions are screwed together without interference, the gauge plane of the pipe thread coincides with the face of the coupling.

2. Dimension dT is for reference.

3. Instead of the ¹/₁₆” thread, M6×1 tapered thread per GOST 19853-74 may be used.

4. The number of full-profile threads in the thread engagement shall not be less than two.

5. The dimension l₂ (distance from the gauge plane to the pipe end) may be reduced, provided that the requirement of clause 4 of this standard regarding the difference between dimensions l₁ and l₂ is observed.

Fig. 1

The thread pitch is measured parallel to the thread axis.

The bisector of the thread angle is perpendicular to the thread axis.

Designation of a 3/4” tapered thread: K³/₄” GOST 6111-52.

(Revised edition, Amendment No. 2).

II. Tolerances

2. The pipe thread (external thread) is checked by pitch diameter using a ring thread gauge per GOST 6485-69. The axial displacement of the pipe gauge plane Δl₂ (Fig. 2) relative to the nominal position shall not exceed ±P (thread pitch).

Fig. 2

(Revised edition, Amendments No. 1, 2).

3. The coupling thread (internal thread) is checked by pitch diameter using a plug thread gauge per GOST 6485-69. The axial displacement of the coupling gauge plane Δl₂ (Fig. 3) relative to the nominal position shall not exceed ±P (thread pitch).

Fig. 3

(Revised edition, Amendments No. 1, 2).

4. The difference between dimensions l₁—l₂ shall be not less than the difference between the nominal dimensions l₁ and l₂ specified in Table 1.

5. The deviation of the crest and root distances of the pipe and coupling thread from the pitch diameter line (δh₁ and δh₂ per Fig. 4) shall not exceed the values given below.

Table 2

Thread size designation	h₁=h₂=¹/₂H₁	δh₁=δh₂
	mm
¹/₁₆ and ¹/₈”	0.3765	-0.045
¹/₄ and ³/₈”	0.5645	-0.065
¹/₂ and ¾”	0.7255	-0.085
1 - 2”	0.8835	-0.085

Fig. 4

(Revised edition, Amendment No. 2).

6. Deviations of the half thread angle, taper angle (φ/2), and thread pitch deviation (deviations in distance between any threads) shall not exceed the values given below.

Table 3

Thread size designation, inches	Limit deviation
	of half thread angle	of taper angle		in thread pitch
		for external thread	for internal thread	over a length up to 10 mm	over a length above 10 mm
				mm
¹/₁₆ and ¹/₈”	±1°	+12°	-12°	±0.02	±0.04
		-6°	+6°
¹/₄- 2”	±45°	+10°	-10°
		-5°	+5°

(Revised edition, Amendments No. 1, 2).