Center of rotation GOST 8742 75. When the center body rotates relative to the stationary center roller, the radial runout of the shank should not be more than
GOST 8742-75*
Group G27
STATE STANDARD OF THE UNION OF THE SSR
MACHINE ROTATING CENTERS
Types and basic dimensions
Machine tool rotary centres. Types and basic dimensions
Introduction date 1978-01-01
Decree State Committee standards of the Council of Ministers of the USSR dated November 14, 1975 N 2915, the validity period is set from 01.01.78
INSTEAD OF GOST 8742-62
* REPUBLICATION (March 1987) with Amendments No. 1, 2, approved in June 1980, December 1982 (IUS 9-80, 3-83).
1. This standard applies to live centers for lathes, including machines with numerical program management(CNC).
2. Centers must be made of two types:
A - with a constant center roller;
B - with a nozzle on the center roller.
3. The main dimensions of the rotating centers must correspond to those indicated in the drawing and in the table.
Type A
Type B
Note. The drawing does not define the design of the centers.
Morse taper | |||||||||
no more | at least |
||||||||
Normal | |||||||||
reinforced | |||||||||
Note. Rotating centers of the normal series can be manufactured with increased accuracy at the request of the consumer. Dimensions on the 2nd row for centers for machine tools with numerical control (CNC).
Example symbol center type A, version 1 with Morse taper 4, normal series:
Center A-1-4-H GOST 8742-75
the same, reinforced series:
Center A-1-4-U GOST 8742-75
The same, normal series of increased accuracy:
Center A-1-4-NP GOST 8742-75
The same for machines with numerical control:
Center A-1-4-H CNC GOST 8742-75
The same, reinforced series for machine tools with numerical control:
Center A-1-4-U CNC GOST 8742-75
The same, normal series of increased accuracy for machine tools with numerical control:
Center A-1-4-NP CNC GOST 8742-75
(Changed edition, Rev. N 1, 2).
4. The center bead of type A centers must have a hardness of at least 59 HRC in length.
5. The nozzle of the centers of type B must have a hardness along the outer cone of at least 59 HRC.
6. The hardness of the seating conical surface of the center bead of type B centers must be at least 51.5 HRC.
7. The Morse taper hardness of the shank must be at least 46.5 HRC.
(Changed edition, Rev. N 2).
8. Morse cones - according to GOST 25557-82 *.
_______________
* Within the territory of Russian Federation valid GOST 25557-2006. - Database manufacturer's note.
9. The radial runout of the cone, the center roller of the center should not be more than:
for normal series | |
for reinforced series |
10. When the center body rotates relative to the fixed center roller radial runout shank should not be more than:
for normal series | |
for normal series with increased accuracy | |
for reinforced series |
Electronic text of the document
prepared by CJSC "Kodeks" and checked against:
official publication
M.: Publishing house of standards, 1988
STATE STANDARD
UNION SSR
MACHINE ROTATING CENTERS
TYPES AND BASIC DIMENSIONS
GOST 8742-75
Official edition
USSR STATE COMMITTEE ON STANDARDS
UDC 621.9-229.335: 006J54 Group G27
STATE STANDARD OF THE UNION S S R
MACHINE ROTATING CENTERS
Types and basic dimensions
Machine tool rotary centers Types and basic dimensions
GOST 8742-62
By the Decree of the State Committee for Standards? * of the Council of Ministers of the USSR dated November 14, 1975 No. 2915, the validity period is set
from 01.01.1978 to 01.01.1983
Non-compliance with the standard is prosecuted * by law
1. This standard applies to live centers for lathes.
2. Centers must be made of two types:
A - with a constant center roller;
B - with a nozzle on the center roller.
3. The main dimensions of the rotating centers must correspond to those indicated in the drawing and in the table.
Official publication Reprint prohibited
* Reissue (December 1980) with Revision No. 1 approved June 1980 (IUS 9-SO).
© Standards Publishing, 1981
Note. The drawing does not define the design of the centers.
Note. Rotating centers of the normal series can be manufactured with increased accuracy at the request of the consumer.
An example of a symbol for a center type A, version 1 with Morse taper 4, normal series:
Center A-1-4-N GOST 8742-75
the same, reinforced series:
Center A-1-4-U GOST 8742-75
The same, normal series of increased accuracy:
Center A-1-4-NP GOST 8742-75
(Introduced additionally, Rev. No. 1).
4. The center bead of type A centers over a length of 1\ must have a hardness of at least HRC 58.
5. The nozzle of the centers of type B must have a hardness on the outer cone of at least HRC 58.
6. The hardness of the seating conical surface of the center bead of type B centers must be at least HRC 50.
7. The Morse taper hardness of the shank must be at least HRC 45.
8. Morse cones - according to ST SEV 147-75.
9. The radial runout of the cone of the center roller of the center should not be more;
for normal series...........O,#12mm
for a normal series of increased accuracy, . . 0.006 mm
for reinforced series............0.010 mm
10. When the center body rotates relative to the stationary center roller, the radial runout of the shank should not be more than:
for normal series...........0.Q30mm
for the normal series of increased accuracy. . . 0.016 mm
for reinforced series .............. 0.040 mm
Editor M. V. Glushkova Technical editor F. I. Shraibshtein Proofreader V. A. Ryaukaite
Rented in emb. 05/05/81 Go, in print. 07.08.S1 0.375 p.l. 0.20 ac.-nzd. l. Tyr. 6000 Price 3 kop.
Order of the Badge of Honor - Standards Publishing House, Moscow, D-557, Novopresnensky per., 3. Vilnius Printing House of Standards Publishing House, 12/14 Mindaugo St. Zach. 1964
Change L 2 GOST 8742-75 Rotating machine tool centers. Types and basic dimensions
By the Decree of the USSR State Committee for Standards dated December 15, 1982, L 4752, the introduction period was established
Item 1. The first paragraph should be supplemented with words; "including for machine tools with numerical control (CNC)";
(Continued see cg, 118)
delete the second paragraph.
Item E. Drawing. 1st A. Execution 2. Exclude size: 2; table. Columns Lai state in a new edition:
(Continued see page 119)
(Continued see* p. 120)
Note to add the paragraph: "Dimensions for the 2nd row for centers for machines with numerical control (CNC)".
Supplement examples of symbols with examples:
“The same * for machines with numerical control:
Center A-1-4-N CLU GOST 8742-75
The same, reinforced series for machine tools with numerical control:
Center A-1-4-U CNC GOST 8742-75
The same, normal series of increased accuracy for machines with numerical control:
Center A-1-4-IL CLU GOST 8742-75 "
Points 4, 5. Change the value: HRC 58 to HRC 9 59.
Item 6. Change the value: HRC 50 to HRC 3 51.5.
Item 7. Change the value: HRC 45 to HRC 3 45.5.
By the Decree of the State Committee of Standards of the Council of Ministers of the USSR dated November 14, 1975 No. 2915, the validity period was established
from 01.01.1978
until 01.01.1983
Non-compliance with the standard is punishable by law
1. This standard applies to live centers for lathes, including machine tools with numerical control (CNC).
2. Centers must be made of two types:
A - with a constant center roller;
B - with a nozzle on the center roller.
3. The main dimensions of the rotating centers must correspond to those indicated in the drawing and in the table.
Note. The drawing does not define the design of the centers.
|
Morse taper |
|||||||||
|
Normal |
|||||||||
|
reinforced |
|||||||||
Note. Rotating centers of the normal series can be manufactured with increased accuracy at the request of the consumer.
Dimensions on the 2nd row for centers for machine tools with numerical control (CNC)
An example of a symbol for a center type A, version 1 with Morse taper 4, normal series:
the same, reinforced series:
The same, normal series of increased accuracy:
The same for machines with numerical control:
The same, reinforced series for machine tools with numerical control:
The same, normal series of increased accuracy for machine tools with numerical control:
(Changed edition, Rev. No. 1,2 )
4. Center bead type A centers on length l 1 must have a hardness of at least HRC e 59.
5. The nozzle of the centers of type B must have a hardness along the outer cone of at least HRC e 59.
6. The hardness of the seating conical surface of the center bead of type B centers must be at least HRC e 51.5.
7. The hardness of the Morse taper of the shank must be at least HRC e 46.5.
8. Morse cones - according to ST SEV 147-75.
9. The radial runout of the cone of the center roller of the center should not be more;
for normal series .............................................................. ............................... 0.0112 mm
for the normal series of increased accuracy .............................................. 0.006 mm
for enhanced series .................................................................. .................................. 0.016 mm
10. When the center body rotates relative to the stationary center roller, the radial runout of the shank should not be more than:
for normal series .............................................................. ............................... 0.0.30 mm
for the normal series of increased accuracy .............................................. 0.016 mm
for enhanced series .................................................................. .................................. 0.040 mm