Ansi 92.1 Spline, tolerances definition
2

Question

Ansi 92.1 Spline, tolerances definition

Javy77 (Mechanical)

(OP)

15 Mar 11 00:39

Hello everybody

I need  to specify an internal spline correctly
I am using ansi B92.1 (from machinery's handbook, 28 ed)

the specification is:
FLAT ROOT SIDE FIT
CLASS 5
PITCH 32/64
PRESSURE ANGLE 30 DEG
BASE DIAMETER 0.8931 REF
PITCH DIAMETER 1.0313 REF
MAJOR DIAMETER 1.0734
FORM DIAMETER 1.0665
MINOR DIAMETER 1.000

CIRCULAR TOOTH THICKNESS
MAX ACTUAL 0.0519
MIN EFFECTIVE 0.0491

But a do not know what to use for the tolerances of the  major, minor and form diameter.

Machinery's handbook mentions:
Major diameter  x.xxx  MAX
form diameter   x.xxx
Minor diameter  x.xxx/x.xxx

how do I get these values ?? ,
1) What is the maximum value for major diameter ??
2) Form diameter, is this value the nominal that I obtained ??
3) how I get the min/max value for minor diameter? I just have the nominal value.

Also, I am defining the male spline for this, so I need  the considerations for male spline tolerances,

I really appreciate your help, i have not found information about it.

thanks

Javier

batter1979 (Mechanical) · Answer 1 · 2011-03-15 07:24:32

Buy the standard. And by the way. the major diameter(int)can never be smaller than the major diameter(ext). the most important piece of the puzzle is the tooth thickness. The machinist handbook should not be trusted.

batter1979 (Mechanical) · Answer 2 · 2011-03-15 09:50:49

OR YOU CAN CONVERT YOUR 92.1 TO THE METRIC MODULE AND USE THE PROGRAM I WROTE IN THE THREAD RIGHT BELOW THIS ONE. THEN CONVERT THE #'S BACK TO ENGLISH

tbuelna (Aerospace) · Answer 3 · 2011-03-15 23:32:08

Javy77,

ANSI B92.1-1996 table 16 lists:
major dia ext tol = +.000/-.014"
major dia int = 1.077" max
minor dia ext= 0.975" min
minor dia int tol= +.005/-.000"
form dia = basic dim

Splines designed to earlier revisions of ANSI B92.1 may not fit with those made to the 1996 revision.

I would recommend that you take batter1979's advice and buy the spec., so that you can verify my numbers.

Good luck.
Terry

dinjin (Mechanical) · Answer 4 · 2011-03-17 00:30:25

Batter1979,

I kind of wonder why you chose the pin sizes in your program.
I think it would be difficult to use those inch size multipliers
in the metric system. It would seem to me that you would want to use 1.75 and 2.00 instead of 1.728 and 1.92 as multipliers in the metric system or maybe round up to the nearest quarter or half of a millimeter for the pin sizes.

batter1979 (Mechanical) · Answer 5 · 2011-03-17 13:29:04

you can enter any pin size you want to at the di , and de section to the right in inches

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Ansi 92.1 Spline, tolerances definition
2