What is this Major Spline Diameter?

# Thread: What is this Major Spline Diameter?

1. Hot Rolled
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## What is this Major Spline Diameter?

Spline data says:
External Spline to fit internal stub tooth spline
Flat root-Side fit
12 Teeth 32/64 Pitch
.375 Pitch Diameter-30' Pressure
angle per ANSI B92.2-1996

Guys over at the gear house are telling me to turn them to .405/.406
When I calculate per the handbook I am coming out with a number about .004 smaller.I'm sure these guys are right as they do this kind of stuff all day long but since I have never used this place before I want to be certain.
Anyone know what the major diameter should be?

Involute Gear and Spline Software
JR

3. Originally Posted by Metal Slave
Spline data says:
External Spline to fit internal stub tooth spline
Flat root-Side fit
12 Teeth 32/64 Pitch
.375 Pitch Diameter-30' Pressure
angle per ANSI B92.2-1996

Guys over at the gear house are telling me to turn them to .405/.406
When I calculate per the handbook I am coming out with a number about .004 smaller.I'm sure these guys are right as they do this kind of stuff all day long but since I have never used this place before I want to be certain.
Anyone know what the major diameter should be?
First, Isn't SAE B92.2M for metric? I think that the spec you want is SAE B92.1, which is in inch measure.

I think that the pressure angle is 30° , not 30'. (to get the degree sign, hold down the alt key and type 0176 on the numeric keypad).

For flat root, side fit, 30° PA, 12 teeth, 0.375 pitch diameter,

D=N/P, or so diametral pitch is 32 consistent with your pitch and stub pitch diameters of 32/64, consistent with the spec.

The major diameter for an external spline is

Do = (N+1)/P = 0.4063" consistent with your calculation.

There is "Form Diameter" and clearance (Cf=0.001D, or 0.0041 in this case), so check the spec and get the experts here to confirm, but I think that you got your OD right and it should be 0.406. To check, the internal spline major diameter (root) I calculate for this setup is:

Dri = (N+1.35)/P = 0.4172. Your external spline OD of 0.4063", plus the tolerance of 0.0041, gives you 0.4104", which is less than 0.4172 by 0.0068 inches. That is, you have 3 thousandths clearance on this unit. I can't see why you'd use less than 0.406 on the OD.

But check with experts. I'd been researching involute splines for a drill press quill. My source was page 2071 et seq. of Modern Machine Shop's Handbook for the Metalworking Trades, and this book cites the 92.1 specification.

J
Last edited by bosleyjr; 08-30-2010 at 06:12 PM. Reason: spelling, punctuation

4. Originally Posted by JRIowa
Involute Gear and Spline Software
JR
Eval version diametral pitch must be less than 27 or some such. 32/64 not allowed!

5. ## per ANSI B92.1

.392-.406__________________________

6. Hot Rolled
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Thanks guys
The spec is B92.1,I must have typed it in wrong

7. Hot Rolled
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Still a little confused though as the formula I have for a Flat root Side Fit shows
N/P + .8/P -.004

For Fillet Root Side Fit it shows N+1/P

Wondering if my handbook is outdated?

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