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08-30-2010, 01:34 PM #1
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?
08-30-2010, 02:01 PM #2
08-30-2010, 02:55 PM #3
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.
Last edited by bosleyjr; 08-30-2010 at 07:12 PM. Reason: spelling, punctuation
08-30-2010, 03:00 PM #4
08-30-2010, 03:42 PM #5
per ANSI B92.1
08-31-2010, 05:11 AM #6
The spec is B92.1,I must have typed it in wrong
08-31-2010, 07:34 PM #7
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Wondering if my handbook is outdated?