Involute Splines & Serrations 30 PA

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Technical Gear Information

Rules &
Formulas

INVOLUTE SPLINES AND SERRATIONS
30° PA

To Get	Having	Rule	Formula
Diametral Pitch	Outer diameter and number of teeth	Divide number of teeth plus 1 by the outer diameter	Pd=N+1/Do
Pitch diameter	Outer diameter and number of teeth	Divide the product of outer diameter and number of teeth by number of teeth plus 1	D=N•Do/N+1
Outer diameter	Diametral pitch and number of teeth	Divide the number of teeth plus 1 by the quotient of number of teeth divided by pitch diameter	Do=N+1/(N/d)
Diametral pitch	Internal diameter and number of teeth	Divide number of teeth minus 1 by the internal diameter	Pd=N-1/D
Internal diameter	Diametral pitch and number	Divide number of teeth minus 1 by	Di=N-1/Pd

STANDARD SAE
PARALLEL KEY SPLINE

NO. of Keys	Space Width Internal	A Fit Permanent Fit		B Fit To Slide Not Under Load		C Fit To Slide Under Load		Nominal Major Diameter
NO. of Keys	Space Width Internal	WD	Minor	WD	Minor	WD	Minor	Nominal Major Diameter
4 6 10 16	0.241D 0.250D 0.156D 0.098D	0.075D 0.050D 0.045D 0.045D	0.850D 0.900D 0.910D 0.910D	0.125D 0.075D 0.070D 0.070D	0.750D 0.850D 0.860D 0.860D	0.100D 0.095D 0.095D	0.800D 0.810D 0.810D	To 3" To 3" To 6" To 6"

POINT WIDTH CONVERSION FOR
STRAIGHT SIDED SPLINE

		EXAMPLE
	N= # of Keys B=180°/N SIN A= KW/RD C= B-A PW= RD X SIN “C” N=6 KW= .371 RD= 1.271	B= 180/6= 30° SIN “A”= .2919 A= 16.97151° C= 13.02849 SIN “C”= .22543 W= 1.271•.22543 PW= .2865

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Reprinted from Ash Gear & Supply
Omni Gear and Machine Corporation - 90 Bissel Street - Joliet, Illinois 60432
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