Gear Rack Tooth Proportions - SDP/SI Tech Library D190-T30

TABLE 1.1 TOOTH PROPORTIONS OF BASIC RACK FOR
STANDARD INVOLUTE GEAR SYSTEMS

Tooth Parameter	Symbol in Rack Fig. 1.6	14-1/2º Full Depth involute System	20º Full Depth involute System	20º Coarse-Pitch involute Spur Gears	20º Fine-Pitch involute System
1. System Sponsors 2. Pressure Angle 3. Addendum 4. Dedendum 5. Whole Depth 6. Working Depth 7. Clearance. 8. Basic Circular Tooth Thickness on Pitch Line 9. Fillet Radius In Basic Rack 10. Diametral Pitch Range 11. Governing Standard: ANSI AGMA	-- f a b h_t h_k C t r_f _-- _-- _--	ANSI & AGMA 14-1/2° 1/P 1.157/P 2.157/P 2/P 0.157/P 1 5708/P 1-1/3 x not specified B6.1 201.02	ANSI 20° 1/P 1.157/P 2.157/P 2/P 0.157/P 1.5708/P 1-112 X not specified B6.1 --	AGMA 20° 1.000/P 1.250/P 2.250/P 2.000/P 0250/P p/2P 0.300/P not specified -- 201.02	ANSI & AGMA 20° 1.000/P 1.200/P + 0.002 2.200/P + 0.002 2.000/P 0.200/P + 0.002 1.5708/P not standardized not specified B6.7 207.06

TABLE 1.2 PREFERRED DIAMETRAL PITCHES

Class	Pitch
Coarse	1/2 1 2 4 6 8 10

Class	Pitch
Medium- Coarse	12 14 16 18

Class	Pitch
Fine	20 24 32 48 64 72 80 96 120 128

Class	Pitch
Ultra-Fine	150 180 200

TABLE 1.3 BASIC GEAR DATA FOR 20° P.A. FINE-PITCH GEARS

Diameter Pitch	32	48	64	72	80	96	120	200
Diameter of Measuring Wire*	.0540	.0360	.0270	.0240	.0216	.0180	.0144	.0086
Circular Pitch Circular Thickness Whole Depth Addendum Dedendum clearance	.09817 .04909 .0708 .0313 .0395 .0083	.06545 .03272 .0478 .0208 .0270 .0062	.04909 .02454 .0364 .0156 .0208 .0051	.04363 .02182 .0326 .0139 .0187 .0048	.03927 .01963 .0295 .0125 .0170 .0045	.03272 .01638 .0249 .0104 .0145 .0041	.02618 .01309 .0203 .0083 .0120 .0037	.01571 .00765 .0130 .0050 .0080 .0030

Note: Outside Diameter for N number of teeth equals the Pitch Diameter far (N+2) number at teeth.
*For 1.7290 wire diameter basic wire system.