1Diametral Pitch
$P_d=\frac{T}{D}=\frac{1}{m}
2Module
$m=\frac{D}{T}=\frac{1}{P_d}
3Standard Tooth Proportions
4Circular Pitch
$P_c=\frac{πD}{T}=πm
6Circular Pitch With Backlash
$P_c=2t+B
7Tooth Thickness With Backlash
$t=\frac{P_c-B}{2}
8Contact Ratio
$C.R.=\frac{\sqrt{(R_o^2-R_b^2)_g}+\sqrt{(R_o^2-R_b^2)_p}-csin\theta}{P_ccos\theta}
9Center Distance
$C=\frac{D_g\pm D_p}{2}$
10Center Distance Given $P_d
$C=\frac{T_g \pm T_p}{2P_d}
11Center Distance Given $P_c
$C=\frac{P_c(T_g \pm T_p)}{2π}
12Center Distance Given Module
$C=\frac{m(T_g \pm T_p)}{2}
13Whole Depth
$W_h=a+d=W_r+c
16Power and Tangential Torque
Peanut
$T=F_tr_{driver}
17Total Load
$F_{tot}=\sqrt{F_a^2+F_t^2+F_r^2}
18Radial Load and Pressure Angle
$F_r=F_ttan\phi$
$tan\phi=\frac{F_r}{F_t}
19Axial Load and Helix Angle
$F_a=F_ttan\psi$
$tan\psi=\frac{F_a}{F_t}
20Normal Pressure Angle Relation
$tan\phi_N=tan\phi cos\psi
21Normal Circular Pitch
$P_{cN}=P_ccos\psi
22Normal Diametral Pitch
$P_{dN}=\frac{P_d}{cos\psi}
23Power Worm Gears and Torque
$P=F_{tw}V_w=\frac{NT}{factor}$
$T=F_{tw}r_w
24Worm Helix Angle
$\psi=tan^{-1}\left(\frac{L}{πD_w}\right)$
L=nP
n= single, double, triple
25Separating Force
$F_s=F_{tw}\left(\frac{sin\phi_N}{sin\psi cos\phi_N +fcos\psi}\right)
26Tangential Force of Worm
$F_{tg}=F_s\left(\frac{cos\psi cos\phi_N - fsin\psi}{sin\phi_N}\right)
27Cone Pitch Angle
$tan\gamma_p=\frac{sin\theta}{SR+cos\theta}
28Theta in Cone Pitch
$\theta=\gamma_p+\gamma_g
29Cone Pitch Angle (θ= 90°)
$tan\gamma_p=\frac{1}{SR}$
$90°=\gamma_g+\gamma_p
30Cone Distance
$L=\frac{1}{2}\sqrt{D_g^2+D_p^2}
31Face Width
$b=\frac{L}{3}$
$b=\frac{10}{P_d}$
whichever is lower
32Bevel Gear Axial Force
$F_a=F_ttan\phi sin\gamma_p
33Bevel Gear Radial Force
$F_r=F_ttan\phi cos\gamma_p
34Torque Bevel Gear
$T=F_tr_{mean}
35Mean Radius Bevel
$r_{mean}=\frac{D_p-bsin\gamma_p}{2}
36Outside Diameter for Pinion
$D_{op}=2a+2$
$D_{op}=\frac{N_p+2}{P_d}
37Tooth Thickness Backlash zero
$t=\frac{P_c}{2}
38Root Diameter PinionBack
$D_{rp}=D_g-2a
39Root Diameter Gear
$D_{rg}=D_g-2d
40Outside Diameter for Gear
$D_{og}=\frac{N_p+2}{P_d}$
$D_{og}=D_g+2a
41Backlash
$B=S-T$
$B=\frac{0.03}{P_d}$ to $\frac{0.04}{P_d}$
$0.035/P_d