gear teeth and spline hub shaft

Another way to drawing gear without mirror feature

only use :

• modulus = m (or DP if you want )
• tooth number = Z
• contact angle = ALPHA (green)

1/ make primitive radius : R = (m * Z)/2  (red point)

2/ make head circle :  RS=  R + m    (green point)

3/ make base circle : RB = R*cos(ALPHA)   (blue point)

First , we calculate the intermediate angle (angle of incidence)

TETA=acos(cos(alpha)*(R/Rs))  (it possible to check it, after in the sketch)

TETA1=tan(ALPHA)-(ALPHA*(pi/180))
TETA2=tan(TETA)-(TETA*(pi/180))
TETA3=TETA1-TETA2

Note : here i use a involute equation 😉

And now, we calculate the tooth thickness

1/ thikness @ primitive circle :  E=(Pi*m)/2  (black line)

2/thikness @ base circle : EB=R1* ( (E/R) +2*TETA1 )  (orange line)

3/ thiknesse @ head circle : T=RS*( (E/R) + 2*TETA3 )   (pink line)

now we can drawing a sketch:

the origin is the contact point of gear pair (green circle)

and finally, you drawing a arc circle with 3 points

obsiouvly, if you use diametral pitch DP  instead modulus

use this  : M * DP =25.4mm

example DP 4   give :

modulus : 25,4/4= 6.35

now we can apply feature at this sketch ( extrude or sweep) and we don't use mirror feature 🤣