Spur Gear Cutting Formulae
Spur Gear Cutting Formulae
(OP)
Hi all i am new to this forum, my situtation is i am trying to design a spur gear profile for our wire cutter so that we can cut an electrode to spark the porfile of our gear onto the component.
The module is 0.75 and the number of teeth are 41, how the heck do you work out the angle of the teeth etc i think our pressure angle is 20degrees, please help and when i work out my circumference pitch is seems to be way out!!!
My calculations so far:
CP = 2.3562....i get 8.78???
Module = 0.75
PD = 30.75
Addendum = 0.75
Dedendum = 0.8745
Total depth of tooth = 1.625
Tooth thickness = 1.178
OD = 32.25
ID = 29
The module is 0.75 and the number of teeth are 41, how the heck do you work out the angle of the teeth etc i think our pressure angle is 20degrees, please help and when i work out my circumference pitch is seems to be way out!!!
My calculations so far:
CP = 2.3562....i get 8.78???
Module = 0.75
PD = 30.75
Addendum = 0.75
Dedendum = 0.8745
Total depth of tooth = 1.625
Tooth thickness = 1.178
OD = 32.25
ID = 29





RE: Spur Gear Cutting Formulae
RE: Spur Gear Cutting Formulae
email me for a geometry program mikebull@blueyonder.co.uk
RE: Spur Gear Cutting Formulae
I am using solidworks 2008 to design the gear.
I have included a picture to help explain what i mean.
Thanks
RE: Spur Gear Cutting Formulae
The CP is measured at the PD (not the OD) Your tooth thickness at the tip should be .572mm. Your base diameter (BD) is PD*cos(20)=28.8955mm. This is the diameter that you would unwind a string to generate the involute profile. You said nothing about the gear this will mate with. This gear mated with itself on standard centers would have zero backlash. Which is not a recommended practice.
RE: Spur Gear Cutting Formulae
multiply the following by your module:
OD= teeth +2
PCD= teeth
add = 1
basic tooth thickness= 1.5708
the depth of tooth depends on the standard you are working too,the common one is 2.25
cp= (3.141592*module)/ 25.4
ded= depth - add
for a 41 tooth gear of .75 module the OD = 32.25mm, PCD= 30.75mm,ADD=.75mm,T.TH=1.1781 and the depth=1.6875.
hope this helps
RE: Spur Gear Cutting Formulae
SolidWorks usually has a toolbox that generates involute gears & splines. What version are you using?
Ron Volmershausen
Brunkerville Engineering
Newcastle Australia
http://www.aussieweb.com.au/email.aspx?id=1194181
RE: Spur Gear Cutting Formulae
RE: Spur Gear Cutting Formulae