A worm gear pair is defined by a standardised theoretical basic rack profile and 7 independent geometric quantities:

1

Module

m_{x} or m_{n}

2

Number of starts of worm

z_{1}

3

Number of teeth of wheel

z_{2}

4

One of the following quantities

d_{a1}, d_{1}, q, γ

5

Center distance

a

6

Worm length

b_{1}

7

Face width wheel

b_{2}

Input with following dialog box:

Input of a parameter or change of a parameter, followed by pressing the Tab key, triggers a calculation with actual input: the user can
see the effect of latest input.

Note that for the worm there is a choice for input of one independent quantity out of the following:

Tip diameter worm

d_{a1}

Reference diameter worm

d_{1}

Diameter quotient

q

Lead angle

γ

Input of a quantity as independent and press the Tab key to calculate the others as dependent quantities.
The lead angle γ can be entered expressed in sexagesimal or in decimal degrees.
Input of center distance a is optional, on no entry the center distance is considered as dependent quantity.
Alternatively, the profile shift coefficient for wormwheel x_{2} can be entered, the center distance is then
considered as dependent quantity. The application calculates the minimum and maximum applicable center distances, while keeping the
profile shift coefficients in range. The minimum and maximum profile shift coefficients in function of the flank form are displayed
in the dialog box.

Still required input: face width at root of wormwheel b_{2} and crown width of wormwheel b_{c2}
and some other design dimensions for the wormwheel crown. This is all done as shown in the following dialog box:

Mean normal backlash and backlash tolerance

The application allows the backlash to be apportioned over the worm with a scale from 0 to 100 %. Selection is done
by means of a trackbar. The rest percentage is then apportioned to the wormwheel.
Results of geometry calculation in table form looks like: