Gear Lab


Gear Lab is a collection of gear data calculators in the form of either an iPad or iPhone app that can be used with Worm gears, Helical gears and Spur gears.

Gear Lab has been developed by SpiralArm Consulting Limited and Gear Services (Letchworth) Limited to help in the manufacture of the Worm and Wheel gear sets, Spur gears, Pinions and Helical gears available via the Ultrascale web site. However, it can be used for the same type of gears from other sources.

Version: 2.0.1
Released: 23rd February 2016


Gear Lab Support

The Calculators

The calculators have been developed to help in the Setting up, Production and Checking of the gears available via the Ultrascale web site. Three of the main types of gears are covered, these are Worm gears, Helical gears, and Spur gears. The flow of the app has been setup in such a way as to allow for the calculators to be used on a individual basis, using the minimal of information to output the basic data required, or as a complete process flow from start to finish. For example , starting at the worm then creating a matching worm wheel and then to output the base tangent data to allow the gear to be checked.

The Calculations

The calculations are based on the gear systems Diametral Pitch and Module and assume that you are using standard full depth-teeth.

When calculating the base tangent data, the profile shift coefficient has been fixed at 0 (zero) in order to simplifiy the calculations, However, this does mean that no allowance can be made for corrected gears.

It should be noted that the Metric/Module results that are displayed by the calculators are converted from the Imperial/Diametral Pitch calculations and as a result, there could be some slight variation due to the conversion from Imperial to Metric. However, this should not effect the overall results to any significant degree and therefore should not cause any problems when using the metric results.


The calculators in this app have been tested and no errors have been found, However, no warranty is given or implied for the correctness of the results from the use of these calculators. Therefore, use of these calculators are at your own risk.


Screenshot: iPad app

Data Input

Here you enter the required gear data for the calculations. Some fields are automatically filled when entering data, for example the Diametral Pitch and Module, you can enter either as the other will be automatically converted from whatever is entered.

Data Output

Here the calculated results are displayed after clicking the 'Calculate' option on the bottom toolbar. The results were applicable are displayed in both Imperial and Metric units.


Screenshot: iPad app


Top Button bar
The top button bar as three options. 'Default' - This loads the input data fields with the data preset in the 'Data Entry Defaults' section of the app., 'Select' - This displays a list of input data saved using the 'Save' option. This input data can then be loaded into the input data fields by clicking on it, 'Save' - This saves the currently displayed input data for later use, by using the 'Select' option.

Bottom Toolbar
The bottom toolbar has a number of options depending on the calculator in use at the time. But all calculators have the same basic options. 'Help/Info' - This displays the help for the calculator, 'Calculate' - This calculates and displays the results based on the data entered, 'Clear' - This clears both input and output data from the calculator ready for the next calculation.


Screenshot: iPhone app


The formulas used in the calculations can be displayed by clicking on the letters in the brackets on the left hand side of the screen. This displays a pop-up dialog showing the formula used for that result etc. It should be noted that not all the letters in brackets have a related formula and clicking on them will have no effect.


Screenshot: iPhone app


Each of the main gear sections Worm Gears, Helical Gears and Spur Gears has notation information. Here you will find diagrams outlining the notation used in the calculators in each section along with the notation used in the formulas, It should be noted that the notation used in these calculators for the formulas and the diagrams is non-standard and was created specially for this app to try and make them easier to remember and understand.


Version History

2.0.1 23rd February 2016
Latest iOS
User Interface

iPad compatibility
Persistent input data

Other changes:
Some small bug fixes

1.0.0 6th July 2015
First release


Other apps available in this range

Spur Gear Calculator
This calculator is in the form of either an iPad or iPhone app that can be used to calculate the Outside Diameter, Centre Distance and Ratio of spur gears and pinions.


Gear Lab Pro

Gear Lab Pro is an extended version of the Gear Lab app which will add the calculators and information required for setting up a non-differential hobbing machine to cut both Helical and Spur gears. Those calculators can then be used to workout the likes of the hob setting angle, index change gears and feed change gears required for the hobbing machine.


If you require any further help or information with the use of this app or have any questions about it. Please let us know. Our details can be found on the 'Contact Us' page of this web site.