This tool can be used to work out the best plate and number of holes to use on a dividing head. It has two built-in dividing head configurations. Firstly there is the "BS-n Style" for BS-0, BS-1 and BS-2 dividing heads. Secondly there is the Arc Euro Trade style for this style of rotary table / dividing combo head. For other variants of dividing head, a "Custom" option exists that allows you to enter the worm ratio and the available hole counts. If you'd like me to add your dividing head as a built-in option, then please get in touch.

If you add a number into the "Custom Divisions" option, then that number of divisions will be shown at the top of the table for convenience.

Where there is nothing listed in the "Circle", "Turns" and "Holes" column for a given number of divisions, then that number of divisions is not possible (or at least not straightforward) with your dividing head. Where the "Holes" column is empty then each division is a whole number of turns of the input handle.

At the moment it doesn't support differential dividing of the sort supported by the BS-2 dividing head. I may add that in the future - let me know if this would be of use to you.