FILENAMES: division.xls DESCRIPTION: This is a Microsoft Excel spread sheet with tables of dividing plate hole listings for common ratios used in rotary tables and index heads. Posted by John Stevenson . John provided the following description: ========================================================================== Just lately there has been a number of enquiries on the Ng about division tables for Rotary tables / dividing heads with other than the standard 40 : 1 ratio. The standard series of 3 dividing plates are as follows:- Plate 1 15,16,16,18,19,20. Plate 2 21,23,27,29,31,33. Plate 3 37,39,41,43,47,49. These three plate are suitable for any ratio as all the division breaks down into prime numbers or numbers that are divisible by the holes on the plate. NOTE 1:- For the readers who are going to make their own plates I would miss out the first hole [ 15 ] and move the 21 to the first plate to make room on the second for a 28 hole circle. This is because any numbers need to be divisible by 15 can be handled by 20,21 or 27 and a 28 is handy for 28 and 56 divisions which is not obtainable with some of the non standard rotary tables [ see chart ]. I am posting this information in the metalworking drop box at http://www.metalworking.com This file will be under division.txt and an Excel spreadsheet called division.xls will be with it. The table covers 40, 60, 80 and 90:1 ratios. The first number is complete turns and the fraction is the number of holes on that circle. So 3 21/33 is 3 complete turns and then 21 holes on a 33 hole circle. These are now posted in the Public domain and are free to anyone to use as required. There are NO restrictions on reuse or copying Feel free to use and enjoy. John Stevenson at engineers@btinternet.com Nottingham, England.