tata 0 Report post Posted March 6 I have a rotary table with a 90 To 1 reduction and also 4 division plates which cover a wide range of holes can any body tell how to work out the number of holes to use so that I can divide this into 100 so that I can scribe that l can scribe the lines I know that I need to turn 3.6 degrees so less than a full turn of the handle Quote Share this post Link to post Share on other sites
herminsulbonus 0 Report post Posted March 6 YOu need to get a copy of the Workshop Practice Series book Dividing. All is revealed in there. Including that 100 divisions on a 90:1 ratio dividing head can be achieved by moving 18 holes at a time on a circle of 20 holes. Or a multiple thereof, such as 36 holes on a 40 hole circle. Or 72 holes on an 80 hole circle. Or you can work it out: 90/100 x number of holes in the circle. Answer of course must be a whole number as you cant move half a hole etc. It gets complicated. Best to get the book. Also there are online spreadsheets and charts. Be wary of the Vertex chart, it contains errors but I forget for which divisions. Quote Share this post Link to post Share on other sites
noemiebear 0 Report post Posted March 6 One way to do this is to use a digital protractor or angle finder to measure the angle of the divisions on your plates, and then divide 360 degrees by that angle. Make sure to have no issues with your rotary table drill. For example, if your plates have 18 divisions, each division is 20 degrees. So, to divide into 100, you would need to turn 5 degrees for each scribed line. Another option is to use a calculator or software that can help you calculate the number of holes to use. I hope this helps, and good luck with your project! Quote Share this post Link to post Share on other sites
