FILENAMES: 21t.BMP DESCRIPTION: This is a CAD drawing of gear designed to fit a Myford lathe. Posted by John Stevenson . John provided the following description: ================================================================= Posted into the drop box at www.metalworking.com is a file called 21teeth.bmp This is a bitmap image of a 21T 20 DP 14.5PA gear, The same as fitted to Myfords as a metric intermediate gear. The genuine CAD produced shape is in blue. The green arcs are the single arcs generated by the method I have described in an article on form tooth gear cutters that is on the Metal Web News site. As you can see from this image there is virtually no difference in the flank radii. What is apparent is the undercutting caused by using a 14.5PA with a low number of teeth. This is why the standards have changed to 20 degrees PA, to prevent this. John Stevenson Nottingham, England.