Using a Chart to Find the Centers of Holes on a Bolt Circle

[TomG]

Just finished a video on using a table to find the centers of holes on a bolt circle. I also created a chart of my own that hopefully is a little easier to use than most that I've seen. The chart is available in the reference section of my website, or near the end of the video.

Tom

[eightball]

Made this coupling bout a year ago. Seems like the od was about 14 inches and the id bout 8 inches. 1 1/2 or 2 inch key. Anyways the one running had 20 mm bolts and the new jackshaft had 22 mm holes. these were supposed to be body fit bolts. Told em no problem ill just but 2-10 hole bolt circles in it. Our sony readouts will let you program bolt circles but i just did the trig on my trusty texas instrument calculator. Needless to say management was tickled to death. And by the way i still have a chart like yours from when i was an apprentice in tech school. Its very useful when you have an odd number of bolt holes. I've done so many 3,4,6, and 8 hole bolt circles I know the sine and cosine by heart.