Any mathematicians out there?

[JR49]

I want to drill 3 EVENLY spaced holes in a 10 inch steel bar. What is the measurement between each hole, and more importantly how did you figure it out

 

[twhite]

Take 10” divide by 4 that will give you 2-1/2” spacing. Mind you that is 2-1/2” from the ends also. To do that type of stuff just divide the length by number of holes plus 1.


Cutting oil is my blood.

 

[Dabbler]

I usually use half the spacing distance at each end for astetic purposes. If you use @twhite spacing of 2 1/2 inches between holes, making 7 1/2 inches, leaving 1 1/4 inches between the centre of the holes to the end.

 

[JR49]

I can’t believe how quickly you responded to me. Also I’m embarrassed that I didn’t figure that out!! Thank you for being smarter than me. JR49

 

[twhite]

I usually use half the spacing distance at each end for astetic purposes. If you use @twhite spacing of 2 1/2 inches between holes, making 7 1/2 inches, leaving 1 1/4 inches between the centre of the holes to the end.

I do too. The question was a very basic one. So I answered in the most basic way. The spacing of holes will turn into a very drawn out discussion in a heartbeat.

Trying to keep it simple on a Monday.


Cutting oil is my blood.

 

[twhite]

I can’t believe how quickly you responded to me. Also I’m embarrassed that I didn’t figure that out!! Thank you for being smarter than me. JR49

Not smarter. Just use that formula a bunch at work.

I personally first figure out where I want my outside holes. Then do that formula for the remainder of the holes. When aesthetics matter and not actual structural requirements are needed.


Cutting oil is my blood.

 

[benmychree]

Method, no math needed; make a mark with a center punch at the center, then take a compass or trammel points and swing an arc on both sides of the center punch mark, the result is 3 equal spaces.

 

[Dan Krager]

There is another scenario that I thought the OP was asking. I drew out some graphical representations of the discussion using a random length. Benmychree's response didn't make any sense about dividing into thirds. That idea is presented in bottom bar of sketch. The next bar up is twhite's response where the center lines of the holes fall on equal thirds. It shows clearly that the bar's length was divided into four equal parts.

However, none of these responses address the difficult issue of how to have equal spaces between the hole diameters as illustrated in the top bar. The third bar up shows how the top bar was "calculated", which can be done with calipers or trammel.



DanK

 

[benmychree]

My take on the original post is that it did not specify the distance from the ends of the bar needing to be equal with the hole center distances, in that scenario, it would be immaterial what the end to first holes was.

 

[verbotenwhisky]

Method, no math needed; make a mark with a center punch at the center, then take a compass or trammel points and swing an arc on both sides of the center punch mark, the result is 3 equal spaces.

Or draw a straight line in AutoCAD 10" long and use the divide command, 4 spaces...