Instructables

How to divide a line into equal parts without measuring

video How to divide a line into equal parts without measuring
This is a trick I read about when trying to get through a woodworking project. I needed to divide a piece of wood into 5 equal sections, and the workpiece divided into a complex fraction. I struggled to work out the math and measurements in my head, and then with a calculator, but every time I marked up the board I was a little bit off.

But then I read about this trick, which allows one to divide any line (or straight object) into equal parts, or evenly spaced sections without directly measuring the line. It uses some basic principles of geometry - but don't worry, no complex math required.

(By the way, please forgive any shop noise and my "umms" this is my first video instructable :^P). If you have any other ideas or suggestions, please share them below in the comments.

The steps

  1. Choose the work-piece that you want to divide
  2. Choose how many sections you want to make
  3. Draw a diagonal line above the line being divided. The line should be divisible by number of sections desired
  4. Mark out equal points along the diagonal line
  5. Use a square / 90 degree angle to draw lines from the points on the diagonal line down to the original work-piece
  6. Done! Your line should now be cut into equal sections

I've used this at least two different ways in my woodworking

  1. To cut workpieces into equal parts, I just cut down the center of the line
  2. To space joints on a workpiece. For example, if I want to make 1/4 inch dado grooves on a workpiece, I draw more lines 1/8 inch to the right and left of my original line, creating a 1/4" mark for my cuts to follow.
jfishel88.22 days ago

Excellent tutorial! I wanted to add that a steeper division line is harder to accurately mark unless you rotate the paper until it becomes horizontal.

Additionally, a shorter division line will help if your square is inaccurate. I use the edges of the paper to get parallel or perpendicular lines, leaving the square out, but that's just the way I learned to draft.

One last thing: Even if you're working with inches, if you have an imperial/metric ruler it can be a whole lot easier to find a good multiple on the metric side!!!

gcow5 months ago

What is the name of this method? My woodworking teacher has asked the class to figure this out.

workislove (author)  gcow4 months ago
Haha, excellent question...but I have no idea if it has a name. It's just a trick someone showed me when I was struggling with spacing out some parts.
pirobot6681 year ago
Very nice indeed. I have gotten 'stuck' trying to divide stuff out too.
logog1 year ago
very nice tip, thx
workislove (author)  logog1 year ago
Thanks!
Viaticus1 year ago
Nicely done
workislove (author)  Viaticus1 year ago
Thanks!
mistyp1 year ago
Super handy, thanks very much!
workislove (author)  mistyp1 year ago
Thanks, glad you liked it!