Reply To: Getting things Square
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The square video is good, but if there is any curve to the edge you are using to check “square” then you will still be out of 90 degrees. I have just started getting interested in woodworking (as a hobby) after spending my career (23 years) as a precise measurement (Metrology) person. A good quick check for 90 is using a 3,4,5 triangle, these can be mm, in, cm, m, ft, etc. since it is a ratio. This is also a quick method for making a square and doesn’t require but about 3 units of an edge. Measure 3 units on an edge and strike a line, or just on plywood strike a straight line 3 units long. Go from the end of the 3 unit line and use your square strike a 4 unit line on the face from the edge (if not using an edge align square to line). Measure from the start point of the 3 unit line to the stop point of the 4 unit line (the longest side), it should be 5 units, any deviation from 5 units is how much it is out of 90 degrees (and in which direction you have to move to make it 90). So if the measurement is less than 5 you have to open the angle up, if it is more than 5 you have to close the angle up. Just a little tidbit of info that might help in checking 90 degrees on a square. Edit: also note that you can multiply each side by the same number and maintain the ratio.
- This reply was modified 5 years, 3 months ago by Rudolph Tuten.