This is a simple trick most of you probably know already. If a proper size square is not available and you need to make a layout (like on a floor or what have you). A straightedge, a tape measure, chalkline and soapstone is all you need.
Draw out an X with your straightedge and soapstone or for larger layout definitely use a chalkline. Don't worry about making a "90 deg" edit perfect X, the angle is irrelevant. Measure out equal distance marks from the center point along each leg of the X. Now simply run lines intersecting each of your marks in a square/rectangle. You can take these lines out as far as you need (within reason) and measure out a square box and parallel lines as big as you might need. A good rule of thumb is the X needs to be no smaller then 1/2 your intended layout for reasonable accuracy.
Tommyjoking
Don't you mean 90° instead of 45°
"Don't worry about making a 45 deg perfect X"
I had a mentor teach me this in 1969 and it still works.
Thanks
Marshall
Each of the dimensioned lines is 12"
Can you draw a picture and post it?
any pair of non parallel lines will work, you just end up with a rectangle that is increasingly wider than it is tall the closer the lines are to parallel
thks Marshall I screwed up
That right there looks like an omax software drawing for a water jet cnc............hmmmmm.
Hello Tommy, I saw Marshall's example I have also drawn a picture as an example. The 90 would be the first thing that would result. then you could measure equal distances up and across the two legs, draw a line across those two points and end up with a 45. Great trick gentlemen. Best regards, Allan
I run a compass/divider with one leg centered on the intersection of the perpendicular lines and swing the other leg across both lines. Construct a line through those 2 intersections, perfect 45 deg angle, no measuring errors.
Just another way to do it.
fschweighardt
Tommy didn't let us have a compass or dividers. LoL
Yes that works good for making a 45° once you have developed the 90° .
But it don't work unless they are 90°.
If I had a compass and the 90° I would just throw an arc from the vertex out across both rays and then with a radius length larger than half the distance make two intersecting arcs and then just draw the line from there through the vertex and you have your 45° and you can do that time and time again dividing the angle in half each time.
You can make a 90° easy enough with a few arcs as shown on one of your links I noticed you posted, good info for those starting out.
Marshall
that is a neat trick
i have allays used the 3, 4, 5, thing
i wonder if one has an advantage over the other
Hello grizzzly, one interesting thing about a 3.4.5 combo is that it is a ratio and doesn't require a specific unit of standard measure. If I had a number of pieces of banding material, wooden stickers or other pieces of material, I could use a set length of one piece and mark out 3 units with my scrap piece on one "stick", 4 on another , and five on a third piece. Then using these pieces I could layout a "3,4,5 triangle" and have a square corner. Great conversation everyone. Best regards, Allan
aevald
I wish they would add a like button.
I had those same thoughts going through my little brain as I wrote my reply to Grizzly and inadvertently left them out.
Thanks Allan
Marshall
grizzzly
For ease of developing a 90° the trick Tommy gave is the easiest, with the 3,4,5 it is a bit more prone to mistakes as the 3,4,5 is better for checking the 90° angle than making it as the 3,4,5 need to be straight line measurements and all connect at the same time. so as I said it is better for checking than developing. But I have used it before to draw the 90° also.
Good luck
Marshall
i am mostly just bumping this thread back to the top
but in my opinion
after using both for awhile i have found that the 3,4,5, is better for working in tight areas, and for setting vertical stuff
the X trick works great in large areas
That geometry class taken in high school does have practical applications after all. Now, if I could just figure out why I bothered with calculus.
Best regards - Al
Had a hard time with that calculus thing myself, sure do put that geometry to good use though.
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