i know about the square triangle 3-4-5, and I know just how to usage it gain a 90° angle.

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But ns can"t think or recognize how human being use it (accurately) to obtain 90° top top a large plywood sheet.

The most "proper" means that I can think of it note my recommendation edge two points 4 units apart, and using a compass or very static (non strechable) line map two arcs (3 and also 5 units) to get the intersection. However I don"t have any kind of line the I would certainly trust because that that, not any compass large enough (and an accurate enought to reference from an edge instead of a point in a plane) to execute that.

I can have measuring rod 3 and 5 systems in lenght and also just join whatever to get the needed point, however how come accurately note this point if you have the pole on the way?

So, exactly how do you do it properly?

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asked jan 20 "17 in ~ 0:03

Luiz BorgesLuiz Borges
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This is not much off native your initial description, but consider the a set of garden sticks of reputable precision will execute what friend require. Drill a tiny hole in every one at the 1/2" allude (or 1" if friend like) and also again in ~ the appropriate multiple to add the 1/2" or 1" offset. Ar a brad at your zero point, which might be a salvage plank under the sheet of the major surface and place one more brad in ~ the suitable distance. Girlfriend now have two arc-devices i beg your pardon will provide you v the third point when the brad-holes align at the ends.

If precision is required, use your rescue board with the 2 brads and also tap the sheet of the brad into the work-related surface until half the diameter is "buried" to compensate for the thickness that the brad.

You deserve to use any type of material, that course, and also drill feet to your specifications in order to fit the working surface.

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answered january 20 "17 at 0:39

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How execute you use the "3-4-5" dominance to accurately make a square reduced on a paper of plywood?

You don"t. Fine at least, I"ve never used that to cut plywood.

I either use a drywall T-square, or a measuring tape and a chalk heat (working off among the manufacturing facility edges). The 3-4-5 is because that squaring up prebuilt onsite frame or concrete forms (or because that anything much longer than her longest straight edge). It"s for taking the rack out of something; plywood deserve to simply it is in measured and significant in two locations, have actually a line scribed and then cut.

Also, the error tolerance deceases together you boost the multiplier and vice versa; straight edges and carpenter"s squares space going come be more accurate 보다 your ability to 3-4-5-measure-stuff that"s much less than 5".

Meaning, ns wouldn"t use that rule for small stuff, which would be any type of sheet of plywood the doesn"t have actually at the very least one factory edge left, native which the comes more square than any cut I"ve ever before made.

If it doesn"t have actually a factory edge left, (you do one) do your an initial cut, which then becomes her reference allude for further measurements.

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If girlfriend really require them to it is in square and true, a table observed or someone who owns one will certainly be you new best friend.