How To Cut A Triangle From A Square Board


Leaseman

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It would seem so simple but I can't figure it out. What sort of jig/setup on a table saw do you recommend to cut a triangle out of a 3" x 3" board? I have a two foot board that measures about 3" x 3" square. I need to cut it into a triangle shape, two foot long. It would involve ripping along the blade of course but what type of jig would hold it in place?  It's driving me crazy! Any ideas?

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Make one cut then tape the offcut back in place and make the other cut. I guess more depends on if you want an equilateral triangle or a right triangle ? Maybe an isosceles triangle ? If you need exact cuts tape a shim the thickness of the saw kerf in place, but carefully cleaning up the cut faces with a jointer or a hand plane would work too.

3" rip cuts in hardwood will either take multiple passes or a very sharp rip blade and a powerful motor on your saw , at least 3 hp I would guess.

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Thanks for the reply wdwerker but now sure I'm following you. Lets assume i'm making an equaliteral triangle (all three equal sides). If i'm ripping the board down the table saw it will be laying flat so how would it be cutting off one of the corners? The board will have to sit in a cradle or jig that passing one corner at a time through the blade. Right?

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If I understand it correctly, the base of the triangle will be 24” long and it will be 3” tall and 3” thick? Hopefully you have a bandsaw? If so, on a piece of mdf, or plywood, draw a horizontal line,  24” long. At the mid point, 12”, draw a vertical line that is 3” tall. Connect the 3” tall vertical line to the two outside horizontal points to give you two ea. right triangles. With a compass on similar, determine the other two angles. If you have a bandsaw, let me know and I’ll continue from there. 

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41 minutes ago, wdwerker said:

Blade at 30 degree angle then rip. A large push stick would be smart.  Might be s smart idea to practice on some scrap like 2x4. Clear packing tape carefully applied to reattach the off-cut before you make the second cut.

Yea, I guess this is probably the best way to go. I was just trying to think of alternatives. Thanks for your input.

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That’s not how I envisioned it at all. So the whole length will be 3” high at center point? If that being the case, with the first cut not being the problem child, the second cut will definitely require a jig. I’m thinking, after the first cut, a 1x  screwed to the proposed bottom of the triangle, that will rest on the top of your ts  fence and if your fence isn’t that tall, then add a spacer to make up the difference. In fact, a third piece to the right of your fence, thus saddling the fence between.  Now, the bottom of your triangle is on top and the proposed peak is resting on the ts. A feather board prior to the blade is highly recommended . If that doesn’t make sense, and I can’t imagine why, ;), I will do a sketch tomorrow at work and post it. 

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Everyone seems to be ignoring the suggestion to tape the offcut back in place. Perhaps even adding a 1/8" shim to allow for the lost kerf. Spin the blank end for end and rip again. Depending on the power of the saw and the hardness/density of the wood several passes wtih a successively higher blade might be nessacary.

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