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Cutting triangles

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Forum topic by Stevinmarin posted 1542 days ago 11063 views 2 times favorited 16 replies Add to Favorites Watch
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Stevinmarin

837 posts in 1677 days


1542 days ago

Topic tags/keywords: triangle cutting jig

I’ve been poking around LJ trying to come up with some sort of triangle cutting jig for the table saw. I especially need to cut a perfect equilateral triangle. And then maybe some isosceles triangles. Any simple solutions? Maybe something I can use on my sled?

Steve

-- Entertainment for mere mortal woodworkers. http://www.WoodworkingForMereMortals.com


16 replies so far

View Dennisgrosen's profile

Dennisgrosen

10850 posts in 1717 days


#1 posted 1542 days ago

use a mitre sledge in the oppesite direction
and if you can´t. build a half frame attach it to the mitre sledge
and then sit the sqare pieces against the frame
and cut it right thrugh from corner to corner

Dennis

View Drew's profile

Drew

136 posts in 1702 days


#2 posted 1542 days ago

What kind of triangle?
Right Angled, Obtuse or Acute?

-- That men do not learn very much from the lessons of history is the most important of all the lessons that history has to teach.” ― Aldous Huxley

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Stevinmarin

837 posts in 1677 days


#3 posted 1542 days ago

Well, the equilateral triangle needs equal 60 degree angles. The other one is obtuse. Sort of a squatty one.

-- Entertainment for mere mortal woodworkers. http://www.WoodworkingForMereMortals.com

View rance's profile

rance

4125 posts in 1762 days


#4 posted 1542 days ago

That would be such acute triangle. Hey, someone had to say it.

Steve, for the I saw solice, a tapering jig would get you most of the way there. I’ll think about the equilateral one and maybe get back with you on that one.

(think, think, no… google, google)

This was informative:
http://www.serve.com/hecht/origami/diags/gettri.pdf

Your sled with some blocks taped to it should get you there.

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

View Gary's profile

Gary

1014 posts in 2926 days


#5 posted 1542 days ago

Steve, your idea is close but NOT really something you can use on your sled.
Your sled!
The two best options are either a dedicated sled for each angle OR a sled with a replaceable insert
wherein you can swap out the angle by swapping out the insert.

Check with LJ Darryl Masterson, he’s got it perfected. ;-)

Cheers,
Gary

-- Gary, Florida. http://www.penturners.org/forum/f70/servicepens-2014-a-111967/

View richgreer's profile

richgreer

4522 posts in 1676 days


#6 posted 1542 days ago

What am I missing? – It seems like you set your miter gauge to 30 degrees and make a cut. You flip the board over and make a second cut. Violé – you have an equilateral triangle. Want an isosceles triangle – change the miter angle.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

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Stevinmarin

837 posts in 1677 days


#7 posted 1542 days ago

Rich, you are absolutely right. I think I am overthinking this. I guess my problem lies in my miter guage that is really cheap and crappy and the degree markings are not all that accurate. When I set it up and run my tests on the triangles, they are never accurate. I suppose just buying a good miter guage would save me a lot of trouble!

-- Entertainment for mere mortal woodworkers. http://www.WoodworkingForMereMortals.com

View Dark_Lightning's profile

Dark_Lightning

1671 posts in 1711 days


#8 posted 1542 days ago

If you want a closer angle, go to someplace like Office Depot and get a drafting triangle. There are some fairly large ones- I have a 10” X 10” (on the legs) 45-45-90 triangle, and a 30-60-90 that has one side over 12” long. You can calibrate your miter gauge with it.

View richgreer's profile

richgreer

4522 posts in 1676 days


#9 posted 1542 days ago

Even with a bad miter, you are going to get an isosceles triangle since you would not change the miter setting between the first and second cut. The challenge is getting exactly 30 degrees for an equilateral triangle.

There are ways to measure the angle of your miter without using the scale on the miter gauge.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

View Eli's profile

Eli

141 posts in 1608 days


#10 posted 1542 days ago

Why not make a pattern and flush cut?

View rance's profile

rance

4125 posts in 1762 days


#11 posted 1542 days ago

Steve, Buy an Incra 1000SE, set it up on your saw, and you’ll wonder why you waited so long. Other brands would work, but that’s the one I got. Of course that kinda goes against your mantra(as I see it). I watch your videos and see what you come up with given the substandard tools you use, and I’m inspired. Keep up the good work.

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

View poroskywood's profile

poroskywood

614 posts in 1966 days


#12 posted 1542 days ago

Steve, I just got the Incra 1000SE and rance is right….PERFECTION!
Also I’ve been suggesting the Club technique lately….where you beat the wood into the shape you are looking for.

-- There's many a slip betwixt a cup and a lip.--Scott

View Stevinmarin's profile

Stevinmarin

837 posts in 1677 days


#13 posted 1542 days ago

Dude, count me as a charter member in your club club! My dad used to always say: “If it don’t fit, get a bigger hammer!”

-- Entertainment for mere mortal woodworkers. http://www.WoodworkingForMereMortals.com

View John Gray's profile

John Gray

2370 posts in 2487 days


#14 posted 1542 days ago

Great minds…................................... 8-))

-- Only the Shadow knows....................

View Mark Whitsitt's profile

Mark Whitsitt

86 posts in 1581 days


#15 posted 1542 days ago

Richgreer beat me to it, but I always find it a bit easier to visualize this sort of thing, so I quickly drew this up in Visio…

Note, that the second cut is first flipped along the vertical axis, and then rotated 60 degrees clockwise.

The third cut determines the overall dimensions of the equilateral triangle as defined by the distance “n”.

If you’re paying attention, and very, very careful with measuring, you can get 4 identical equilateral triangles with only two more cuts… you figure it out 8^)

Now, an equilateral triangle is a special case of an isosceles triangle. this means you can use the same technique for any isosceles triangle, whether acute or obtuse; just change your miter angle and final cut dimension.

Other types of triangles would take more complex cuts…

Cheers!
Mark

-- -- "there are many good reasons to use old hand tools, but moral superiority is NOT one of them..."

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