How to Measure an Angle

MoonRiver · #1 12/26/14, 08:03 AM

I'm building a console table and the ends will have an X made from 2"x2" boards. Picture a rectangle of 2"x2" with an X dissecting it.

At each corner, the ends of the X have to be cut at an angle to fit. The original plans said 60 degrees, but my table is a little taller than the one in the plans.

How do I figure out the angle size?
How do I cut it? The largest angle on my miter saw is 55 degrees. I also have a circular saw.

How to Measure an Angle - Homesteading Questions

Ozarks Tom · #2 12/26/14, 08:24 AM

I do angles the non-scientific way when the numbers aren't easy. I build the frame, clamp my bracing over it, check it for square, and mark the angles with a pencil. Hard to go wrong, and it doesn't give me a headache.

mmoetc · #3 12/26/14, 08:26 AM

Basic geometry. Maybe this will help.http://www.csgnetwork.com/righttricalc.html

GunMonkeyIntl · #4 12/26/14, 08:32 AM

Trigonometry.
Unfortunately, I didn't keep enough of it from school to do it from memory, so I always end up using a calculator like this one:
www.carbidedepot.com/formulas-trigright.asp

It can sometimes be difficult to figure out which triangle calculator you need to use, so for a project like that, I would probably end up just marking the center of the middle shelf, the middles of the X members, lay the X members in place and mark them from the inside and cut them along the scribed marks. I've used that strategy a bunch of times and it always works.

Beautiful table, by the way. I've got a bunch of reclaimed barn siding that I've been trying to figure out what to do with. May end up building one of those myself.

Edit: didn't realize someone else has answered with a similar calculator while I was typing a response.

mmoetc · #5 12/26/14, 08:40 AM

You can also use a speed square or there are a number of different tools designed to measure angles available on the interwebs.

frogmammy · #6 12/26/14, 10:32 AM

I'm not a guy, so maybe my answer is NOT what you're looking for, BUT...

You say your table is taller. Why not just follow MOST of the original plan (except for leg length), place the cross pieces where the plans call for them, measuring from the top. Would be just like the one in the picture, except the area *under* the last shelf would be taller, which would make it easier to clean under, OR offer additional storage for items in baskets.

Mon

ninny · #7 12/26/14, 11:40 AM

Use my method, cut 15 different boards with different angles and you're bound to have one of them right. Use the one that's right and throw the other 14 in a scrap heap. A $100 table turns into a $1000 table.

Works every time...well, sometimes anyway.

.

MichaelZ · #8 12/26/14, 12:04 PM

You can make this into a Geometry problem. Or, you can take some box cardboard and cutout templates that fit correctly. Then trace onto wood. I am darned good at the math, but I will opt for the latter method every time!

If you do not have the cutoff saw for the angle, mark your cut, tack on a 2x2 next to the mark as a cutting guide, and use a good sharp hand saw. The 2x2 will keep your saw perpendicular.

MoonRiver · #9 12/26/14, 12:13 PM

Quote:

Originally Posted by ninny

Use my method, cut 15 different boards with different angles and you're bound to have one of them right. Use the one that's right and throw the other 14 in a scrap heap. A $100 table turns into a $1000 table.

Works every time...well, sometimes anyway.

.

That appears to be the method I am using. The problem is I have to cut a different angle on each end. Got 1 right and the other wrong. Part of the problem is it's hard to see where my circular saw is cutting.

MoonRiver · #10 12/26/14, 12:16 PM

I'm calling it quits for today. I stained the top and that is looking good, but the angles on the X are getting the best of me. I think I might go with something that doesn't require cutting any angles.

Skandi · #11 12/26/14, 12:36 PM

Angles.jpg

Sorry for the bad paint job!

I've always managed to remember trig becasue my old maths teacher at school taught us a very odd saying to remember the order.
(Sex on hard concrete always hurts the orgasmic areas) that kinda stuck in a 15 yearolds brain!

PS oooh and the angle they join in the middle will of course be different.

Harry Chickpea · #12 12/26/14, 01:19 PM

For reference, the trig mnemonic is the Indian maiden:
SOH CAH TOA
Sine= Opposite over Hypotenuse
Cosine= Adjacent over Hypotenuse
Tangent= Opposite over Adjacent
While that is all well and good, Ozark Tom has the custom fit solution that allows for slight warping or other defects.

The design of the end bracing leaves something to be desired. For stability, only one triangle needs be on an and. The concept of the strength of a triangle is that unless the length of the members change, the angles must remain the same. That second "cripple" triangle actually reduces the strength slightly by damaging the hypotenuse of the solid one, while adding no meaningful strength of its own.

MoonRiver · #13 12/26/14, 02:11 PM

Quote:

Originally Posted by Harry Chickpea

The design of the end bracing leaves something to be desired. For stability, only one triangle needs be on an and. The concept of the strength of a triangle is that unless the length of the members change, the angles must remain the same. That second "cripple" triangle actually reduces the strength slightly by damaging the hypotenuse of the solid one, while adding no meaningful strength of its own.

They are decorative only.

Harry Chickpea · #14 12/26/14, 04:48 PM

I agree. I just think that decorative bits like that have no place on furniture clearly designed for function rather than high art. Getting the angles right on the cripples and then getting them to set right on soft wood without splitting, twisting, or otherwise muck up is not worth the effort when a couple of old LP albums on the ends will accomplish the required task more easily and interestingly.

Personally, on the one diagonal required I would double cut the ends to fit tight in the corners, or just "plate" the ends with scrap veneer. I've no patience with decorative cripples.

Buzz Killington · #15 12/26/14, 06:05 PM

I'd do a variation of MichaelZ's method only make a cardboard template of the inside square of your side. Lay one of your boards in the top and bottom corners where you want them to land and use the template to mark the angle. Use your circular saw to lop off the ends.

I'm a big believer in "I don't care what the angle is or how long it 'should' be," just as long as it fits and works correctly. Math is for engineers.

Nimrod · #16 12/26/14, 08:29 PM

Quote:

Originally Posted by Harry Chickpea

For reference, the trig mnemonic is the Indian maiden:
SOH CAH TOA
Sine= Opposite over Hypotenuse
Cosine= Adjacent over Hypotenuse
Tangent= Opposite over Adjacent
While that is all well and good, Ozark Tom has the custom fit solution that allows for slight warping or other defects.

The design of the end bracing leaves something to be desired. For stability, only one triangle needs be on an and. The concept of the strength of a triangle is that unless the length of the members change, the angles must remain the same. That second "cripple" triangle actually reduces the strength slightly by damaging the hypotenuse of the solid one, while adding no meaningful strength of its own.

I don't buy the argument that the "cripple brace doesn't add to the strength. If there is only one brace, it will keep the end frame of the table a rectangle if it tries to deform in one direction because the brace is under compression. If it tries to deform in the other direction, then the distance between the corners gets bigger and the diagonal brace will be under tension or, more likely, the nails/screws will pull out. Wood is stronger under compression than tension. The cripple will be under compression if the end frame tries to deform the opposite way.

I did the same thing with eye-bolts, cable, and turnbuckles. Run them in an X like the braces and tighten the turnbuckles so that the end frame is square.

If I were doing it your way, I would lay the brace on the end frame, makig sure the frame was square, and draw the cut with a pencil. Make the cut on a motorized miter saw. You can cut off very thin pieces with the motorized miter saw so make the brace a bit longer than needed and trim until it is a tight fit.

Harry Chickpea · #17 12/26/14, 09:18 PM

You are correct that the weak point would be the nails. The cripple attempts to correct that weakness of design and construction using a belt and suspenders approach. Done correctly, both diagonals would be notched to pass at the intersection point, allowing compression in either direction without deforming or pulling weak fasteners. Properly executed (glue and/or proper pegging/tenons/etc. as possibilities), the single triangle is all that is required. The design of any Pratt truss railroad bridge bears that out.

Ozarks Tom · #18 12/26/14, 09:30 PM

To my knowledge, the only geometric shape that can't be forced out of it's original form is a triangle. A single diagonal brace creates 2 triangles in place of a rectangle.

That said, in building our cedar furniture for the porch I did indeed use X bracing, by notching both diagonals to nest into each other at their juncture. A little more work, but then again it's furniture and not a workbench.

po boy · #19 12/27/14, 04:50 AM

Use a t-bevel

MichaelZ · #20 12/27/14, 10:55 AM

Quote:

Originally Posted by Ozarks Tom

To my knowledge, the only geometric shape that can't be forced out of it's original form is a triangle. A single diagonal brace creates 2 triangles in place of a rectangle.

That said, in building our cedar furniture for the porch I did indeed use X bracing, by notching both diagonals to nest into each other at their juncture. A little more work, but then again it's furniture and not a workbench.

Yes, the triangle keeps its shape since the only way it can lose its shape is for two of its sides to change in length. And a single diagonal would work almost as well, but it would not look as nice as an X.