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Forum topic by DIYWaterDog posted 07-05-2017 11:04 PM 664 views 0 times favorited 17 replies Add to Favorites Watch
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DIYWaterDog

38 posts in 266 days


07-05-2017 11:04 PM

Hey All,

Looking for some help.

See the images below for dimensions and project space.

So… I have need for more storage space and have some dead space in a corner of the garage. I would like to build some triangle shaped/framed shelving that will be mounted to two of the walls.

My plan is probably 3 shelves total.

One Large shelf will be built above the door jam of the man door (left edge) to the garage door frame.

Two smaller shelves will be built from the right edge of the man door to the garage door frame.

My problem is what will the miter cuts be as marked in the images? I will connect in the corner with a butt joint or 45 degree cuts.

Also, do you think anchoring to the two walls will be enough support for the framing or should I run a vertical support to the ceiling for the larger shelf?

The triangle frames will be built with 3-4 inch wide stock from some salvaged 11 inch wide boards that I will rip to width. The shelf surface will be 1×6 salvaged pine.

Sorry, I did not pay much attention in Geometry class. :-)

Thanks,

DIYWATERDOG

-- Why pay somebody when you can DIY?!?


17 replies so far

View Madmark2's profile

Madmark2

373 posts in 428 days


#1 posted 07-05-2017 11:13 PM

48.6°

M

View DIYWaterDog's profile

DIYWaterDog

38 posts in 266 days


#2 posted 07-05-2017 11:20 PM



48.6°

M

- Madmark2

All the cuts are 48.6°?

May I ask how you come to this number so I understand how this is the number?

-- Why pay somebody when you can DIY?!?

View MrUnix's profile (online now)

MrUnix

6017 posts in 2039 days


#3 posted 07-05-2017 11:26 PM

Once you mark the two side lengths, just snap a line between them – no math needed :)

Or, there are plenty of on-line calculators you can use, like this one: Triangle Calculator

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View dhazelton's profile

dhazelton

2612 posts in 2137 days


#4 posted 07-05-2017 11:27 PM

Why don’t you print out the drawing and put a protractor on it?

View jonah's profile

jonah

1473 posts in 3139 days


#5 posted 07-05-2017 11:29 PM

If you know the length of the sides, use the law of cosines. See here:

http://www.mathwarehouse.com/trigonometry/law-of-cosines-formula-examples.php

View sawdustdad's profile

sawdustdad

335 posts in 725 days


#6 posted 07-06-2017 12:16 AM

53 and 37 degrees on the first diagram

28 and 62 on the second diagram.

Both are right triangles, so the math is very easy. Remember SOHCAHTOA from Trig class?

Sine of the angle is Opposite over Hypotenuse. Cosine is Adjacent over Hypotenuse. Tangent is Opposite over adjacent.

Using the Tangent rule, The tangent of an angle is the ratio of the opposite side divided by the adjacent side. In the first diagram, the top angle, is B/A or 68/51=1.3333. The tan^-1 of 1.3333 is 53.1 degrees.

The hypotenuse is always the side opposite the right angle (corner) so it is the side out in space, so to speak.

Easy math. No need for law of cosines for right triangles.

-- Murphy's Carpentry Corollary #3: Half of all boards cut to a specific length will be too short.

View DIYWaterDog's profile

DIYWaterDog

38 posts in 266 days


#7 posted 07-06-2017 02:42 AM



Once you mark the two side lengths, just snap a line between them – no math needed :)

Or, there are plenty of on-line calculators you can use, like this one: Triangle Calculator

Cheers,
Brad

Thanks! Nice Tool!

- MrUnix


-- Why pay somebody when you can DIY?!?

View DIYWaterDog's profile

DIYWaterDog

38 posts in 266 days


#8 posted 07-06-2017 02:44 AM



Why don t you print out the drawing and put a protractor on it?

- dhazelton

Ha Ha…. you are assuming I own a protractor! I threw that out after Geometry class. :-)

Thanks for the suggestion.

-- Why pay somebody when you can DIY?!?

View DIYWaterDog's profile

DIYWaterDog

38 posts in 266 days


#9 posted 07-06-2017 02:45 AM



53 and 37 degrees on the first diagram

28 and 62 on the second diagram.

Both are right triangles, so the math is very easy. Remember SOHCAHTOA from Trig class?

Sine of the angle is Opposite over Hypotenuse. Cosine is Adjacent over Hypotenuse. Tangent is Opposite over adjacent.

Using the Tangent rule, The tangent of an angle is the ratio of the opposite side divided by the adjacent side. In the first diagram, the top angle, is B/A or 68/51=1.3333. The tan^-1 of 1.3333 is 53.1 degrees.

The hypotenuse is always the side opposite the right angle (corner) so it is the side out in space, so to speak.

Easy math. No need for law of cosines for right triangles.

- sawdustdad

Very helpful… Thanks.

-- Why pay somebody when you can DIY?!?

View AlaskaGuy's profile

AlaskaGuy

3662 posts in 2149 days


#10 posted 07-06-2017 06:03 AM

All you need to know is how to do a google search.

http://www.cleavebooks.co.uk/scol/calrtri.htm

Enter the length if 2 sides and hit calculate. Done.

-- Alaskan's for Global warming!

View Jimintomahawak's profile

Jimintomahawak

57 posts in 316 days


#11 posted 07-06-2017 12:05 PM



Once you mark the two side lengths, just snap a line between them – no math needed :)

Or, there are plenty of on-line calculators you can use, like this one: Triangle Calculator

Cheers,
Brad

Plus 1 for strings

- MrUnix


-- Laziness drives creative thinking...

View dhazelton's profile

dhazelton

2612 posts in 2137 days


#12 posted 07-06-2017 12:25 PM

I started to write that ^ but his question has to do with calculating the miter angles of the frame he’s building to support the shelf, not the shape of the shelf itself.

View DIYWaterDog's profile

DIYWaterDog

38 posts in 266 days


#13 posted 07-06-2017 01:41 PM

Also, do you think anchoring to the two walls will be enough support for the framing or should I run a vertical support to the ceiling for the larger shelf?

-- Why pay somebody when you can DIY?!?

View BurlyBob's profile (online now)

BurlyBob

5070 posts in 2106 days


#14 posted 07-06-2017 01:54 PM

I’d do just as Brad suggested. Keep it simple. Like I taught my kids, “work smart not hard”. Best of luck.

View dhazelton's profile

dhazelton

2612 posts in 2137 days


#15 posted 07-06-2017 11:38 PM

How much weight do you plan on putting on it? Why not just build a free standing rectangular shelf unit to fit that space?

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