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Finding X leg angles

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Forum topic by PhillipRCW posted 04-21-2017 09:49 PM 1112 views 0 times favorited 19 replies Add to Favorites Watch
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PhillipRCW

458 posts in 1101 days


04-21-2017 09:49 PM

Has anyone worked with any online tools to help determine the correct angles of X legs? I was hoping to find something, but have so far not found anything worth while.

-- Phillip- Measure twice, cut onc.... Hey look, it's rustic.


19 replies so far

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darinS

705 posts in 2703 days


#1 posted 04-21-2017 10:23 PM

Phillip,

Would something like one of these work for you? I would think it would just be trigonometry unless I am misunderstanding what you are trying to do.

http://www.calculatorsoup.com/calculators/trigonometry/

-- They say many people die because of alcohol. They never realized how many of them are born because of it.

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Rick_M

10619 posts in 2216 days


#2 posted 04-22-2017 01:15 AM

There was a big discussion about this, maybe 2 years ago. The math is deceptively complex. Seems like it should be simple but isn’t. The easiest ways are a drawing program or laying them out full size.

-- http://thewoodknack.blogspot.com/

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PhillipRCW

458 posts in 1101 days


#3 posted 04-22-2017 02:04 AM



There was a big discussion about this, maybe 2 years ago. The math is deceptively complex. Seems like it should be simple but isn t. The easiest ways are a drawing program or laying them out full size.

- Rick M


Yeah, I love math, but it can definitely get crazy.

-- Phillip- Measure twice, cut onc.... Hey look, it's rustic.

View DirtyMike's profile

DirtyMike

637 posts in 738 days


#4 posted 04-22-2017 02:25 AM

I Just use 2 scrap 2×4s, measure the width of table top and scribe 2 lines. Defiantly a measure twice cut once situation.

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jbay

1856 posts in 735 days


#5 posted 04-22-2017 02:38 AM

The math is over my head, Sketchup, it only takes a few minutes.
I did find this, (if it works) There is a calculator on the right side you can try.
http://jsfiddle.net/h1xda7qm/

-- If anyone would like to see my Portfolio, PM me and I would be glad to send you the link.

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Monte Pittman

27068 posts in 2174 days


#6 posted 04-22-2017 03:56 AM

On the table I am building, I didn’t do any math. I laid them with my desired height and span, marked them. Worked for me anyway.

-- Mother Nature created it, I just assemble it.

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PhillipRCW

458 posts in 1101 days


#7 posted 04-22-2017 07:51 AM



On the table I am building, I didn t do any math. I laid them with my desired height and span, marked them. Worked for me anyway.

- Monte Pittman


Any pictures of the current work Monte?

-- Phillip- Measure twice, cut onc.... Hey look, it's rustic.

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jbay

1856 posts in 735 days


#8 posted 04-22-2017 03:43 PM

Is this not what you are looking for? ( http://jsfiddle.net/h1xda7qm/ )
If not, what are you trying to find?

-- If anyone would like to see my Portfolio, PM me and I would be glad to send you the link.

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diverlloyd

2332 posts in 1693 days


#9 posted 04-22-2017 04:53 PM

The math is easier to understand if you realize that it’s for making a triangle and the board is the hypotenuse of said triangle. After that you can use a calculator and use the rise and run function of it. Instead of having to use the sin and cos buttons which are confusing with out knowing the formulas.

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Rick_M

10619 posts in 2216 days


#10 posted 04-22-2017 05:27 PM

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diverlloyd

2332 posts in 1693 days


#11 posted 04-22-2017 06:45 PM

Jbays pic shows what I’m saying all he is doing is making a triangle with rise and run and the board is the hypotenuse. So on a calculator( I use a sheet metal union calculator but any with a rise and run function will work) you punch the rise and run in and then it gives the length and degree of hypotenuse. Just remember that a triangle has 180 degrees in it. So doing cross bracing your run will be the length between the legs and the rise will be height you putting the brace. So that should be a 90 degree unless your legs are canted we will stay with 90 for the ease of my long explanation. Now 180 – 90 is 90 so your bracing angle cuts should add up to 90. So as in jbays pic the angle is 44.768 degrees so 90 minus that is the angle of the cut used on the bottom to make it flat. Since it’s a right triangle both ends would be the same. Most of the guys in my class had issues with the same thing because they looked at it as being a square but it’s really just a couple triangles making the math a bit easier. I’m not going into sine cosine because it’s confusing and you need to use the memory function on the calc and then you need to know the difference of 0 off 90 and 90 off 0. That really confused my class mates I like math and that is just a pain and if you don’t do it often you forget the steps. It’s easier to show it in person then explain it in words but if your calculator doesn’t have the function just use and internet site that has a plug in. You can brake anything down into a triangle like that to make the math easier once you get used to doing it. I just made a 3ft cut out of Indiana for a client and used the same method of triangulate all the points of the bottom of Indiana to make it accurate. But with that I used two triangles and the used the points where the two hypotenuses met for the points.so now I have all the point measurements I can make another of any size by just using a size ratio. Sounds more complicated then the bracing but it’s the exact same thing just done twice to find a point minus the extra step of the degree cut. Triangles are good for lots of different lay out of shapes. I have three of the sheet metal union calculators that I use and they are the same as the construction calculators you see at the store but they have more hvac features.
That being said Monte has the easiest method for doing braces.

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diverlloyd

2332 posts in 1693 days


#12 posted 04-22-2017 06:48 PM

A guess a pic(jbays) is worth a thousand words sorry I started rambling

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Rick_M

10619 posts in 2216 days


#13 posted 04-22-2017 09:03 PM

My question wasn’t, ‘how did jbay do it?’ Give people some credit. I realize it requires trig to solve and I know why. I wanted to know how you did it with a rise and run calculator because the simple ones I’ve seen won’t do cross bracing but I searched around and found a $70 one that will. The only cross braced table I ever built, I tacked the legs together with a nail, made them to the right width and marked the angle, whatever it was. No measuring, no math, no cadd.

-- http://thewoodknack.blogspot.com/

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diverlloyd

2332 posts in 1693 days


#14 posted 04-22-2017 09:24 PM

With a rise and run calcutlator you put in the rise and then the run the hit the hyp button. That gives you length hit hyp again and it gives you the angle. I guess I gave you to much credit thinking you read the manual with you calculator. So i gave the process with my calc what calc do you have?

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jbay

1856 posts in 735 days


#15 posted 04-22-2017 10:06 PM

”any online tools to help determine the correct angles of X legs?”

^Just for the record, all I was doing was showing the OP what I thought he was asking for.

These days Sketchup would be MY preferred method.
In the past I have done it many other ways, methods as described by Monte, to full scale drawings.
(I never was good with formulas.)

-- If anyone would like to see my Portfolio, PM me and I would be glad to send you the link.

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