gate upright spacing maths - Router Forums
Old 05-07-2015, 02:59 AM Thread Starter
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gate upright spacing maths

I'm want to try to build a gate for the front of my house.

The problem I'm having is getting spacing of the vertical lengths worked out. For example, if the gate is 31 1/2" wide and I want 1/2" spacings, with each panel about 4" wide, is there some magical mathematical formula to work out the actual width of each panel?
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Old 05-07-2015, 05:09 AM
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Angie

31˝ / 4˝ = 7 (31˝ = width of gate, 4˝" = panel + ˝" space)

Lose the extra 1/2" in spacing.

Al B

Last edited by boogalee; 05-07-2015 at 05:21 AM.
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Old 05-07-2015, 06:21 AM Thread Starter
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Quote:
Originally Posted by boogalee View Post
.....Lose the extra 1/2" in spacing.
@boogalee
Ah, so I have an impossible calculation without losing the extra. That's fine, thanks Al.

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Old 05-07-2015, 06:38 AM
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...then .5/7=.071... This will give you the amount to add to each 1/2" space. Too small to worry about precision as the panels will shrink, etc... After they're installed.

You could drive yourself nuts by making a spacer .571...but that might take longer than building the gate...

Nick

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Old 05-07-2015, 07:25 AM
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Your gate is 31 1/2" wide. Your slats are 4" wide and you want 1/2" spacing; here is the equation:

X= number of slats, then x-1 = number of 1/2" spaces (assuming you want slats flush at the ends.

Then 4x + 1/2(x-1)=31 1/2

4 1/2x - 1/2 = 31 1/2

4 1/2x= 32

x+ 7.111 Round down to 7 slats which leaves 1/2" left over, split the leftover 1/2" and inset both ends 1/4"
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Old 05-07-2015, 08:21 AM
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There is a French word "Trompe-l'oeil" used in art, furniture design and etc. that serve's well in your situation. The word means something that deceives the eye. So if your spacing pleases (deceives) the eye then you have got it right. Woodwork is a medium where small fractions of an inch really do not matter all that much. As someone above mentioned shrinkage and expansion is going to add imperfection anyway. Most of us call that "character". If your project is a tiny bit off no one will notice.

As an example I helped an engineer friend build a back porch on his home. It was built over an existing framework and was 30 foot long. Treated lumber was used and he drove himself nuts because it was 3/8" out of square. He spent over an hour trying to "find" the problem. The porch is still out of square and nobody knows but him, but it is a great looking porch. LOL
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Old 05-07-2015, 08:41 AM
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Another way is this: your pic shows 10 slats with 9 spaces. Your total width less 9 x the gaps equal how much wood there will be. Divide that by the 10 pieces. If you don't like the result try 9 pieces with 8 spaces or 11 pieces with 10 spaces. It's a little like calculating stair riser height.

Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.

Last edited by Cherryville Chuck; 05-07-2015 at 09:48 AM.
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Old 05-07-2015, 09:12 AM
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Quote:
Originally Posted by boogalee View Post
Angie

31˝ / 4˝ = 7 (31˝ = width of gate, 4˝" = panel + ˝" space)

Lose the extra 1/2" in spacing.
you have 7 panels @4'' and 6 spaces @˝''.. you need to loose/comp for .07 inches per slat... (kinda hard to float that much equally)

8 panels - seven ˝'' spaces would make for 3˝'' panels/slats...

w/ the panels flush to the the outside of the gate frame you will always have one less space than you have slats...
or one more slat than you have spaces...

take the total number of spaces and multiply by ˝''....
subtract that number from the width of the gate...
divide that number by the number of slats....

This would have been the week that I'd have finished chewing thru the restraints...

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Last edited by Stick486; 05-07-2015 at 10:05 AM.
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Old 05-07-2015, 09:46 AM
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Ah, math....yuck....that's why I worked as a Registered Nurse....the calculations were done by the pharmacy department and the doctor. LOL
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Old 05-07-2015, 10:14 AM
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Are the boards actually 4 inches wide? Or, are they actually 3 1/2" but called 1 x 4's?

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