LOL, well I was going to add mechanical drawing whether on paper or on the
computer. CAD spells this out in a hurry and is easy to fix. Doing it on
a drawing board, you try not to make that mistake a second time.
This is a spreadsheet I devised a few years ago to keep from having to
rebuild the wheel every time I layout spindles/slats between legs,
rails, posts, etc when doing A&C/Mission furniture:
CAVEAT: It has been posted a few times in the past five years and
manages to start an argument every time. It works _perfectly_ for me and
others who have used it for the purpose for which it was intended.
NOTE:I have no intention engaging in argument of any type regarding the
formula, if it doesn't work for someone, they can either roll their own
by tweaking the formula for their specific purpose, or kiss my ass,
whichever suits the time and place...
On Mon, 20 Apr 2009 18:01:46 -0500, Larry Blanchard
As I did the railings around my deck, and ...
I think the confusion is coming in because someone brought centerlines
into the discussion. You can do it with centerlines, you just have to
account for the fact that the measurement to the first centerline from
the edge of the opening is NOT a centerline to centerline measurement.
Put your balusters together, measure (Call this "A"). Then measure the
total distance the balusters go in (Call this "B"). B minus A = "C" &
divide "C" by the number of spaces (probably one more than the number
of balusters). Ta da!!!
On Thu, 23 Apr 2009 23:02:53 -0700 (PDT), email@example.com
Remember that dimension, call it "D", is the width of the opening
between the balusters, not the distance between centerlines. Call the
width of the baluster "W".
From the edge of the opening measure D. From that point measure W.
Those points mark the edges of the baluster. Then repeat the
measurements D & W from the edge of each baluster until you've marked
all the baluster locations.
OR: mark the edge of the first baluster with the dimension "D", then
repeat from that point with the dimension D+W. That locates only one
edge of each baluster, but that's all that's really needed.
OR, and the way I do it is: Cut a couple of spacers with length D and
use them to locate top and bottom of each baluster from the edge of
the opening or from the last baluster installed. Tolerance stackup can
cause perceptible mislocation of the last few balusters installed.
Especially if you work from one end toward the other. Instead, I'll
locate the center baluster(s) and work toward each end from there. If
there are an odd number of balusters, 3, 5, 7, 9, etc. the centerline
of the center baluster will be at the midpoint of the opening. If
there are an even number of balusters, the center of a space between
balusters will be at the midpoint of the opening. Position and install
the center baluster(s) and work from there with the spacer. That cuts
the tolerance buildup and baluster mislocation in half.
...sticks are great! If I'm following myself (and who doesn't like
that?!) I'll use sticks to layout *and* position the posts. If I have
this luxury, then it follows to use said longer sticks as layout
markers for the balusters, then, using the aformentioned smaller
sticks for nailing/screwing helpers becomes really simple...plus
you'll always know where you stand as far as creep goes, there
shouldn't much! If the bay sizes vary, choices have to be made...the
main choice is 'do you want to vary the spaces between balusters from
bay to bay, or keep those spaces the same for the entire job?' Here,
I usually opt for door #2 and keep those spaces the same; letting the
end measurements vary *evenly* side-to-side. This allows me to keep
using the same longer sticks as layout guides, indexing from center
Variation in spacing from bay to bay is more visually objectionable
than a smaller spacing at the ends of bays. The visual flow is already
broken by the boundary of the bay (post, wall, etc.), so there's where
the "odd sized" spaces should be.
Since the maximum baluster spacing is often set by code (don't want
children to get there heads caught between balusters), that makes a
good start point for laying out the pattern.
1. Choose the spacing you want, "D", less than or equal to the code
2. Let the width of a baluster be "W" - assuming all the balusters are
the same width.
3. Calculate the number of balusters in the bay, "N", where the length
of bay = "B": Since the number of spaces is 1 more than the number of
balusters, B = W x N + D x (N+1) and solve for N = (B-D)/(W+D).
4. Since that calculation rarely gives a whole number for "N", round
it up to the next whole number, and you have the number of balusters
for that bay. Round up instead of down so that the end spaces are
smaller than "D" instead of larger than "D".
5. If N is an odd number, the centerline of the center baluster
coincides with the midpoint of the bay. If N is an even number, the
space between the two center balusters is centered on the midpoint of
6. Layout the baluster positions from the centered baluster(s), with
"D" separation, using whatever method pleases you - spacers, story
stick, tape measure, whatever.
Really simple - One decision (width of baluster spacing, D), two
measurements (width of bay, B, and width of baluster, W), and one
simple calculation and the entire bay of balusters is fully defined.
We have a bay 6' 4" long that we want to fill with 1 3/8" balusters
with 3 1/2" open space between balusters.
D = 3.5"
B = 6' 4" = 76"
W = 1.375"
N = (B-D)/(W+D) = (76-3.5)/(1.375+3.5) = 14.871
Rounding N up to the next whole number, N
Since the number of balusters, 15, is odd, the centerline of the
center baluster is centered on the bay (38" from either end), the
clear space between each baluster is 3 1/2", and the clear space
between the end balusters and the end of the bay is 3 3/16".
Calculating the end spacing, 3 3/16", isn't necessary and is left as
an exercise for the reader, if so inclined.
I don't know where you live but before you proceed to far you may wish
to check the building codes. Some have very specific ideas about how
far balusters should be apart. I believe the basic is that a small
child's head should not be able to get his head through the spaces.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.