I am frequently having to do this particular calculation, months apart, and
have to rebuild the wheel each time. Today I attempted to write the damn
thing down as a formula so I could make an Excel spreadsheet for my own use.

The following, in a spreadsheet, worked twice for me today, but there is
likely a better/easier way?

A formula for spacing a given number of same width slats/spindles evenly
between two points:

X = (S - (W*N))/(N + 1)

whe

X = spacing in inches
S = Space to be filled with slats of a desired width
W = Desired width of slat
N = Number of slats desired

Your corrections/better ideas are more than welcome ... the older I get, the
more I am just looking for a way to getting back to making sawdust faster.

--
www.e-woodshop.net
Last update: 7/10/04

On Sat, 2 Oct 2004 18:32:56 -0500, "Swingman"
scribbled:

I am frequently having to do this particular calculation, months apart, and
have to rebuild the wheel each time. Today I attempted to write the damn
thing down as a formula so I could make an Excel spreadsheet for my own use.

The following, in a spreadsheet, worked twice for me today, but there is
likely a better/easier way?

A formula for spacing a given number of same width slats/spindles evenly
between two points:

X = (S - (W*N))/(N + 1)

whe

X = spacing in inches
S = Space to be filled with slats of a desired width
W = Desired width of slat
N = Number of slats desired

Your corrections/better ideas are more than welcome ... the older I get, the
more I am just looking for a way to getting back to making sawdust faster.

Instead of calculating W*N, measure it. If you've got lots of
spindles/slats, it's easy to screw you up if there is the slightest
inaccuracy in the measurement of the width of slats/spindles. Put all
your slats/spindles next to each other & measure the width. Then
divide by the number of slats/spindles plus one to get the spacing.

Luigi
Replace "nonet" with "yukonomics" for real email address
www.yukonomics.ca/wooddorking/antifaq.html
www.yukonomics.ca/wooddorking/humour.html

Luigi Zanasi said:

On Sat, 2 Oct 2004 18:32:56 -0500, "Swingman"
scribbled:

A formula for spacing a given number of same width slats/spindles evenly
between two points:

X = (S - (W*N))/(N + 1)

whe

X = spacing in inches
S = Space to be filled with slats of a desired width
W = Desired width of slat
N = Number of slats desired

Your corrections/better ideas are more than welcome ... the older I get, the
more I am just looking for a way to getting back to making sawdust faster.

Instead of calculating W*N, measure it. If you've got lots of
spindles/slats, it's easy to screw you up if there is the slightest
inaccuracy in the measurement of the width of slats/spindles. Put all
your slats/spindles next to each other & measure the width. Then
divide by the number of slats/spindles plus one to get the spacing.

Or calculate Centerlines for mounting the slats, rather than spacing
between slats. That way, variations in individual slats will not
matter.

I won't modify your formula for that - you're a smart guy! ;-)

FWIW,

Greg G.

"Luigi Zanasi" wrote in message

Instead of calculating W*N, measure it. If you've got lots of
spindles/slats, it's easy to screw you up if there is the slightest
inaccuracy in the measurement of the width of slats/spindles. Put all
your slats/spindles next to each other & measure the width. Then
divide by the number of slats/spindles plus one to get the spacing.

"inaccuracies" in woodworking measurements are inevitable regardless of the
method ... you just do your careful best as in all woodworking. The idea is
to be able to calculate without having to cut a bunch of expensive wood to
do a trial and error method like that.

Not to mention that it's convenient to have the option to change your slat
width as your design may change.

Thanks, in any event.

--
www.e-woodshop.net
Last update: 7/10/04

Swingman wrote:

X = (S - (W*N))/(N + 1)

whe

X = spacing in inches
S = Space to be filled with slats of a desired width
W = Desired width of slat
N = Number of slats desired


In addition to the considerations expressed about inaccuracies and measuring,
you should modify your formula to divide by N - 1 (not N + 1). For example, with
5 slats, there are 4 spaces between them...

JeffB

On Sat, 2 Oct 2004 20:16:49 -0500, "Swingman"
scribbled:

"Luigi Zanasi" wrote in message

Instead of calculating W*N, measure it. If you've got lots of
spindles/slats, it's easy to screw you up if there is the slightest
inaccuracy in the measurement of the width of slats/spindles. Put all
your slats/spindles next to each other & measure the width. Then
divide by the number of slats/spindles plus one to get the spacing.

"inaccuracies" in woodworking measurements are inevitable regardless of the
method ... you just do your careful best as in all woodworking.

Absolutely true.

The idea is
to be able to calculate without having to cut a bunch of expensive wood to
do a trial and error method like that.

Not to mention that it's convenient to have the option to change your slat
width as your design may change.

Ah! I see! You're talking about the design, not the installation. Then
using your formula makes absolute sense. And you get to try out
different #s of spindles. But when it comes to installing them, I
would still use my method. A 1/64th error in fabricating the spindles
means a gap that is off by 1/2 inch if you're using 30 spindles or so.

Luigi
Replace "nonet" with "yukonomics" for real email address
www.yukonomics.ca/wooddorking/antifaq.html
www.yukonomics.ca/wooddorking/humour.html

JeffB said:



Swingman wrote:

X = (S - (W*N))/(N + 1)

whe

X = spacing in inches
S = Space to be filled with slats of a desired width
W = Desired width of slat
N = Number of slats desired


In addition to the considerations expressed about inaccuracies and measuring,
you should modify your formula to divide by N - 1 (not N + 1). For example, with
5 slats, there are 4 spaces between them...


Kinda depends on whether you leave spaces at the ends - like a
baluster.

------------------
| | | | |
------------------
vs.
------------
| | | | |
------------



Greg G.

On Sun, 03 Oct 2004 05:53:59 GMT, JeffB
scribbled:

Swingman wrote:

X = (S - (W*N))/(N + 1)

whe

X = spacing in inches
S = Space to be filled with slats of a desired width
W = Desired width of slat
N = Number of slats desired


In addition to the considerations expressed about inaccuracies and measuring,
you should modify your formula to divide by N - 1 (not N + 1). For example, with
5 slats, there are 4 spaces between them...

Not if he wants spaces beyond the two end spindles. So with 5 slats,
there would be 4 spaces between them and 2 more at each end of the row
of slats.

Luigi
Replace "nonet" with "yukonomics" for real email address
www.yukonomics.ca/wooddorking/antifaq.html
www.yukonomics.ca/wooddorking/humour.html

In article ,
Swingman wrote:
I am frequently having to do this particular calculation, months apart, and
have to rebuild the wheel each time. Today I attempted to write the damn
thing down as a formula so I could make an Excel spreadsheet for my own use.

The following, in a spreadsheet, worked twice for me today, but there is
likely a better/easier way?

A formula for spacing a given number of same width slats/spindles evenly
between two points:

X = (S - (W*N))/(N + 1)

whe

X = spacing in inches
S = Space to be filled with slats of a desired width
W = Desired width of slat
N = Number of slats desired

Your corrections/better ideas are more than welcome ... the older I get, the
more I am just looking for a way to getting back to making sawdust faster.

"Close, but no seegar" applies.

change the denominator to "N-1", and you've got it.

"Close, but no seegar" applies.

change the denominator to "N-1", and you've got it.

Note: with N slats, there are only N-1 spaces _between_ the slats.

--

"Robert Bonomi" wrote in message news:aef9
Note: with N slats, there are only N-1 spaces _between_ the slats.


True. OTOH, if you are putting slats or spindles between two end posts, it
is N+1 as there will be six spaces.

"Robert Bonomi" wrote in message

"Close, but no seegar" applies.

change the denominator to "N-1", and you've got it.

"Close, but no seegar" applies.

change the denominator to "N-1", and you've got it.

Note: with N slats, there are only N-1 spaces _between_ the slats.

"Close, but no seegar".

Note that (n + 1).is the goal.

When positioning spindles between two legs, or bars in a window, you
generally leave a space between the first post/ and the first spindle, and a
space between the last spindle and the last post, therefore you need one
more space than (n-1).

--
www.e-woodshop.net
Last update: 7/10/04

"Luigi Zanasi" wrote in message

Ah! I see! You're talking about the design, not the installation. Then
using your formula makes absolute sense.

You're right, I actually do use it for the "design" stage, particularly when
doing a shop drawing with a CAD program, which I generally do for every
piece I make since I am usually buiilding custom and rarely use plans ...
then it is a matter of implementing the design.

Most of the time I am looking to accurately mark the location of mortices
for a row of spindles/slats on both a top apron and bottom stringer.

And you get to try out
different #s of spindles.

Yes. that's the beauty of having a spreadsheet, you can just plug in the
different options/design.

But when it comes to installing them, I
would still use my method. A 1/64th error in fabricating the spindles
means a gap that is off by 1/2 inch if you're using 30 spindles or so.

There's a better, and more accurate way then that, actually.

I generally take the results of the calculation and make a "story stick"
with the measurements on it, then use that the "story stick" mark the
location of the mortises for the spindles/slats ... that way there is very
little measurement error, particularly if you reference the same post or leg
as the starting point, and it is much faster.

Thanks for the discussion, Luigi.

--
www.e-woodshop.net
Last update: 7/10/04

"Edwin Pawlowski" wrote in message
m...

"Robert Bonomi" wrote in message news:aef9
Note: with N slats, there are only N-1 spaces _between_ the slats.


True. OTOH, if you are putting slats or spindles between two end posts,
it
is N+1 as there will be six spaces.

Exactly ... AAMOF, I don't think I've ever seen spindles/slats between two
posts or legs that started with a slat/spindle next to each posts instead of
a space?

(n+1) is definitely correct for the task at hand.

--
www.e-woodshop.net
Last update: 7/10/04

"Swingman" wrote in message

Most of the time I am looking to accurately mark the location of mortices
for a row of spindles/slats on both a top apron and bottom stringer.



There's a better, and more accurate way then that, actually.

I generally take the results of the calculation and make a "story stick"
with the measurements on it, then use that the "story stick" mark the
location of the mortises for the spindles/slats ... that way there is very
little measurement error, particularly if you reference the same post or
leg
as the starting point, and it is much faster.

I take the top and bottom stringers and clamp them together when making the
marks. That way, if there is an error, the spindle will still be straight
even if it is off by 1/64. I also do the math rather than mark say, every
2". The pencil line can be a huge error when marking 14 slats. Or so I'd
told. I'd never do that myself would I?

I guess I could use a spreadsheet but I take pencil and paper and draw out
(crudely) the spaces and slats: --0--0--0--0--0-- The I make marks as
needed. 1 1/2" spaces with 2" slats is 1.5, 3.5, 5, 7, 8.5, etc. This is
the place where the Lee Valley Saddle Square is the perfect tool for layout.
The only important rule is simplicity. Don't make 1 13/64 slats and end up
with 2 11/16 spaces. The math will drive you crazy and you will be blind
looking at all those little lines on the ruler.

If the slats are adjacent on both ends then n-1
if the slats are adjacent on one end then n
if the slats are spaced on both ends then n+1

Swingman wrote:

"Robert Bonomi" wrote in message


"Close, but no seegar" applies.

change the denominator to "N-1", and you've got it.

"Close, but no seegar" applies.

change the denominator to "N-1", and you've got it.

Note: with N slats, there are only N-1 spaces _between_ the slats.


"Close, but no seegar".

Note that (n + 1).is the goal.

When positioning spindles between two legs, or bars in a window, you
generally leave a space between the first post/ and the first spindle, and a
space between the last spindle and the last post, therefore you need one
more space than (n-1).

"Edwin Pawlowski" wrote in message

I take the top and bottom stringers and clamp them together when making
the
marks. That way, if there is an error, the spindle will still be straight
even if it is off by 1/64. I also do the math rather than mark say, every
2". The pencil line can be a huge error when marking 14 slats. Or so I'd
told. I'd never do that myself would I?

Great minds think alike? ... right now I am looking at six "stringers"
clamped together (top/bottom/top/bottom, etc) that I started marking
mortises on before I quit the shop last night. ;)

AAMOF, here's a picture of the very operation (incomplete) you describe:

http://e-woodshop.net/files/marking.jpg

As you can see, I keep an electric pencil sharpener on the wall hung
workbench where I do most of my marking.

The "story stick", which I make carefully and keep for future use, also
clamped to the stringers, makes marking less error prone.

I guess I could use a spreadsheet but I take pencil and paper and draw out
(crudely) the spaces and slats: --0--0--0--0--0-- The I make marks as
needed. 1 1/2" spaces with 2" slats is 1.5, 3.5, 5, 7, 8.5, etc. This is
the place where the Lee Valley Saddle Square is the perfect tool for
layout.

I use an engineer's square ... I've used a hinge to do the same thing in the
past, but I've been meaning to get one of thse LV Saddle Squares, but just
haven't gotten around to it. Sounds like you like it?

The only important rule is simplicity. Don't make 1 13/64 slats and end up
with 2 11/16 spaces. The math will drive you crazy and you will be blind
looking at all those little lines on the ruler.

That's _precisely_ why I spent the time yesterday doing the formula and
making a spreadsheet. That, and here lately I can't remember the next time
how I did it the last time ... you probably haven't got that 'advanced' yet
(in age). ;)

--
www.e-woodshop.net
Last update: 7/10/04

"Randy" wrote in message
If the slats are adjacent on both ends then n-1
if the slats are adjacent on one end then n
if the slats are spaced on both ends then n+1

While I agree, IME, you will hardly see anything but the last with
spindles/slats in woodworking.

However, it would not be a bad idea, and easy, to add that to the
spreadsheet in the event you would want to do 1 and 2 above ... options,
options!

Thanks!

--
www.e-woodshop.net
Last update: 7/10/04

If you have cad program, why aren't you just using the "segment" command?

Swingman wrote:

"Luigi Zanasi" wrote in message


Ah! I see! You're talking about the design, not the installation. Then
using your formula makes absolute sense.


You're right, I actually do use it for the "design" stage, particularly when
doing a shop drawing with a CAD program, which I generally do for every
piece I make since I am usually buiilding custom and rarely use plans ...
then it is a matter of implementing the design.

Most of the time I am looking to accurately mark the location of mortices
for a row of spindles/slats on both a top apron and bottom stringer.


And you get to try out
different #s of spindles.


Yes. that's the beauty of having a spreadsheet, you can just plug in the
different options/design.


But when it comes to installing them, I
would still use my method. A 1/64th error in fabricating the spindles
means a gap that is off by 1/2 inch if you're using 30 spindles or so.


There's a better, and more accurate way then that, actually.

I generally take the results of the calculation and make a "story stick"
with the measurements on it, then use that the "story stick" mark the
location of the mortises for the spindles/slats ... that way there is very
little measurement error, particularly if you reference the same post or leg
as the starting point, and it is much faster.

Thanks for the discussion, Luigi.

"Randy" wrote in message
If you have cad program, why aren't you just using the "segment" command?

A distinct possibility, and a good point.

However, said CAD program is not available in the shop, the formula works
quickly with my shopbench calculator which does woodworking fractions, and
the spreadsheet works on a PDA, which is easily available in the shop.

Last but not least, I've just in the recent past gained enough proficiency
on my meager CAD program (QuickCAD) to make good shop drawings ... IOW, I am
more interest in making sawdust than in being a proficient CAD jockey. ;)

--
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Last update: 7/10/04

classic fencepost error....

wrote in message

classic fencepost error....

LOL. You're right ... we always put barbed wire fence posts for cattle at
16.5'. Also a good way to measure distance later on, if you are consistent.

My punishment for my many and frequent transgressions as a kid was give me "
....another mile of fence', or " ... another 200' feet of field line for the
septic systems'.

--
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Last update: 7/10/04

Mine was holes for trees.

Swingman wrote:
wrote in message

classic fencepost error....


LOL. You're right ... we always put barbed wire fence posts for cattle at
16.5'. Also a good way to measure distance later on, if you are consistent.

My punishment for my many and frequent transgressions as a kid was give me "
...another mile of fence', or " ... another 200' feet of field line for the
septic systems'.