Dave Baker wrote:
The Medway Handyman wrote:
Dave Baker wrote:
Martin Bonner wrote:
On Feb 27, 1:10 pm, Arthur 51 wrote:
On 27 Feb, 13:00, Bruce wrote:

Arthur 51 wrote:
Hi all.
I quite fancy douglas fir for my bookshel/cabinet project.
SL Hardwoods have 290mm x 19mm x 3m (finished sizes)
My question is, is 19mm adequate thickness for the verticals
which will be 2.8m high?
Yes, why not? If IKEA can use foil-faced chipboard of that
thickness for similar heights, solid Douglas Fir should not be a
problem at all.
I should have considered that. Thanks.
You did explicitly say "for the verticals", but just to make su
19mm is /not/ adequate for the actual shelves (unless they are about
a foot long, and only holding one layer of paperbacks.
You're joking right? 19mm solid wood boards would be adequate for
bookcase shelves several feet long. I've got a reproduction bureau
with shelves about 1cm thick and 1 metre long and although they do
sag somewhat when fully loaded they can hold a full shelf of books
ok. A 3/4" shelf, i.e. a floorboard in so many words isn't going to
raise much of a sweat with a few pounds of books on it. Without doing
a lot of tedious calculations I'd estimate that they'd be fine at 4'
long regardless of what you put on them and although they might sag a
bit at 6' long a small central vertical prop would solve that easily
enough.
The OP needs...... The Sagulator!
http://www.woodbin.com/calcs/sagulator.htm

Cool

My gut feel was spot on. An 8" deep shelf, 4' long even with 25 lbs of books
per foot is nicely under the target deflection and just goes over it at 5'
long. I also think that 25 lbs per foot is way over what any normal books I
own weigh although you could probably manage it with A4 sized catalogues
like my engine component ones which weigh about 2 lbs per linear inch.
Normal books about 8" high would be half that or less and the shelves would
be ok up to 6' long.

The trickiest part is determining the design load/ft.