Will this prevent any sagging at least for 10 years, if not 20+?

Basic idea.
I am building a bookcase primarily of hickory for my reference library. The library consists of the Oxford English Dictionary, Great Books of Western Civilization, various books on programming languages, ...

Calculations of load.
Many of the shelves will be loaded with books for full 4' length and books of 12.5 inches tall by 10 inches wide. That gives a total volume of 6000 cubic inches or 98322.384 cubic centimeters. Based on the specific gravity of paper of 1.2 grams/cubic centimeter, that yields a load of just over 260 pounds. Allowing for 10% safety margin, that is about 290 pounds load per shelf.

Design:
The shelves will be .75" x 11.5" x 48" hickory boards. Under the back for support will be a .5" x 1" x 48" (w x h x l) board. The sides will use standard metal shelf braces. I wish to drill two 3/8 inch holes the full length of the shelves, one in the middle and one an inch back from the front and insert 3/8" diameter stainless steel rods for further bracing.

On Wednesday, May 20, 2020 at 3:33:54 PM UTC-7, wrote:
Will this prevent any sagging at least for 10 years, if not 20+?

Basic idea.
I am building a bookcase primarily of hickory ...
Design:
The shelves will be .75" x 11.5" x 48" hickory boards. Under the back for support will be a .5" x 1" x 48" (w x h x l) board. The sides will use standard metal shelf braces. I wish to drill two 3/8 inch holes the full length of the shelves, one in the middle and one an inch back from the front and insert 3/8" diameter stainless steel rods for further bracing.

Waste of steel. If you simplly insert a spacer board midshelf that runs from
the top of shelf N to the bottom of shelf N+1, it'll take the center-of-shelf stress
down to the base (and it won't rust). Even cheap wood would work, you can stain
it black so the hickory shows to best advantage.

Steel rods horizontally are floppier than wood, won't be much of a brace. The
use of a steel C section at the back of each shelf might be better (it's the metal
at top edge in compression, and bottom edge in tension, that makes rods
less effective than C sections or the old I-beams.)

If there's a plywood back on the unit, drill for a few pegs to shift the sag stress to that.

Or, you could make two 24" shelves from the 48" boards.
If you must perforate the shelves, a wood dowel or two will keep those
spacers in their place.

[taliaegh] wrote in message
...

Will this prevent any sagging at least for 10 years, if not 20+?

Basic idea.
I am building a bookcase primarily of hickory for my reference library. The
library consists of the Oxford English Dictionary, Great Books of Western
Civilization, various books on programming languages, ...

Calculations of load.
Many of the shelves will be loaded with books for full 4' length and books
of 12.5 inches tall by 10 inches wide. That gives a total volume of 6000
cubic inches or 98322.384 cubic centimeters. Based on the specific
gravity of paper of 1.2 grams/cubic centimeter, that yields a load of just
over 260 pounds. Allowing for 10% safety margin, that is about 290 pounds
load per shelf.

Design:
The shelves will be .75" x 11.5" x 48" hickory boards. Under the back for
support will be a .5" x 1" x 48" (w x h x l) board. The sides will use
standard metal shelf braces. I wish to drill two 3/8 inch holes the full
length of the shelves, one in the middle and one an inch back from the front
and insert 3/8" diameter stainless steel rods for further bracing.

================================================== ===========

Horizontal 3/8" rods won't prevent sagging for 10 seconds, even if you could
magically drill 48" deep without breaking out through the face of the shelf.
I just went down to the secret laboratory, clamped one end of a 3/8" x 3'
steel rod in the milling machine vise and deflected the other end 4" with my
little finger. All types of steel deflect about the same distance under the
same load, regardless of their hardness.

What you described works in concrete bridges because the steel rods are in
the bottom edges of beams of considerable height, and they are tightened to
resist a pure tension load, not bending.

My heavily loaded wall of book shelves are of 1-1/16" thick x 9" wide red
oak with supports 30" apart, and no sag is visible when sighting down them.
I sawed the logs into 1-1/2" planks hoping for 5/4" finished thickness, but
they cupped during seasoning and 1-1/16" is where the planer cleaned up both
sides of most of them.

https://www.woodbin.com/calcs/sagulator/

The simple fix is to insert upright supports in the middle of the spans.
Mine are simply a friction fit and none have shifted.

What braces the bookcase against tipping sideways?

On Wed, 20 May 2020 15:33:51 -0700 (PDT), wrote:

Will this prevent any sagging at least for 10 years, if not 20+?

Basic idea.
I am building a bookcase primarily of hickory for my reference library. The library consists of the Oxford English Dictionary, Great Books of Western Civilization, various books on programming languages, ...

Calculations of load.
Many of the shelves will be loaded with books for full 4' length and books of 12.5 inches tall by 10 inches wide. That gives a total volume of 6000 cubic inches or 98322.384 cubic centimeters. Based on the specific gravity of paper of 1.2 grams/cubic centimeter, that yields a load of just over 260 pounds. Allowing for 10% safety margin, that is about 290 pounds load per shelf.

Design:
The shelves will be .75" x 11.5" x 48" hickory boards. Under the back for support will be a .5" x 1" x 48" (w x h x l) board. The sides will use standard metal shelf braces. I wish to drill two 3/8 inch holes the full length of the shelves, one in the middle and one an inch back from the front and insert 3/8" diameter stainless steel rods for further bracing.

You may have some problems with drilling 3/8" holes 4 feet deep and
round rod is not particularly stiff. I wonder whether a different
solution might not be simpler and, perhaps, stronger. For example 3/4"
angle inlayed on the front edge of the shelves. Or even 3/4 inch flat
stock fastened to the front edge with multiple fasteners.
One assumes multiple fasteners along the rear of each shelf to the 1"
rear of the case.
--
cheers,

John B.

[taliaegh] wrote in message
...

Under the back for support will be a .5" x 1" x 48" (w x h x l) board.

================================================== ==========

Your posting suggests that you have no hands-on experience with the
structural limitations of wood or metal. We all started there. The good
suggestion of doweling intermediate vertical supports, for example, requires
more than beginner skill at woodworking to make the holes align, and
"standard metal shelf braces" includes many types that would be inadequate
for your design load.

Are you planning to build this yourself?

On Thu, 21 May 2020 08:53:47 +0700, John B.
wrote:

On Wed, 20 May 2020 15:33:51 -0700 (PDT), wrote:

Will this prevent any sagging at least for 10 years, if not 20+?

Basic idea.
I am building a bookcase primarily of hickory for my reference library. The library consists of the Oxford English Dictionary, Great Books of Western Civilization, various books on programming languages, ...

Calculations of load.
Many of the shelves will be loaded with books for full 4' length and books of 12.5 inches tall by 10 inches wide. That gives a total volume of 6000 cubic inches or 98322.384 cubic centimeters. Based on the specific gravity of paper of 1.2 grams/cubic centimeter, that yields a load of just over 260 pounds. Allowing for 10% safety margin, that is about 290 pounds load per shelf.

Design:
The shelves will be .75" x 11.5" x 48" hickory boards. Under the back for support will be a .5" x 1" x 48" (w x h x l) board. The sides will use standard metal shelf braces. I wish to drill two 3/8 inch holes the full length of the shelves, one in the middle and one an inch back from the front and insert 3/8" diameter stainless steel rods for further bracing.

You may have some problems with drilling 3/8" holes 4 feet deep and
round rod is not particularly stiff. I wonder whether a different
solution might not be simpler and, perhaps, stronger. For example 3/4"
angle inlayed on the front edge of the shelves. Or even 3/4 inch flat
stock fastened to the front edge with multiple fasteners.
One assumes multiple fasteners along the rear of each shelf to the 1"
rear of the case.
It's not so much that the rods are stiff - if you use BOLTS and
tension them against the shelf you mightbe able to significantly
increase the bending strength of the shelf - but "gun drilling" a 4
foot shelf is going to be something of a problem, me-thinks.

On 21/5/20 8:33 am, wrote:
Will this prevent any sagging at least for 10 years, if not 20+?

Basic idea.
I am building a bookcase primarily of hickory for my reference library. The library consists of the Oxford English Dictionary, Great Books of Western Civilization, various books on programming languages, ...

Calculations of load.
Many of the shelves will be loaded with books for full 4' length and books of 12.5 inches tall by 10 inches wide. That gives a total volume of 6000 cubic inches or 98322.384 cubic centimeters. Based on the specific gravity of paper of 1.2 grams/cubic centimeter, that yields a load of just over 260 pounds. Allowing for 10% safety margin, that is about 290 pounds load per shelf.

Design:
The shelves will be .75" x 11.5" x 48" hickory boards. Under the back for support will be a .5" x 1" x 48" (w x h x l) board. The sides will use standard metal shelf braces. I wish to drill two 3/8 inch holes the full length of the shelves, one in the middle and one an inch back from the front and insert 3/8" diameter stainless steel rods for further bracing.



A 3/8" hole through the middle (if you can even get it in the middle) of
a 3/4" piece of timber is going to leave only 3/16" above and below.

No matter how strong and stiff the steel is, the timber shelf will break
away from the steel as soon as you load it up.

CH

"Clare Snyder" wrote in message
...

It's not so much that the rods are stiff - if you use BOLTS and
tension them against the shelf you mightbe able to significantly
increase the bending strength of the shelf - but "gun drilling" a 4
foot shelf is going to be something of a problem, me-thinks.
==================================================

The metal rods under the steps of a wooden step ladder are good examples of
this.

On 5/20/2020 8:55 PM, Jim Wilkins wrote:
....

https://www.woodbin.com/calcs/sagulator/
...

Neat!

"Bob Engelhardt" wrote in message ...

On 5/20/2020 8:55 PM, Jim Wilkins wrote:
....

https://www.woodbin.com/calcs/sagulator/
...

Neat!
==================
"This calculator can also be used to measure beam deflection. Because beams
are typically positioned on edge, use €œthickness€� to represent beam depth
and €œdepth€� to represent the thickness of the beam. The shelf span parameter
represents the beam span."

on Wed, 20 May 2020 15:33:51 -0700 (PDT) typed in
rec.crafts.metalworking the following:
Will this prevent any sagging at least for 10 years, if not 20+?

Basic idea.
I am building a bookcase primarily of hickory for my reference library. The library consists of the Oxford English Dictionary, Great Books of Western Civilization, various books on programming languages, ...

Calculations of load.
Many of the shelves will be loaded with books for full 4' length and books of 12.5 inches tall by 10 inches wide. That gives a total volume of 6000 cubic inches or 98322.384 cubic centimeters. Based on the specific gravity of paper of 1.2 grams/cubic centimeter, that yields a load of just over 260 pounds. Allowing for 10% safety margin, that is about 290 pounds load per shelf.

Design:
The shelves will be .75" x 11.5" x 48" hickory boards. Under the back for support will be a .5" x 1" x 48" (w x h x l) board. The sides will use standard metal shelf braces. I wish to drill two 3/8 inch holes the full length of the shelves, one in the middle and one an inch back from the front and insert 3/8" diameter stainless steel rods for further bracing.

Steel rods will bend.

If you don't want the shelves to sag: first option (IMO)would be
center supports. Don't have to be thick, just transfer the weight
from the top to the floor.

Other option I would suggest is to either channel or angle stock
attached to the front. You could even make the channel OD the same as
the board thickness and rabbit the edge. Much more rigid than a rod.
Also, you don't have the problem of trying to drill 48" deep six
to eight times, without the bit ever wandering out the side. Not
sure if they make ship augers (the sort which has no pilot screw on
the tip) that length, but you can weld a 4 foot rod on the end..

OT3H,I'm not sure that hickory will need reinforcing. But if
there is any bow in the boards, make that the "up side" so that any
sagging will flatten the shelf.
--
pyotr filipivich
"With Age comes Wisdom. Although far too often, Age travels alone."

Clifford Heath on Thu, 21 May 2020 14:07:41 +1000
typed in rec.crafts.metalworking the following:
On 21/5/20 8:33 am, wrote:
Will this prevent any sagging at least for 10 years, if not 20+?
Basic idea.
I am building a bookcase primarily of hickory for my reference library. The library consists of the Oxford English Dictionary, Great Books of Western Civilization, various books on programming languages,
Calculations of load.
Many of the shelves will be loaded with books for full 4' length and books of 12.5 inches tall by 10 inches wide. That gives a total volume of 6000 cubic inches or 98322.384 cubic centimeters. Based on the specific gravity of paper of 1.2 grams/cubic centimeter, that yields a load of just over 260 pounds. Allowing for 10% safety margin, that is about 290 pounds load per shelf.
Design:
The shelves will be .75" x 11.5" x 48" hickory boards. Under the back for support will be a .5" x 1" x 48" (w x h x l) board. The sides will use standard metal shelf braces. I wish to drill two 3/8 inch holes the full length of the shelves, one in the middle and one an inch back from the front and insert 3/8" diameter stainless steel rods for further bracing.



A 3/8" hole through the middle (if you can even get it in the middle) of
a 3/4" piece of timber is going to leave only 3/16" above and below.

And there's the critical issue.

No matter how strong and stiff the steel is, the timber shelf will break
away from the steel as soon as you load it up.

IMHO, I'd go with adding a center divider on all shelves, to
transfer load to the floor. Doesn't have to be a thick piece, could
be 1/4 ".
Or you could get some tall books from a thrift sore, and wrap the
cover around a board, so that you don't have a visible support.

CH
--
pyotr filipivich
"With Age comes Wisdom. Although far too often, Age travels alone."

"Jim Wilkins" on Wed, 20 May 2020 20:55:16
-0400 typed in rec.crafts.metalworking the following:

https://www.woodbin.com/calcs/sagulator/

Neat. Now to find out what the shelves I have are made of, so I
can retro calc their deflection.

{I have some Ikea Billy book cases. The wider shelves have sagged
visibly over the last fifteen years, but I can't just flip the shelves
so that they flatten. They work, and I've other things higher on the
priority list. Like fining space for the rest of the books.}

The simple fix is to insert upright supports in the middle of the spans.
Mine are simply a friction fit and none have shifted.

What braces the bookcase against tipping sideways?

That backboard. In the last move, the press board backs fell out
of mine, but that's okay, the shelves are from wall to all, so there's
no room for them to lean. Unless the whole place is out of kilter, in
which case, those cases will fit in just fine.
--
pyotr filipivich
"With Age comes Wisdom. Although far too often, Age travels alone."

On 5/21/2020 12:30 PM, pyotr filipivich wrote:
Neat. Now to find out what the shelves I have are made of, so I
can retro calc their deflection.
...

There is particle board on the list, but there's a bunch of varieties
(who knew).

On Thursday, May 21, 2020 at 9:31:09 AM UTC-7, pyotr filipivich wrote:
"Jim Wilkins" on Wed, 20 May 2020 20:55:16
-0400 typed in rec.crafts.metalworking the following:

https://www.woodbin.com/calcs/sagulator/

Neat. Now to find out what the shelves I have are made of, so I
can retro calc their deflection.

{I have some Ikea Billy book cases. The wider shelves have sagged
visibly over the last fifteen years, but I can't just flip the shelves
so that they flatten.

I think you'll find the sagulator only tells Young's modulus sag for flakeboard, it
ignores the long-term moisture induced bowing that you see. That
depends entirely on the glue used (so it's unpredictable). Even the
cheapest white woods are better shelving.

Bob Engelhardt on Thu, 21 May 2020
18:02:12 -0400 typed in rec.crafts.metalworking the following:
On 5/21/2020 12:30 PM, pyotr filipivich wrote:
Neat. Now to find out what the shelves I have are made of, so I
can retro calc their deflection.
...

There is particle board on the list, but there's a bunch of varieties
(who knew).

Its one of those "Now that you mention it, it is so obvious."
items.
--
pyotr filipivich
"With Age comes Wisdom. Although far too often, Age travels alone."

whit3rd on Fri, 22 May 2020 11:53:51 -0700 (PDT)
typed in rec.crafts.metalworking the following:
On Thursday, May 21, 2020 at 9:31:09 AM UTC-7, pyotr filipivich wrote:
"Jim Wilkins" on Wed, 20 May 2020 20:55:16
-0400 typed in rec.crafts.metalworking the following:

https://www.woodbin.com/calcs/sagulator/

Neat. Now to find out what the shelves I have are made of, so I
can retro calc their deflection.

{I have some Ikea Billy book cases. The wider shelves have sagged
visibly over the last fifteen years, but I can't just flip the shelves
so that they flatten.

I think you'll find the sagulator only tells Young's modulus sag for flakeboard, it
ignores the long-term moisture induced bowing that you see. That
depends entirely on the glue used (so it's unpredictable). Even the
cheapest white woods are better shelving.

Yep. OTOH, It came in a box, I could put it together without
power tools ... "it worked".
And that is the basic question: how much time and effort is it
worth to DIY, vs buy one in an box vs buy one already made?
--
pyotr filipivich
"With Age comes Wisdom. Although far too often, Age travels alone."

"pyotr filipivich" wrote in message
...

Yep. OTOH, It came in a box, I could put it together without
power tools ... "it worked".
And that is the basic question: how much time and effort is it
worth to DIY, vs buy one in an box vs buy one already made?
--
pyotr filipivich

================================================

For me the value of the product and the time and effort of finishing it
drive that decision, since I have the woodworking machinery. All the
Christmas present custom furniture that passes around the family is
hand-made. I bought a particle-board stereo cabinet but built a wall of
bookshelves from scratch (felled the tree...) and a light table for drafting
circuit boards, just before CAD made it obsolete.

Then I put a heavy HP spectrum analyzer atop the stereo cabinet and barely
caught it when the cabinet collapsed.

"Jim Wilkins" on Fri, 22 May 2020 17:56:03
-0400 typed in rec.crafts.metalworking the following:

For me the value of the product and the time and effort of finishing it
drive that decision, since I have the woodworking machinery. All the
Christmas present custom furniture that passes around the family is
hand-made. I bought a particle-board stereo cabinet but built a wall of
bookshelves from scratch (felled the tree...) and a light table for drafting
circuit boards, just before CAD made it obsolete.

Then I put a heavy HP spectrum analyzer atop the stereo cabinet and barely
caught it when the cabinet collapsed.

When I have the time. I have a couple sets of shelves (One for my
clothes, the other to hold "stuff" in the shop), knocked out of the
boards from a shipping crate. no real attempt to finish either one.
"they work."
But the things I'm intending for the wife, those will get more
care in the fit and finishing.


--
pyotr filipivich
"With Age comes Wisdom. Although far too often, Age travels alone."

"pyotr filipivich" wrote in message
...

When I have the time. I have a couple sets of shelves (One for my
clothes, the other to hold "stuff" in the shop), knocked out of the
boards from a shipping crate. no real attempt to finish either one.
"they work."
But the things I'm intending for the wife, those will get more
care in the fit and finishing.
pyotr filipivich

=======================================

I discovered that the columns of a set of plastic shelves I bought have the
same 1.66" OD as 1-1/4" plastic electrical conduit, so I used some to raise
the lowest shelf off the floor.

"Jim Wilkins" on Sat, 23 May 2020 13:01:47
-0400 typed in rec.crafts.metalworking the following:
"pyotr filipivich" wrote in message
.. .

When I have the time. I have a couple sets of shelves (One for my
clothes, the other to hold "stuff" in the shop), knocked out of the
boards from a shipping crate. no real attempt to finish either one.
"they work."
But the things I'm intending for the wife, those will get more
care in the fit and finishing.
pyotr filipivich

=======================================

I discovered that the columns of a set of plastic shelves I bought have the
same 1.66" OD as 1-1/4" plastic electrical conduit, so I used some to raise
the lowest shelf off the floor.

Neat.

I had two sets of the ABS shelves. Mounted them on a piece of OSB
with wheels. It did allow me to pull the shelves out where I could
get at them. But the OSB didn't hold the weight and sagged in the
middle. Not good - on to the next Good Idea!
--
pyotr filipivich
"With Age comes Wisdom. Although far too often, Age travels alone."

On Sat, 23 May 2020 14:34:14 -0700, pyotr filipivich
wrote:

"Jim Wilkins" on Sat, 23 May 2020 13:01:47
-0400 typed in rec.crafts.metalworking the following:
"pyotr filipivich" wrote in message
. ..

When I have the time. I have a couple sets of shelves (One for my
clothes, the other to hold "stuff" in the shop), knocked out of the
boards from a shipping crate. no real attempt to finish either one.
"they work."
But the things I'm intending for the wife, those will get more
care in the fit and finishing.
pyotr filipivich

=======================================

I discovered that the columns of a set of plastic shelves I bought have the
same 1.66" OD as 1-1/4" plastic electrical conduit, so I used some to raise
the lowest shelf off the floor.

Neat.

I had two sets of the ABS shelves. Mounted them on a piece of OSB
with wheels. It did allow me to pull the shelves out where I could
get at them. But the OSB didn't hold the weight and sagged in the
middle. Not good - on to the next Good Idea!

The only..only way to build heavy book shelves is using 3/4" plywood.
You can use 3/4" fir or pine planks..but plywood is cheaper. And put a
vertical support every 3'. You can alternate the verticals or you can
slot (or dado) them and slide the shelves into the slots.

Ive got about 6000 books...Ive had to build a **** ton of 8' tall book
cases.

Gunner
__

"Journalists are extremely rare and shouldn’t be harmed, but propagandists are everywhere and should be hunted for sport"

Yeah..with no bag limit.




--
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