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Old 12-01-11, 11:21 AM   #1
AEO
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anyone with some woodworking advice?

I designed this bookcase to be compact and moveable. Basically, it's like a trunk on its side. The books will only be accessible when the door is open. I did it this way to keep dust and moisture out and also allow the casters to sit further out when closed. One side will be anchored to the wall, because I don't need to roll it around yet.

I was thinking of using 8 to 12 or so 1-5/8' tall casters per piece (16 or 24 total), but I'm not so sure of what sort of hinges or locking latches to use. The casters sit about 1/4 higher than the base of the frame, so that I can slide in some wedges on the anchored side to keep it from moving. I might just forgo locking latches and use some ratcheting straps if it needs to be moved. I'm also unsure if there are any design flaws, but I guess my main concern is how well the 6" deep frame will hold up to flexing.

Most of this will be cut from 12' x 97' x 5/8' particle veneer boards (white) and MDF boards (brown) of the same size. I forgot what the thin backboards were called. The shelves will be screwed in on the sides. I'm not entirely sure how to affix the center support columns. The base will be double thick, so that it is more stiff and so that the weight is distributed more evenly onto the casters.

I guess it would be easier to fix the center columns and base if I used MDF all around, because I would be able to glue it more effectively.





edit:

alternative 1: use tracks to slide front shelves, while rear remains fixed.
alternative 2: use 12' deep shelf and skip gimmicky doors or tracks, but it will still be on casters.

shelf length is easier to cut, for me, if it's half of 72' or 97'.
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Old 12-01-11, 11:40 AM   #2
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Got Wood?
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Old 12-01-11, 11:43 AM   #3
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PM Wordbiker! Dude is better with wood than he is with words. Really talented craftsman. He did a foldway desk recently that is a work of art.
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Old 12-01-11, 11:49 AM   #4
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Measure twice, cut once. I would look at using a 3/4 Baltic Birch plywood, it's stronger, tougher and wont warp/flex like that MDF s**t. Plus if you have access to a table saw you can dado it together. Pre-drill all the screws and don't be cheap with the glue.
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Old 12-01-11, 12:31 PM   #5
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I wouldn't rely on the MDF to take the point loading of the castors. Couple that with the horizontal forces that will be applied with the rolling and I just don't see that particular point of your base holding up well.
You'll also need to consider the loading on your hinges. Your Dead Load of books alone (per shelf side) could run in the neighborhood of 264 pounds (assuming 22lbs/cuft). Add in the weight of the the shelf and you have a pretty heavy system. Standard hinges aren't that heavy duty.

So, some quick hack calculations:

264 lbs / 8 castors = 33 lbs per castor. Given a point load and an assumed 3x3 plate on the castor you'll have something in the neighborhood of a 3.67psi vertical load. (engineers step in and stop me at any point. I am but a lowly arch intern.)

264 lbs / 12 castors = 22lbs per castor = 2.44 psi vertical loading.

You'll at least need heavy duty hinges depending on the number of hinges you plan to use. Product literature on the hinges you look at should tell you their loading/quantity capabilities. The loads on the castors might not be as bad as I thought at the start of this post.
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Old 12-01-11, 12:36 PM   #6
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Quote:
Originally Posted by AEO View Post
I designed this bookcase to be compact and moveable. Basically, it's like a trunk on its side. The books will only be accessible when the door is open. I did it this way to keep dust and moisture out and also allow the casters to sit further out when closed. One side will be anchored to the wall, because I don't need to roll it around yet.
If I'm understanding correctly, the right-most section will be attached to the wall and the other 3 sections will be places on casters & hinged together? If so, there is one fundamental flaw here... you are assuming that your floor is flat. I've built a few cabinets and the 1st thing you do when you install is build a base that is perfectly level (base moulding covers this). If you don't, the sides of the cabinet will not sit flush with each other (a particular issue for you since they will be hinged together & the hinges will bind or break). Your idea can still work if you ensure flatness wherever your bookshelves will roll (flat to the wall mounted shelf).

With smaller pieces you can get away without having to level... however, you've got 6'x12' of shelving that will be supporting a lot of weight. Also, if earthquakes are even the slightest possibility then those casters (even locking casters or feet) will slide all over the place when there is a tremor.
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Old 12-01-11, 12:41 PM   #7
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An alternative for high density shelving may be a rolling rack shelf similar to this : http://www.rackline.com/products/monotrak.php
A friend of mine was able to pick up one of these used from a law firm for <$500.
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Old 12-01-11, 12:53 PM   #8
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You could carve it out of a tree that you grow in place. Will take a bit of time, but it will be solid.
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Phobias are for irrational fears. Fear of junk ripping badgers is perfectly rational. Those things are nasty.
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Old 12-01-11, 01:04 PM   #9
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Btw, my figures don't account for the fact that you have one pinned side. it was just assuming all loading could go straight down.
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Old 12-01-11, 01:15 PM   #10
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Hardwood, dowel joints, and heavy duty casters. With the appropriate hardwood frame 4 casters on each should he enough. Build the frame to support the weight. Not use flimsy mdf and shore it with casters. Pm if you need help. Wood is my winter thing. And if a sawmill is near you can buy white oak for less that no. 2 pine at the borg.
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Old 12-01-11, 01:16 PM   #11
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Originally Posted by 20grit View Post
I wouldn't rely on the MDF to take the point loading of the castors. Couple that with the horizontal forces that will be applied with the rolling and I just don't see that particular point of your base holding up well.
You'll also need to consider the loading on your hinges. Your Dead Load of books alone (per shelf side) could run in the neighborhood of 264 pounds (assuming 22lbs/cuft). Add in the weight of the the shelf and you have a pretty heavy system. Standard hinges aren't that heavy duty.

So, some quick hack calculations:

264 lbs / 8 castors = 33 lbs per castor. Given a point load and an assumed 3x3 plate on the castor you'll have something in the neighborhood of a 3.67psi vertical load. (engineers step in and stop me at any point. I am but a lowly arch intern.)

264 lbs / 12 castors = 22lbs per castor = 2.44 psi vertical loading.

You'll at least need heavy duty hinges depending on the number of hinges you plan to use. Product literature on the hinges you look at should tell you their loading/quantity capabilities. The loads on the castors might not be as bad as I thought at the start of this post.
I think the castors were rated for at least 40lbs each. They look like 60lbs. models, however. They have 4 hole mounts and use ball bearings for the swivel
I was thinking of using 6 to 8 door hinges

Quote:
Originally Posted by Greg_R View Post
If I'm understanding correctly, the right-most section will be attached to the wall and the other 3 sections will be places on casters & hinged together? If so, there is one fundamental flaw here... you are assuming that your floor is flat. I've built a few cabinets and the 1st thing you do when you install is build a base that is perfectly level (base moulding covers this). If you don't, the sides of the cabinet will not sit flush with each other (a particular issue for you since they will be hinged together & the hinges will bind or break). Your idea can still work if you ensure flatness wherever your bookshelves will roll (flat to the wall mounted shelf).

With smaller pieces you can get away without having to level... however, you've got 6'x12' of shelving that will be supporting a lot of weight. Also, if earthquakes are even the slightest possibility then those casters (even locking casters or feet) will slide all over the place when there is a tremor.
It's actually 2 sets of folding shelves, so 2 are attached to the wall and 2 are swinging.

good point about floor flatness. That didn't really occur to me.
The alternatives are a sliding shelf that runs on tracks, but I'm not sure how well door hardware would work.
or
skip the gimmicks, and make a 12" (or 16") deep, movable shelf by not splitting the boards in half. The only problem is stability whem moving it around and keeping it from swaying down the width. I guess I could run the support column width wise, but that would could leave quite a bit of scraps.

I can even go with 36' shelves, which would make the frame less prone to twisting.
There's really only a few sizes of boards my area stocks.

Quote:
Originally Posted by Bomccorkle View Post
Hardwood, dowel joints, and heavy duty casters. With the appropriate hardwood frame 4 casters on each should he enough. Build the frame to support the weight. Not use flimsy mdf and shore it with casters. Pm if you need help. Wood is my winter thing. And if a sawmill is near you can buy white oak for less that no. 2 pine at the borg.
I'm only giving it more casters than necessary, because this will be on carpet and there's a lot of cat hair to deal with.
unfortunately, the best source for wood I have is home depot warehouse or rona, which is right next to the rail yard.
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Last edited by AEO; 12-01-11 at 01:29 PM.
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Old 12-01-11, 01:25 PM   #12
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Quote:
Originally Posted by jsharr View Post
You could carve it out of a tree that you grow in place. Will take a bit of time, but it will be solid.
I do have a maple out in the front...

Quote:
Originally Posted by Greg_R View Post
An alternative for high density shelving may be a rolling rack shelf similar to this : http://www.rackline.com/products/monotrak.php
A friend of mine was able to pick up one of these used from a law firm for <$500.
I've tried to get some library steel shelving before. The price was right, but there was no way I could haul those shelves and pillars with the man power and hauling capacity I had.
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Old 12-01-11, 03:23 PM   #13
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Quote:
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I'm only giving it more casters than necessary, because this will be on carpet and there's a lot of cat hair to deal with.
http://www.tente.us/US/cat0/an3917_f...e_casters.html
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Old 12-01-11, 03:44 PM   #14
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I was thinking of using 6 to 8 door hinges
Check your costs. If you're going to run 6-8 Door hinges in something 6' tall, you might just want to consider using a Piano hinge instead. Just check the ratings.
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Old 12-01-11, 06:54 PM   #15
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Check your costs. If you're going to run 6-8 Door hinges in something 6' tall, you might just want to consider using a Piano hinge instead. Just check the ratings.
This is good advice. A piano hinge will mount on the surface, door hinges will have to be mortised in. Also, door hinge screws are longer than 3/4" and will protrude unless replaced with shorter screws. Piano hinges install with many smaller screws.
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Originally Posted by overthehillmedi View Post
Measure twice, cut once. I would look at using a 3/4 Baltic Birch plywood, it's stronger, tougher and wont warp/flex like that MDF s**t. Plus if you have access to a table saw you can dado it together. Pre-drill all the screws and don't be cheap with the glue.
So is this, though any finish grade plywood in the species of your preference will be better than Melamine or MDF and require less tooling and time than solid woods. MDF has no grain structure and is very poor at supporting dead loads like books. Without some sort of edging reinforcement, your shelves will sag or worse. A dado is a good idea, even if just 1/4" depth as it supports the shelf from the bottom. Screws or nails only have the material above them for support. You just can't depend on glued joints alone with a piece that moves.

I'll also add that having built many units like this, your main issue will be putting the support fasteners in as well as finding a large enough flat clamping surface. If you're doing this project in a provisional shop, I'd suggest looking into a pocket screw jig. While I prefer the clean look of more traditional joinery methods, there's no arguing the speed and ease (as well as a minimal tool investment) of pocket screws. They draw the joints together nicely saving a lot of clamping and alignment issues. You'll have to plan your piece accordingly so they don't show, but Kreg (the largest pocket screw jig manufacturer) even makes filler plugs for certain materials.

If you hired me to build this for you, I would go with a face frame construction tied through the middle with a fixed shelf and add adjustable shelf pin drillings for versatility. Each shelf would be edged front and rear for strength (losing you a little space but insuring against crashes in the night) and about 9-10" depth. Only very odd books are deeper than that, and if you need that depth, only the main fixed section would need it, the rest could be made shallower to save redundant weight and stress on the casters and hinges.

Final note: this will be much heavier than you anticipate, even empty, but especially full of books. Make it fixed if possible.

Edit: I see a problem with your design. Plywood only comes in 48" widths (standard) or 49" (industrial). Unless you want to waste material or have exposed butt joints, make the width 48" or less.
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Old 12-02-11, 01:37 AM   #16
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okay, thank you all for your help

I will redesign this again from scratch.
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Old 12-02-11, 01:47 AM   #17
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How about a metal frame with wood panels attached?
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