Would this be secure?

[Charlie Woody]

I am building a large bookcase - very basic design, see Sketchup below - that has to go up a long flight of stairs.

My idea is to biscuit joint the upright supports to the underside of the shelves and glue these in place, but, dry fit the biscuit joints into the top of the shelves. Apply finish. Dismantle the dry joints to take upstairs and then dry fit them again, so that if required at a future date the unit could be dismantled.

I am thinking of routing a shallow groove in the wall side of the uprights to screw some of http://www.screwfix.com/p/mending-plate ... f-10/16050 to the upright and the wall. These would go along the uprights just under the top and in the middle shelf. As I will be using oak, might need to use brass ones (if available).

I have three questions please:
1. Will leaving the dry biscuit joint be secure enough given the height of the unit > 2m?
2. Will the mending plates be enough to stop the unit toppling, given the dry biscuit joints, height and the fact it it to sit on existing carpet so levelling could be thrown out once loaded with books?
3. If the answer to 2 is yes, if I cannot find brass mending plates, if I apply finish to the grooves will this stop the plates staining the oak?

 

[Stormer1940]

I would be inclined to suggest that the shelving length is reduced to stop the shelves sagging under the weight of the books.

 

[Charlie Woody]

I would be inclined to suggest that the shelving length is reduced to stop the shelves sagging under the weight of the books.

I have checked this with the sagulator and the length is ok.

Do you have any ideas on the 3 questions I posed in the orignal post please

 

[Mr T]

Hi

Unless the room is very damp you probably don't need to worry about staining.

Not sure about the sagging when you load it with books and it sinks into the carpet. Could you not design it with a plinth at the bottom so the carpet can be cut. Unless of course you don't want to cut the carpet as you may be removing the case at some point

Chris

 

[Charlie Woody]

Hi Chris

Good news on the mending plates.

You are correct that I don't want to cut the carpet, hence the no plinth design.

Do you think the dry biscuit joints will be ok?

Thanks for your help.

 

[Richard T]

When I made ours, I jointed all the shelves into the uprights. Nothing fancy - just straight across mortises the width of the shelves (tight fits).
We did move it when SWMOM moved in here and found I had to number all the pieces, it was so snug a fit.

Hence no experience of glued - up biscuits ... I did it all by hand and it didn't take too long. Would be a whizz with a router I should think.

 

[AndyT]

1. Will leaving the dry biscuit joint be secure enough given the height of the unit > 2m?
2. Will the mending plates be enough to stop the unit toppling, given the dry biscuit joints, height and the fact it it to sit on existing carpet so levelling could be thrown out once loaded with books?
3. If the answer to 2 is yes, if I cannot find brass mending plates, if I apply finish to the grooves will this stop the plates staining the oak?

1. I think it would be steady enough, once loaded, not sure before. Does the customer already have a lot of books, enough to fill it up immediately?

2. Yes, but I'm struggling to visualise this. You wrote that they would go "along the uprights just under the top and in the middle shelf" - if you do that you won't be able to put all the screws in - you can screw them to the shelves, or to the wall, but not both.
Maybe you meant "across the uprights" so one screw would come forwards into the back edge of an upright and three screws would go into the wall. A bit odd and asymmetrical.
I'd use mirror plates in some corners, or even the Screwfix corner pieces http://www.screwfix.com/p/corner-plates-zinc-plated-83-x-83-x-0-9mm-pack-of-10/13954# - you can fix these onto the back, lean the bookcase in position and then drill and screw through into the wall. (Buy the right screws and plugs and you don't need to move anything - you can drill with the bookcase in position and keep it there.)

3. I don't think staining would be a big deal with galvanised plates; but brass or brass-plated mirror plates are easy to find.

That said, I do wonder about the appearance of the finished thing. It might look a shame to have bought nice 2m oak boards and then cut them into eight little pieces. Ordinary flat-pack bookcases would keep the uprights as single pieces which would be stronger and look better.

Another option would be to use biscuits as described, but make the unit as three vertical modules. Unless the stairs are really tiny (too small for people?) they would go up easily. Your design could be built up without any tools but I'm thinking something more like conventional flat-pack, where the perimeter pieces are dry dowelled (or biscuited) then screwed together with concealed screws.

 

[Chrispy]

The trouble with biscuits is that there is not really any front to back alignment so you may find that the shelves move about and wont stay flush, a few dowels would cure that though.

 

[Phil Pascoe]

I would ask the customer to check the sizes of the shelves - most of my shelves are wider and deeper than them, and still I have loads of books that don't fit them. Get the sizes in writing, at least then you won't get the blame when nothing fits on them.

 

[John Brown]

Watch out for weevils in those dry biscuits.

 

[Eric The Viking]

The major drawback with this approach is that the stability depends on your ability to cut very accurately.

If any of the verticals aren't cut parallel or identically sized, the thing will wobble. That's one good reason why bookcase carcases aren't usually done this way. Knock-down plates may help, but they will be fiddly to fit, will look unsightly (if there's no backing board) and aren't all that strong.

On the biscuits issue: They're a loose fit in the slots until glue (dampness) makes them swell. The swelling is intended to make them tight, and it's not a controlled thing. I think you'd find it really awkward to do it that way, as controlling where the glue goes and the amount the biscuits swell would be very tricky.

If you must do this, hardwood dowels with tapered ends on the outside would be far better (don't forget to groove the end you glue in!), or brass pins. I'm sure I've seen them around, but you can get 8mm brass bar easily enough, and smaller sizes. The last piece I had was 3m long, which ought to be plenty for the task. Once you cut to length with a hacksaw you can get a nice finished bevel end by spinning the pin in a pillar drill and finishing with a file followed by wet+dry paper, if necessary stuck to a block of wood.

Our floors are far from flat here, so pretty much every bit of bedroom furniture is either scribed to the slope (if it's IKEA's finest), or has invisible adjustable feet added to it. These are very easy to do in the workshop and cost pennies:

Use a 6mm coachbolt, the dome-headed sort with a square shank just before the thread starts. If it's taking lots of weight, step up to 8mm. The other half of the equation is a pronged-tee nut. This goes into the bottom of the piece, with a clearance hole behind for the "T" and the bolt. It's a good idea to fix it in with epoxy, especially if using into the edge of man made boards:

It's adjustable with a spanner from below, and is hidden by carpet (all you see is the wooden foot enclosing it, usually). If you want it completely invisible, you can make it top adjustable, by hacksawing a slot in the end of the coachbolt, but that only really works for strong lightweight carcases. I would do the spanner-adjust version for a bookcase, because of the weight. The single point of contact means things don't wobble at all, even though our floors are very dished.

For a bookcase, the pink-brown bit it's sitting in ought to be a vertical. You could cut a housing about 1" back from the front edge, making it spanner-adjustable from the side but invisible from the front. You could also embed a nut straight into the wood, but that won't bear as much weight as a t-nut.

I hope the drawing makes sense. sorry - you have to imagine the actual thread as I can't knock them out quickly in Corel!

 

[AndyT]

Eric that's a really ingenious adjustable foot! - worth a duplicate post in the jigs and tips, I think.
I have a box of coachbolts and a bag of t-nuts. Next time I make something floorstanding, I will be copying you!

 

[Charlie Woody]

When I made ours, I jointed all the shelves into the uprights. Nothing fancy - just straight across mortises the width of the shelves (tight fits).
We did move it when SWMOM moved in here and found I had to number all the pieces, it was so snug a fit.

Hence no experience of glued - up biscuits ... I did it all by hand and it didn't take too long. Would be a whizz with a router I should think.

Richard, did you use glue or were they a dry fit?

 

[Eric The Viking]

Eric that's a really ingenious adjustable foot! - worth a duplicate post in the jigs and tips, I think.
I have a box of coachbolts and a bag of t-nuts. Next time I make something floorstanding, I will be copying you!

I laugh when I see a lot of modern furniture designs in the magazines - they'd be useless in our place!

I lived in a modern flat once. Oh for flat, smooth concrete floors again!

E.

PS: forgot to say: I don't own a lathe, but if you drill carefully, the top-adjust sort work brilliantly inside bun feet. You can hide the foot almost completely, and there's only an 8mm hole inside the carcase (and a couple of screws either side of it!) to reveal how it levels.

 

[Charlie Woody]

1. I think it would be steady enough, once loaded, not sure before. Does the customer already have a lot of books, enough to fill it up immediately?

Yes

2. Yes, but I'm struggling to visualise this. You wrote that they would go "along the uprights just under the top and in the middle shelf" - if you do that you won't be able to put all the screws in - you can screw them to the shelves, or to the wall, but not both.
Maybe you meant "across the uprights" so one screw would come forwards into the back edge of an upright and three screws would go into the wall. A bit odd and asymmetrical.
I'd use mirror plates in some corners, or even the Screwfix corner pieces http://www.screwfix.com/p/corner-plates-zinc-plated-83-x-83-x-0-9mm-pack-of-10/13954# - you can fix these onto the back, lean the bookcase in position and then drill and screw through into the wall. (Buy the right screws and plugs and you don't need to move anything - you can drill with the bookcase in position and keep it there.)

See drawing attached ... does this clarify?

3. I don't think staining would be a big deal with galvanised plates; but brass or brass-plated mirror plates are easy to find.

That said, I do wonder about the appearance of the finished thing. It might look a shame to have bought nice 2m oak boards and then cut them into eight little pieces. Ordinary flat-pack bookcases would keep the uprights as single pieces which would be stronger and look better.

Another option would be to use biscuits as described, but make the unit as three vertical modules. Unless the stairs are really tiny (too small for people?) they would go up easily. Your design could be built up without any tools but I'm thinking something more like conventional flat-pack, where the perimeter pieces are dry dowelled (or biscuited) then screwed together with concealed screws.[/quote]

I thought about 3 seperate units but that means extra timber and where they join would show a line. But now you have caused me to think maybe I could try to use sliding dovetails so that I could leave the verticals as one piece then slide the shelves in on site. Downside to this is I think I might have to push them in from the front so the joint would be visible. Another problem is that I have never attempted sliding dovetails but might be a nice skill to learn.

 

[Charlie Woody]

The major drawback with this approach is that the stability depends on your ability to cut very accurately.

If any of the verticals aren't cut parallel or identically sized, the thing will wobble. That's one good reason why bookcase carcases aren't usually done this way. Knock-down plates may help, but they will be fiddly to fit, will look unsightly (if there's no backing board) and aren't all that strong.

On the biscuits issue: They're a loose fit in the slots until glue (dampness) makes them swell. The swelling is intended to make them tight, and it's not a controlled thing. I think you'd find it really awkward to do it that way, as controlling where the glue goes and the amount the biscuits swell would be very tricky.

If you must do this, hardwood dowels with tapered ends on the outside would be far better (don't forget to groove the end you glue in!), or brass pins. I'm sure I've seen them around, but you can get 8mm brass bar easily enough, and smaller sizes. The last piece I had was 3m long, which ought to be plenty for the task. Once you cut to length with a hacksaw you can get a nice finished bevel end by spinning the pin in a pillar drill and finishing with a file followed by wet+dry paper, if necessary stuck to a block of wood.

Suppose I could use Miller Dowels too?

Our floors are far from flat here, so pretty much every bit of bedroom furniture is either scribed to the slope (if it's IKEA's finest), or has invisible adjustable feet added to it. These are very easy to do in the workshop and cost pennies:

Use a 6mm coachbolt, the dome-headed sort with a square shank just before the thread starts. If it's taking lots of weight, step up to 8mm. The other half of the equation is a pronged-tee nut. This goes into the bottom of the piece, with a clearance hole behind for the "T" and the bolt. It's a good idea to fix it in with epoxy, especially if using into the edge of man made boards:

It's adjustable with a spanner from below, and is hidden by carpet (all you see is the wooden foot enclosing it, usually). If you want it completely invisible, you can make it top adjustable, by hacksawing a slot in the end of the coachbolt, but that only really works for strong lightweight carcases. I would do the spanner-adjust version for a bookcase, because of the weight. The single point of contact means things don't wobble at all, even though our floors are very dished.

For a bookcase, the pink-brown bit it's sitting in ought to be a vertical. You could cut a housing about 1" back from the front edge, making it spanner-adjustable from the side but invisible from the front. You could also embed a nut straight into the wood, but that won't bear as much weight as a t-nut.

I hope the drawing makes sense. sorry - you have to imagine the actual thread as I can't knock them out quickly in Corel!

Eric that is a great idea I guess the screw hole needs to be the length of the bolt

 

[Stormer1940]

I always try to dimension the length of the shelves between 500mm - 650mm.... Guess that's just my preference and no use of a Sagometer...

Plus I tend to use biscuits for locating rather than load bearing or strength.

 

[Eric The Viking]

Eric that is a great idea I guess the screw hole needs to be the length of the bolt

Yes, but you can always cut them down to suitable length with a hacksaw.

That said, having them a snug fit in a deep hole is probably a good idea, as it eliminates any vertical twisting force on the T-nut if the furniture gets pulled sideways when it's loaded. It's the way I've always done them too. The domed head means they slide pretty well on short-pile carpet (or threadbare round 'ere!).

I don't know about Miller dowels - they seem to divide opinion a bit. If it's out of sight, ordinary plain beech dowels (the fluted ones) ought to do fine I'd have thought, but I still think the 'horizontal' approach may give you problems if it's very tall.

It does add another issue too - You do need the positioning, so not only do you have to cut very precisely, you also have to position the dowels very exactly as well. I think you're making work for yourself this way, TBH.

E.

 

[AndyT]

I thought about 3 seperate units but that means extra timber and where they join would show a line. But now you have caused me to think maybe I could try to use sliding dovetails so that I could leave the verticals as one piece then slide the shelves in on site. Downside to this is I think I might have to push them in from the front so the joint would be visible. Another problem is that I have never attempted sliding dovetails but might be a nice skill to learn.

I think this would be better, but don't make it too complicated or you will never get it together, let alone get it apart!
No need for extra timber - the end units can be complete with uprights but the centre one is just a pile of shelves. (Some flat pack bookcases just give you one upright as a sort of extension unit, which is another option.)

I've used sliding dovetails on a grand total of three bookcases so far. One was small and ok. On a bigger one, I did a test assembly and it was so solid it never came apart again. (Mahogany, about eight inches deep, straight, dovetailed both sides. No need for glue!)

On the last one (documented hereI tapered the sliding dovetail so it stays loose most of the way and tightens up right at the end. This is not easy to do! You only really get one go at it, and glue makes the fit (and the slip) quite different, so aim for an easy sliding fit and you won't be looking for a bigger hammer like I was.

Also, don't do more than a pair of such joints - at the top and bottom - or else you won't get it assembled at all. The intermediate shelves can be held on studs, or magic wires, or indeed on biscuits glued on one side and dry into grooves on the other. There was a good thread on this topic recently.

 

[Charlie Woody]

No need for extra timber - the end units can be complete with uprights but the centre one is just a pile of shelves. (Some flat pack bookcases just give you one upright as a sort of extension unit, which is another option.)

Andy,
If I understand you correctly you are saying I should do the following:
1. Make and glue up the left hand section (as you look at my original sketchup), the make and glue up the right hand section.
2. Connect the left and right sections with shelves.

Don't I need some way of fixing the middle section of shelves to the left and right section or they may come apart? Or have I misunderstood?