Would this be secure?

[AndyT]

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?

Well, that's where you could use a sliding dovetail at top and bottom which is what I thought you meant.

(Actually the top piece would be better as a lap dovetail, fitted in from above, - sliding dovetails would be working on a tiny bit of end grain at the top.)

I'm still not clear if you need this piece to be easy to take apart to move out of the room it will be in. To my mind, the "normal" construction would be to have a big box (ie full length outer uprights and horizontals) holding two inside full-height verticals, with central shelves fixed and intermediate shelves on pegs or similar. Each of the parts is just a piece of wood and will go up the stairs easily so you build it in the room. You get the best rigidity if you make it a jointed and glued structure, but you can get almost as much strength using a mixture of dry dowels and screws, like flatpack but in nicer wood and to the exact dimensions you need.

 

[Richard T]

Charlie - they are dry fit. If I did another I would definitely use tapered, sliding dovetails. Also dry.

Now they are in situ' here, they run from one wall to the other, I extended them so that they all fit tight the length of the room - about 18' long with seven uprights and twelve sets of seven shelves, so not really relevant for your purpose I'm afraid.

 

[Charlie Woody]

OK thanks very much guys.

Due to the length of the boards I don't think I have the skills to cut the lapped dovetails. So I think that I will use sliding dovetails on the middle unit second shelf from the top and the bottom one. The rest can sit on shelf pins.

I would prefer to make as much of it as possible in the workshop so that if there are any problems then I can resolve them without the pressure of someone looking over my shoulder!!!

 

[Charlie Woody]

Well guys I have been thinking about this whilst on hols last week and think I will proceed as follows:

1. Left & Right Units: Dovetail bottom & second from top shelves. Rest on pins - with 3 hole positions (except from top shelf) so they can be moved up / down if required.
2. Middle Unit: Dry biscuit top shelf and second from bottom shelf. Insert screws from left & right units into these on site (pre drilled in workshop). The shelves from the left & right unit will hopefully conceal these screws.
3. Use Eric's concealed feet idea to allow for any necessary adjustment for uneven floor and to aid sliding the three units together.
4. Use a mending plate on the back of the verticals to fix to the wall. As I will be using the concealed feet I am thinking of hacksawing between the top two screw holes to create a vertical slot to allow for vertical adjustment of the units. I have been looking but cannot find any mending plates or similar with a slot rather than a screw hole.

A sketchup is attached which shows the mending plates without screw holes (don't know how to draw them) and without the adjusting feet ..... well had to leave something to your imagination :lol:

Now I need to work out the best way of cutting the sliding dovetails. I have a woodrat but I'm not sure that I could use it for the 2m + verticals so will make a trawl of you tube to see if there is anything there.

 

[Charlie Woody]

Just being looking at Wealden's site for a dovetail cutter to make the sliding dovetails for this bookcase. I think it would be easier to use my 1/4 inch router handheld with some sort housing jig.

So which of these cutters would you use please? http://www.wealdentool.com/acatalog/Onl ... l_122.html