• We invite you to join UKWorkshop.
    Members can turn off viewing Ads!

Torsion box alcove shelves

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

Alie Barnes

Established Member
Joined
16 May 2007
Messages
239
Reaction score
0
Location
Reading, Berkshire
Hello

I'm going to make some alcove shelves with battons on the back and sides and face the front, thinking of using 6mm veneered ply for the top and bottom. I am really not sure what timber to use though, i was thinking of using 44x44mm timber, in my brain this seems more than enough for the weight of books and bric a brac but the length is approx 1.8m so it makes me nervous that this might not be strong enough, it will have ribs between the back and front for rigidity, can i get peoples thoughts on if this would be strong enough and if not what wood would be a good alternative, i want to try to keep the shelves thickness to about 50mm or there abouts. Thanks, i have attached a picture i stole from the internet as my example.

Shelf1_zpskg6q9guz.jpg
 

TheTiddles

Established Member
Joined
14 Oct 2007
Messages
2,574
Reaction score
540
Location
Wiltshire
1.8m is a big span, however with a batten on the wall too, that should be fine. The thickness you are making them will make them look solid and not skinny too, even if thinner could still be stiff enough

Aidan
 

Alie Barnes

Established Member
Joined
16 May 2007
Messages
239
Reaction score
0
Location
Reading, Berkshire
1.8m is a big span, however with a batten on the wall too, that should be fine. The thickness you are making them will make them look solid and not skinny too, even if thinner could still be stiff enough

Aidan
I was thinking of doing double thickness across the front to prevent the front potentially sagging. this is why im not sure if 44x44mm is thick enough wood.
 

TheTiddles

Established Member
Joined
14 Oct 2007
Messages
2,574
Reaction score
540
Location
Wiltshire
6+44+44+6 would certainly be chunky, might look like more of a beam than a shelf though.

I suspect 44 with ply each side will be fine, but if you aren’t sure use ordinary cheap ply and make a single prototype which will also help you refine the look and process before using your nice material?

Aidan
 

Dee J

Established Member
Joined
24 Jan 2006
Messages
329
Reaction score
69
Location
West Devon
If you can employ a vertical rib of steel that would easily sort it. Box, channel, angle or even flat strip screwed to the timber. A vertical rib of 40x3mm would be hard to distort...although if flat strip is used it wold need the support of adjacent timber to stop it twisting out of plane.
 

recipio

Established Member
Joined
16 Jun 2008
Messages
272
Reaction score
62
Location
ireland
You should be fine with that design. With a torsion box its the glue line that gives strength so you would need to glue the 6mm vereened ply properly with clamps - don't use contact adhesive. One method I have used for thick shelving is to use ( new ) flush doors. They are nothing but torsion boxes after all. When you cut into them you expose the 'eggbox' interior and you just need to glue in a slat between the outer skins along the cut line and the strength is restored. You can veneer over them if needed but don't use a vacuum press or they may collapse ! They are 880 wide so ideal if your alcove is 440 or less.you will get two shelves from one door
 

partsandlabour

Established Member
Joined
21 Aug 2013
Messages
81
Reaction score
22
Location
Newcastle upon Tyne
Use another span left to right. I've done loads of these. Usually 2x1 battens around the walls. 2x1 Front span, 2x1 mid span. 6mm Birch ply well glued with pva and pinned. Front face capped off with more 6mm Birch glued and pinned. Very solid. The torsion box really works. Most of ones I've done have been around 1200, but I've done longer and used 3x1. I've been working on having an overall shelf thickness of roughly 5% of the span, which is probably overkill but it works. The shelves are very robust. If you're not piling loads on books on then I reckon your 2x2 will be fine.
 

siggy_7

Full time tool collector, part time woodworker
Joined
25 Sep 2011
Messages
591
Reaction score
50
Location
Gloucestershire
I made a 2.4m shelf of otherwise similar dimensions in my kitchen, full of books and tall jars etc. It is rock solid - fixed to the wall with epoxy bonded studding. The span isn't an issue if you are supporting from the rear of the alcove rather than the sides.
 

Alie Barnes

Established Member
Joined
16 May 2007
Messages
239
Reaction score
0
Location
Reading, Berkshire
What would people suggest as a good size of wood to use for the battons and front i was thinking of 44x44mm i see a lot fo 3x2 etc is this inches? im just use to metric so struggling to work out wood sizes.

Thanks
 

sunnybob

wysiwyg
Joined
11 Oct 2014
Messages
8,399
Reaction score
162
Location
cyprus
3 x 2 is inches. 44 mm is 1.7".
I'm surprised your woodyard is working in mm. Even here in Cyprus where metric is the official language all the woodyards work in inches for lumber sizes.
 
Top