Thread: Building a BIG desk

people sit on desks, or lean on desks.
I'd beef up the front with a rail


BTW, are you sure you entered the expected loading into sagulator and used consistent units?
1500+ seems an awful long unsupported span for MDF

Originally Posted by ian

people sit on desks, or lean on desks.
I'd beef up the front with a rail


BTW, are you sure you entered the expected loading into sagulator and used consistent units?
1500+ seems an awful long unsupported span for MDF

I should have shown a rear view as well. There's a 200mm rail/edging strip along the back of the main desk and return. According to sagulator it doesn't matter which side this is on.

EDIT: Here's a view from the rear

I now know of the existence of the Sagulator ! Thanks.

Did you use "fixed" or "floating" in the Sagulator? I couldn't see definitions for these.

The Sagulator quote about edging says no difference between edge and underside, not between front and back, which makes me wonder if "fixed" assumes the back of the shelf is supported, and the edging is stiffening the front half of the shelf. In this interpretation, your design effectively has no edging.

This is just wonderings from a Sagulator newbie...

Cheers,
Andrew

Andrew,
I ran the calculations for both fixed and floating and the difference was not great. I'm assuming it refers to how the the ends of the shelf are fixed. i.e. the difference between a shelf just sitting on end supports as opposed to being screwed/glued/nailed to them.
The biggest difference to the amount of sag lies in having an edging .Even an edge of say pine at the same thickness as the desk top will make a big difference.

The sag figures assume that it's a single piece shelf. My desk top is not and I'm sure the join will make a difference. Hope I don't have to put a leg/support there as that's where I'll have the computer.

Originally Posted by snowyskiesau

I should have shown a rear view as well. There's a 200mm rail/edging strip along the back of the main desk and return. According to sagulator it doesn't matter which side this is on.

Originally Posted by snowyskiesau

I ran the calculations for both fixed and floating and the difference was not great. I'm assuming it refers to how the the ends of the shelf are fixed. i.e. the difference between a shelf just sitting on end supports as opposed to being screwed/glued/nailed to them.

that's my undestanding of the difference
floating would be sitting on shelf support pins
fixed is rebated and/or screwed and/or glued to the uprights

The sag figures assume that it's a single piece shelf. My desk top is not and I'm sure the join will make a difference. Hope I don't have to put a leg/support there as that's where I'll have the computer.

I think you're being hopeful

my desk at work is a similar design to yours, but ~32mm thick and the spans would be less than 1500

Originally Posted by ian

I think you're being hopeful

my desk at work is a similar design to yours, but ~32mm thick and the spans would be less than 1500

Ian,
I'm trying to best utilise the space I have using the materials on hand. Still, if there's a better way to do this, now's the time for me to find out!. I want to have the computer keyboard./screen in the corner hence the preference for no leg/support in that position.
The rest of the desk surface will be for electronic bits and pieces which are fairly light.

The desk I had in Sydney was 3600mm long supported at each end and along one edge with 2 supports cantilevered out from the wall at 1200mm intervals. In the 10 years I had it, it never sagged! Wish I could do the same here but rented property ...

My desk is in part 1600mm long and has only the end supports but has a Deep piece of timber running the full length of the desk at the rear but does not continue on down to the floor.
The front of the desk has no other supports and after 5 years of use, so far has not sagged.
Desktop is 22mm thick and looks like its veneered particle board. My point being, you should have no problems with the sag factor.

Originally Posted by snowyskiesau

The desk I had in Sydney was 3600mm long supported at each end and along one edge with 2 supports cantilevered out from the wall at 1200mm intervals. In the 10 years I had it, it never sagged! Wish I could do the same here but rented property ...

you might be able to achieve the same effect by attaching stifferners to the rear rail every 900

To join the top have you seen these?

Attachment 197844

used to connect our kitchen bench corner joins

Yes I've seen those joiners. As I'll need to assemble the desk in the shed so I can route the edges (bullnose profile), something that doesn't need to screw into the MDF is needed, these should do the job well.

Probable get some from Elraco as I need to order some bed hardware and some table brackets too.

Decided to get stuck into this and cut up the boards (25mm MDF 3600 x 1200 - heavy!).
After attempting to cut it on the ground, suddenyl remembered "I've got a hoist!"

Lifted it onto the newly made sawhorses and cut most of the pieces I need. My legs and back feel much better than if I'd tried to do it at ground level. Must put a big sign on the hoist saying 'USE ME!"

If the hoist is out of site it can be out of mind.

Dave J said the same thing.

If I'd remembered I had it, I wouldn't have broken my nice new drill press the other day getting it out of the van.

Also applied to the sign you are going to make. Try to keep it in sight.