With that in mind I have priced and sourced everything required for cheap work benches in the UK. Wickes is the real key, everything under one roof so you can pick it all up at once. With this design I was able to make 5 benches, 12m of workbench for £100. These 5 benches were built for the newly created Leicester Hackspace. If you're in Leicester on the 1st of March, why not drop by for the grand opening.
Step 1: Gathering the Materials
20x Studwork timber 38x 63x 2440mm @ £2.38
3x MDF Sheet 12x 1220x 2440mm @ £13.83
3x 5.0x80mm screws @ £2.30
1x 4.0x30mm screws @ £1.89
Total = £97.88
If you want a slightly sturdier bench I would recommend moving to the slightly larger studwork
20x Studwork timber 38x 89x 2440mm @ £3.50
3x MDF Sheet 18x 1220x 2440mm @ £16.06
If you want a slightly easier assembly job switch up to Wickes Easy drive screws (these come with a bit so you know you have exactly the right size bit for the screws)
2x 5.0x80mm screws @ £6.98
1x 4.0x30mm screws @ £3.50
Possible upgrades = £135.64
Step 2: Bench Design
To form the leg frame, cut the timber into 4 parts, 2440 splits into 2x 800mm and 2x 400mm parts, two verticals and 2 cross bracers. The cross bracers should be fixed between the verticals to form a leg frame.
The leg frame should be fixed to the horizontal beams, 500mm from each end of the bench. Bringing the legs in from the ends a little limits the bow from spanning the large distance, but the bench will tilt if someone sits on one end of it. The leg screws should be placed diagonally across the joint, this avoids the frame screw positions but also provides maximum strength against the leg rotation.
When screwing the legs down screw 1 screw in first, then use a set square to make sure the leg is vertical before putting in the remaining three screws.
The mdf sheet needs to be cut in half length ways and it will form the surface for 2 benches. Screw the mdf down to the frame using a generous number the 30mm screws spaced around the top. Don't forget to screw right up to the ends of the sheet and also to get some screws into the cross braces of the frame.
Hopefully that about covers it, the pictures make it much clearer.