Making a raised workboard - help retaining flatness?

[Dissolve]

Hello,

I have my main workbench alongside a wall in my home workshop, It would be very useful to make a rasied workboard (two sheets of 18mm MDF for instance with spacer blocks in between to allow clamping all round smaller work pieces.

I have tried doing a "dry run" using off cuts of 18mm MDF stacked up and spaced evenly apart in a 3x3 "grid" of sppacer blocks, but with clamps on each block the top remains somewhat unflat. Would using a hardwood frame in between the MDF sheets be a more accurate way of retaining the boards flattness?

I could obviously plane these accurately and glue them together with simple butt joints before clamping the two boards together?

Any ideas?

 

[carlb40]

How about using 2 layers of 18mm mdf for the top to give it extra stiffness?

 

[SammyQ]

Torsion box!!

Sam

 

[Stu_2]

I've made a top for one of my work surfaces which I find really useful for clamping smaller jobs. As the surface was already quite high, I needed to keep the overall height increase to a minimum, while still being able to use rail clamps for general clamping. The slots were originally used to simply allow the clamps to pass through the table, but have proved very flexible for positioning, too.

Hope that helps.

Cheers
Stu

 

[DeepBlue]

If you do want to go the whole hog, Marc Spagnuolo did a great video on torsion boxes:

http://www.thewoodwhisperer.com/videos/episode-18-assembly-table-torsion-box/

 

[MMUK]

How about using something more structural than the satan spawn known as MDF?