poor wood choice

[bigjase]

Hi i used 18mm ply, 3x2 frame work on the under side. I am going to beef it up with 4x4 posts across width onto 3x2 hopefully that sorts the level out, job for tomorrow night

[brainbug007]

I used chip and it was horrible. by the end of the chassis build it had started to sag which caused all kinds of measuring & leveling problems. I'd use thick ply supported well!

[TheArf]

I opted to use framing timber sandwiched between two sheets of 19mm MDF and still go a touch of sag in the middle but once chocked up the middle it stayed flat

Arfon

[baz-r]

i avoided the sag issue buy having my build board directly on the floor that was level and packers all the way round the outer edges until my frame was fully tacked up
just used stright 3x2 all the way round a 18mm std ply sheet then an + shape brace from the centers