MDF

[16miller]

I have to prepare a surface to sit on top of a dexion frame to take a Lathe which weighs aroung 300lbs and has two projecting feet as fixing points. In general wood of any kind is frowned upon for supporting a lathe owing to natural movement with changes in humidity and temperature thus destroying the accuracy of a precise levelling. Will MDF of approx 25mm thick and 1400mm x 650mm area react in the same way as timber, it would be sealed on all surfaces to prevent any ingress of oil but this would not be to any great extent.

Any advice appreciated

Derek

 

[DAZB]

It should be ok as long as it doesn't get wet. Another option might be to cut down a Solid Core Fire Door. These are 44mm thick and very sturdy. As you are going to seal all surfaces then either option above should work fine.

 

[masona]

You can get 25mm exterior plywood which is sealed with waterproof glue,very strong but not cheap.

 

[MANDATE]

I doubt if any of the suggestions will be entirely satisfactory.
Firstly is the dexion frame sturdy enough and secondly a platform 650mm by 1400 mm made from mdf or ply or door will not prevent some twisting.
and flexing. A good strong solid bench with timber about 2in thick and 9 to 10in wide may suffice.
You could use 2 pieces of RSJ or channel iron with spacers between to form a solid base to which you can bolt down the headstock and tailstock

 

[masona]

Normally the lathe sit on a concrete bed with rawbolts.

 

[Scoby_Beasley]

If its a hobby lathe, go with the timber. If its ya living, rsj's are the only way to go and well set into the ground (but you'd know that). Stability is everything.
As Masona says, usually a concrete bed, kick the lathe, kick it again and when casualty let you go home with 5 broken toes, you know your lathe aint gonna move !!!!!