Bed "Flatness"

[Nthkentman]

Evenin all....... If I'm using a spoil sheet of 3/4" ply fixed to the slotted Tee alloy bed is it a good idea to machine the entire sheet to give better flatness for when I'm machining thin material like 2mm MDF ?


Or doesn't anyone really bother ?

[EddyCurrent]

If you are cutting right through the MDF and you don't mind going slightly into your ply spoil board then I don't see why you should skim it. The only thing that might occur is that if the MDF is sloping badly then any vertical cuts would not be at right angles to the MDF surface and that may or may not have consequences for your application e.g. parts not fitting together correctly.
If you intend to make cuts that do not go right through the MDF then the ply would need skimming, probably using the biggest diameter tool you have.
Be aware that if the spoil board extends beyond the footprint of your tool travel you would effectively create a pocket in the ply and your MDF would need to fit inside that pocket to be flat.

[gianluca_g]

I would say that having the bed of the machine nice and flat is ALWAYS a good idea :)

[JAZZCNC]

If your mostly profilling then it's not so critical but if your pocketing or engraving or chamfering then it's absolute must.
Personally I like my bed flat as it's the foundation for any work under taken and that can change daily so I always surface any spoil board first time around then access on type of work and hammer it's had.!

Often My bed is divided into 2 halfs one has a spoil board that gets chopped to bits for profiling etc that isn't critical on edge angle and the over half is uncovered which I use for accurate work and Dont cut thru.