>sure, you have much more experience in that than i have..
>i already said i have no mill (until now).
>maybe it is also the tip angle of the milling bit.
>i can imagine it this is very flat angle the difference in with would be
>much more
>than with a narrow tip angle..
You can buy End Mills. They are flat and the milled channel is uniform.
Useful, also, for Rubout.
>what is the problem with wider boards?
>isn't it flat enough in the middle where no clamping screws are?
It is not, for sure!
>maybe stromger vacuum may help to keep it down...
No way for the amateur tool.
Use double face (carpet tape) adhesive tape to keep the PCB as flat as
possible on the machine's bed.
Also I use a depth tool (that 'foot') with angled mills. It is simple to
construct with a lathe.
>how do you set the height/depth of the milling bit (the z axis).
>have you set this to a constant value determined by experiments?
>
>so to conclude this i think the following is true:
>these problems depend very much of:
>used mill
>pcb quality
>mill bit tip angle
>pcb size
>
>and maybe a foot if needed if it doesn't work fine without.
>with using a foot also a vacuum cleaner is needed.