How big is the cutter?
How sharp is the cutter?
How deep is the cut?
What is the material?
Is the machine bolted down?
I have found that a new 10mm carbide cutter on stainless steel taking a skim cut has a vertical load around 150 grams.
A worn out cutter needs 5KG.
Put some scales under the head, and a DTI from the table, then increase the pressure slowly.
5KG gives me over 0.001" -- 30 microns measured, and that is with the column bolted to a brick wall.
Without the bolt it is more than 20 times that.
Some is column flex, some from the vertical gib, and most from the base flexing.
Don't blame the Chinese. That's as good as it gets for that much metal.
With some tweaking I am maintaining 2 microns in Z all day, and I am using balance weights CNC lowered on to the head to balance the cutting forces.
1. Use a brick wall.
2. Get the gibs PERFECT.
3. Use sharp cutters.
4. Know the limits of the machine. It is most physics limits.:idea:
Seeing nice criss-cross cuts, all directions, (is it square?) requires better than 0.0001"
:cheers:
Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.