X3 (Or similar mini mill) Rigidity Q

Hi,

Been trying to get a few responses to help out some troubleshooting on my X3 mill over in the subforum, but not too many there it seems.

I am curious to know what readings people get- With a dial base on the mill table, and indicating on the column itself, maybe 12" above base mount. Pushing/pulling on headstock or top of column- do you see any play?

Mine has play(or flex) - a good bit. I cannot find anything that would cause it. Ive stoned the base mounts, checked everything over. Curious if other mills show similar play.

Hi, welcome to the real world....all metals are flexible and have spring like tendencies.

In mills the column is the weak link......if the aspect ratio of the base width and depth to the height is big, you will get deflection the higher up the column you go.

The rule for a beam is, before it can support the designed load IT MUST DEFLECT.....if the load is sporadic, at some point the column will deflect and keep moving, and continue with the smallest of pressures.

There is a name for it, and that is resonance.....if you have a resonant factor present when the cutter is hitting the work piece, the blows imparted by the small cutter teeth will be amplified as vibration when the column reaches resonance.

You would have to use a different speed and feed rate to detune the resonance from the column when it reaches critical levels.

You can "retune" the column by changing it's mass to change the point where resonance occurs, and that can be as simple as adding some weight to the column at some point high up, but a simple brace attached to the column head and a nearby wall will for most occasions absorb the vibration by restraining it.....the wall acts like a shock absorber.

Standing on a concrete floor a mill with a resonance factor from a material/cutter/rpm combination can make the windows rattle in sympathy with the vibration of the cutter.

It's like a tuning fork.....vibrates at a certain frequency.
Ian.