z axis mini mill, cutting in between ways?

[crl1_1]

So far I have added the z axis ballscrew on the side of the mill, however I have noticed an irregular movement. It seems that when the machine is moving down it applies pressure to the left, causing a slight tilt and the opposite happens when moving up. I know this can be corrected by tightening the shim between the ways. I was thinking of cutting a slot between the ways but I am a little concerned about causing stress fractures or cracking the casting with use. I think attaching it this way would not cause this irregular tilt . Any thoughts on this?

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[crl1_1]

I wanted to say thanks to (nobody) for all the input , I ended up cutting between the z axis ways

[pippin88]

I suspect people didn't understand what you were talking about (I didn't).

How does it perform now?

[peteeng]

Hi CRL - You do need to be more precise with your questions to get an answer. In #1 yes you just adjust the gib (shim) to remove play in the way. But you have moved the drive to central but you still need to adjust the gib. Did the mod work? Peter

[cyclestart]

Sometimes there are no responses because no one knows the correct answer. My gut feeling is little structural integrity has been lost but someone skilled in FEA software can answer without depending on intuition.
The weakest part of the tilting mini-mills is the base-to-column connection. It takes only a small amount of pressure on the column to get deflection, a brace helps a lot.

[dazp1976]

I did the solid column upgrade on mine and machined it a little to get 150mm on the Y axis.
Rigity was miles better.
I had the same twist action on my head driving down the side. A double nut may have made a difference.
The downside with slotting out the center is you won't be able to use it as a manual drill again as the rack teeth will no longer attach.

I never really liked the machine as a cnc that much in the end.
The small table vibrates and twists all over the place.
Was made worse by opting to build it using thrust bearings and not angular contact ones.

I upgraded to a PM25 type machine as soon as I could.