Face mill finish

Well, in theory you are correct.

Tomorrow I will double check the squareness of the column to the table again. It must be pretty close because when I used the facemill, the stepover raised level was gone completely
whereas before I did the column alignment there was a small raised level on the piece, as can be seen in the very first post.

Earlier I read 0.4mm out of square on a 30cm swipe. I will fine tune this and see what happens.

Edward

EDIT video included:

Forgive the crappy video, but it shows how I measured it. First the top of the rod, hardly any runout, less than 0.01mm. on either side of zero.

Then again at the low end of the rod, notice the equal deflection either side of zero, around plus/minus 0.05mm

https://www.youtube.com/watch?v=V4IK...ature=youtu.be

Quote:

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Originally Posted by Edward

before I did the column alignment there was a small raised level on the piece, as can be seen in the very first post.

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You keep mentioning column alignment but what were you using to check the angle between the column and table, given that you chose to align that first?

But do you know the Bar is Perfectly round and straight.? If the bar isn't calibrated test bar and the collet high quality then your wasting your time. However I think for machine this size and quality that's good going to get or should expect.!

Edward - your very first adjustment/measurement didn't do what you thought it did. Putting a dial gauge in a collet and winding the table back and forth only tells you that the table is flat. You would get the same result with the column at 45deg, say! The only useful measurement is the turn-round/tramming test where you keep the table still and turn the spindle. However, this only tells you that the spindle is square to the table. The column could be tilted, and the head off-square to the column by an equal and opposite angle, leaving the spindle square to the table and you would not be able to detect this. The test to detect this is to tram the spindle, probably by shimming the column base as you have done and using the spindle turn-round measurements, then with your test bar in a collet and without turning the spindle, clamp dial gauge to table and then run head up and down column, note any variation, then run spindle up and down in head (drilling movement). If these match, head is square to column. If not, then there's no simple fix but at least you can double-check manufacturing accuracy.

Quote:

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Originally Posted by Edward

The indicator holding prong is actually in the spindle, held inside an 8mm collet. The measuring lever is just touching the table. Therefore any readings of the table are relative to the spindle/head/column assembly. Since the only thing that moves is the swipe east to west of the table, , the reading will change if the table is not horizontal.

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Incorrect, what you will get is the error between the plane of the table ways for the moving axis and the table surface, this will remain constant with your indicator mounted on any fixed point on the machine chassis, the column, and if clamped still, the head, are simply extensions from the fixed chassis of the machine.
If there is an angular error between the plane of the table surface and the ways then no amount of jiggling your column, head or spindle angle will "adjust" this away, the only way to correct this is by removing material ;-)