Face mill finish

[magicniner]

Doesn't the column bolt down to the base with 4 bolts?
If so you can shim front to back, then shim side to side.

[Edward]

Yes, as I said in post No. 4, that's how I did it, and it's perfect. But aligning the column is not enough, you also need to align the spindle axis.

To give you an example, if you tilt the whole column 20 degrees to the right, your spindle will also tilt 20 degrees to the right because it is attached to the column, but you want to be able to tilt both independently.

And the reason is that column and spindle don't come from factory 100 percent parallel to each other, unfortunately, if they did, then shimming the column would be all that is needed.

If there is no way of adjusting for this parallelism between column and spindle, well, you are buggered basically.

Edward

[magicniner]

Yes, as I said in post No. 4, that's how I did it, and it's perfect. But aligning the column is not enough, you also need to align the spindle axis.

To give you an example, if you tilt the whole column 20 degrees to the right, your spindle will also tilt 20 degrees to the right because it is attached to the column, but you want to be able to tilt both independently.

Edward

You don't tram by measuring the column with a non-angle adjustable head, you tram by measuring the error with a spindle mounted indicator.

Calculate the error in parts which will result, if it's not acceptable strip the head off and scrape the dovetail to correct.

[Edward]

I have a feeling we are talking at cross purposes:)

Forget the word "tram" for a minute.

Basically you align the column first so it is square to the table.

Then, and only then, you align the spindle to the table. In that order. That's provided you can do it. Not possible with a fixed head.

Alternatively, you make sure that column and head run parallel to each other, then you just square them to the table.

I guess modifying the dovetails would do it, if properly done, but that's way beyond my scope.

Edward

[magicniner]

Basically you align the column first so it is square to the table.

Not if you can't independently adjust the orientation of the spindle to the column you don't, you rely on the manufacturer having made the head align to the column, if they didn't you send it back or adjust the fit of the head to the column to correct the error.

[Edward]

Agreed, as I said above:)

Luckily the error is something I can live with.

Edward

[magicniner]

So the only thing I can think of is somehow tilting the spindle itself, but it may be tightly enclosed in its housing so that there is no room to shim it to one side.]

You could bore the hole for the spindle assembly slightly over-size and in alignment then sleeve it back to the correct size but scraping or machining the dovetail opposite the gib strips is a far easier way to achieve the required adjustment.

[Edward]

Thank you, re-machining to dovetail on the opposite side to the gibs so that head and column run completely parallel seems like a solution. But it is way beyond my scope, something better left to the experts:)

Next mill will have a head adjustment, that's for sure:)


Edward

[Edward]

Latest news on this subject:)

I came across this video by hossmachine about tramming the head to the column.

I stuck a rod in the spindle and followed his procedure exactly, setting up my indicator like he has done, as I have the same bars. I can't adjust the head like he can, as mine is fixed but I was nevertheless very curious to see how far off my mill head was using this method.

First I jogged to the top of the rod, rotated the spindle by hand and zeroed it to be exactly half way between the maximum plus and minus readings of the runout. Since this was measured at the top of the rod, the runout deflection was quite small.

Then, without touching anything, I simply jogged the Z axis so that the indicator was at the bottom of the rod. I rotated the spindle again and the deflection on either side of zero was exactly the same. I did the same to the Y side of the rod. So I guess this mean I have been worrying about nothing?

Provided this method is good, and I am only going by his video, then I guess I am OK.

Edward

Tramming video by Hoss here:

[magicniner]

So if your spindle is parallel to your Z axis movement and you have your column square to the bed there will be no error when you check the tram?