question about tramming a square column mill

Dan_S

Dan_S

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Bear with me for a moment on yet another tramming question.

On a square column mill drill the following parameters are fixed (unless you have a really big mill to re-machine stuff).

1. the angle between the x and Y Axis. Ideally it's exactly 90 degrees but it's most likely out by some small amount.
2. The relationship of the head/spindle to the column in the y axis is fixed (no nod). Ideally it's exactly parallel, but it's most likely out by some small amount.


The adjustable parameters are:

1. the angle between the column and the y axis
2. the angle between the column and the x axis
3. the angle between the column and head/spindle


For #1 you can use the standard tram method of sweeping the table and then shim the base of the column accordingly.

What I'm stuck on is #2 and #3.

To me the correct method would be to use a cylindrical square or precision angle plate to adjust the column in the x axis relative to the table, and then use the standard tramming method to sweep the table to adjust the head/spindle true to the table and column (in the x axis) at the same time.


Does that make sense? How is everyone else doing it?
 
I shimmed the column to the table sweaping the table. Squared the column to the table by running the head up and down with a dti and a precision square. I have a G0704 the head rotates . Sweap the table for that. From there indicate the vice in. And everything comes out square.
 
Dan_S said:
Bear with me for a moment on yet another tramming question.

On a square column mill drill the following parameters are fixed (unless you have a really big mill to re-machine stuff).

1. the angle between the x and Y Axis. Ideally it's exactly 90 degrees but it's most likely out by some small amount.
2. The relationship of the head/spindle to the column in the y axis is fixed (no nod). Ideally it's exactly parallel, but it's most likely out by some small amount.


The adjustable parameters are:

1. the angle between the column and the y axis
2. the angle between the column and the x axis
3. the angle between the column and head/spindle


For #1 you can use the standard tram method of sweeping the table and then shim the base of the column accordingly.

What I'm stuck on is #2 and #3.

To me the correct method would be to use a cylindrical square or precision angle plate to adjust the column in the x axis relative to the table, and then use the standard tramming method to sweep the table to adjust the head/spindle true to the table and column (in the x axis) at the same time.


Does that make sense? How is everyone else doing it?
Click to expand...

I think that you are using a different coordinate system from the rest of us. To me the spindle axis is Z, Y is toward the column, and X is left-right. To tram I shim the table (but my machine is weird: you probably want to shim the column) until its surface is perpendicular to the spindle axis. There's nothing else to adjust. X and Y are fixed by the construction of the table.
 
John Hasler said:
I think that you are using a different coordinate system from the rest of us. To me the spindle axis is Z, Y is toward the column, and X is left-right. To tram I shim the table (but my machine is weird: you probably want to shim the column) until its surface is perpendicular to the spindle axis. There's nothing else to adjust. X and Y are fixed by the construction of the table.
Click to expand...


We are using the same one, but I might not be explaining my point of view very well.

If you are standing in-front of the machine, the x axis is left to right, the y axis is forward & back, and the z axis is up and down. But you really have 2 Zs (if you will), the head moving up and down the column and the Quill moving up and down in the head. Ideally you want them both to be square to the table in the x & y directions. You can tram the column to the x & y using shims, but you can only tram the spindle to the x by rotating the head. Does that make more sense?
 
There are Four parameters to tram on small mills.
The obvious two are (assuming your sitting in front of the mill)
1) Column tilt forwards and backwards
2) Column tilt left and right

These are corrected by shims at the base of the column.
Or if you have a column that tilts left / right - then no shim is required for (2) - just undo the nut and correct it.

What is less obvious is the angle that the head is mounted on the column has two adjustable rotations.
a) the head may be tilted forward or backwards
b) the head may be tilted left or right

The (1) and (2) above, are column to slide alignments
The (a) and (b) are, head (or spindle ) to column alignments

Say (a) and (b) are out of alignment but (1) and (2) are aligned.
If you put a laser pointer in the chuck, the dot on the table would move as the head is raised

The head normally has two castings bolted together with four bolts.
By shimming the lower or upper bolts between the castings - you can adjust (a)
The other adjustment (b) is done, by using the slight play possible by loosening the four bolts, and rotating one casting with respect to the other.

I find it easy to do (1) and (2)
Not so easy to do (a) and (b)
 
kwilliam said:
There are Four parameters to tram on small mills.
The obvious two are (assuming your sitting in front of the mill)
1) Column tilt forwards and backwards
2) Column tilt left and right

These are corrected by shims at the base of the column.
Or if you have a column that tilts left / right - then no shim is required for (2) - just undo the nut and correct it.

What is less obvious is the angle that the head is mounted on the column has two adjustable rotations.
a) the head may be tilted forward or backwards
b) the head may be tilted left or right

The (1) and (2) above, are column to slide alignments
The (a) and (b) are, head (or spindle ) to column alignments

Say (a) and (b) are out of alignment but (1) and (2) are aligned.
If you put a laser pointer in the chuck, the dot on the table would move as the head is raised

The head normally has two castings bolted together with four bolts.
By shimming the lower or upper bolts between the castings - you can adjust (a)
The other adjustment (b) is done, by using the slight play possible by loosening the four bolts, and rotating one casting with respect to the other.

I find it easy to do (1) and (2)
Not so easy to do (a) and (b)
Click to expand...



(a) & (b) can be corrected by taking measurements like this, and then shimming/rotating the head.
https://www.youtube.com/watch?v=qGdptphPWGs


What I'm trying to figure out, is how to take a measurement to validate (1) & (2). The issue as I see it, is that the table can't be used as a reference surface like it can for (a) & (b).
 
Dan_S said:
(a) & (b) can be corrected by taking measurements like this, and then shimming/rotating the head.
https://www.youtube.com/watch?v=qGdptphPWGs


What I'm trying to figure out, is how to take a measurement to validate (1) & (2). The issue as I see it, is that the table can't be used as a reference surface like it can for (a) & (b).
Click to expand...

If I understand correctly you are saying that the spindle axis could be perpendicular to the table surface but the head as it moves up and down might not be moving parallel to the spindle axis?
 
John Hasler said:
If I understand correctly you are saying that the spindle axis could be perpendicular to the table surface but the head as it moves up and down might not be moving parallel to the spindle axis?
Click to expand...


Yea, basically you need both the column and the spindle to be perpendicular to the table in the X and Y axis. If the column isn't perpendicular, any time you move the head you will induce a small offset in the X or Y direction.
 
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