1. Tramming the Toolhead on a Vertical Milling Machine
A step-by-step procedure
Created by: Alexander J.W Surra

2. Why do we tram the toolhead?
Tramming is squaring the spindle to the table in both axes.
an essential step to accurate work on the vertical mill.
Due to the versatility of the machine, perpendicularity of the spindle to the table must be established.
The factors that are involved include:
Number of directions the head can move
Various work holding devices to mount to the table

3. Tools Required ¾” Wrench Needle-Type Dial Indicator Drill chuck/collet
Indicator holder

4. Preparation
Stone table and the bottom of the work holding device to remove high spots
Wipe oil and other contaminants from table and work holding device with a rag
EVERYTHING IS MEASUREABLE!
Dirt, oil, knicks, high spots, chips, etc… Be sure to eliminate careless errors through cleaning.

5. Attach the Indicator to the Spindle
Check the taper for contaminants, and place either a collet or a drill chuck into the spindle.
Tighten the drawbar and secure the indicator into the collet or drill chuck
Or, place indicator holder on the outside of the spindle
Lock the quill
Put the spindle in neutral

6. Begin Inspecting Toolhead for Perpendicularity
Crank the knee up until the table puts about .005” load on the indicator needle.
Zero the indicator by spinning the bezel
Rotate the indicator 180°
Note the difference between first and second reading

7. Adjust the X axis
Slightly loosen the four ¾” bolts that face the operator and hold the toolhead in place.
Turn the adjusting screw so the indicator reads half the difference from the first reading to the second.
When adjusting remember:
To raise the spindle (less pressure on the indicator) on the left side of the machine turn the screw CCW (push the wrench)
To raise the spindle (less pressure on the indicator) on the right side of the machine turn the screw CW (pull the wrench)

8. Verify Toolhead Perpendicularity in X Direction
Gently snug the four ¾” bolts facing the operator.
Rotate the spindle 180° back to the starting point, and verify it is the same number that the other side was adjusted to.
Zero the indicator using the bezel

9. Inspect Toolhead Perpendicularity for Y Direction
Rotate the spindle 90°
Slightly loosen the three ¾” bolts that tighten the toolhead knuckle to the ram.

10. Adjusting the Toolhead for Perpendicularity in Y Direction
Adjust the head until the indicator reads zero, like the sides do.
When adjusting remember:
To raise the spindle (less pressure on the indicator) on the back side of the machine turn the screw CCW (push the wrench)
To raise the spindle (less pressure on the indicator) on the front side of the machine turn the screw CW (pull the wrench)

11. Verify Toolhead Perpendicularity in Y Direction
Rotate the spindle 180°
The indicator should be to the rear of the machine table now, and it should read zero without changing any settings.
Gently snug the three bolts that secure the ram knuckle.

12. Verify Toolhead Perpendicularity
Rotate the indicator 360° and verify that at each quadrant, the indicator reads zero
Once satisfied, secure the four front bolts as well as the three side bolts
Remove the indicator, taking care not to bump or jar this precision instrument

13. Review Which direction should be checked first for perpendicularity?
How much do you move the head when checking the opposite side of the table?
When checking the Y axis, do both front and back have to be zeroed?
Does it make a difference if the area checked is bigger or smaller? (i.e. the indicator has a larger swing)
When the spindle is moved up with an adjusting screw does it add or reduce pressure on the indicator?

14. Any Questions?