9.5 Work Setup
Micky R. Jennings
Setting up the work on a milling machine could be as easy as clamping a piece of material into a vise; however, sometimes there is more to it. Sometimes the angle of the head needs to be adjusted, and sometimes the machinist needs to know the exact center of the work or just a couple edges. The operator of the mill must know how to perform all of these setup configurations and more. Following a work plan and studying the print are the first steps to deciding which work setup is right for each operation.
Tramming the Mill Head
Trammingthe head of a milling machine is the process of aligning the rotational axis of the spindle to be perpendicular to the table. The tramming process is carried out by adjusting the tilting and nodding functions of the joints in between the head and the ram. The amount the head is out of tram can be measured by attaching indicators to the spindle, rotating it to different points on the table, and reading the difference in the values on the indicator.
Step by step process for checking and tramming the milling head:
- Remove the vise.
- Place a tramming device into or onto the spindle of the milling machine. This device should have at least a 4″ reach from the center of the spindle.
- Install an indicator on the tramming device.
- Place the spindle in neutral. This is for ease of movement.
- Center the table.
- Raise the quill to the top of its travel and lock it.
- Raise the knee, so the table comes up and into the motion of the indicator and lock it. Generally, about .020 is enough. Too much indicator preload may harshly bump the indicator as it travels across the tee slots, potentially altering its readings and position.
- Move the spindle so the tip of the indicator does not fall into a scraping mark or damaged spot.
- Zero the indicator.
- Slowly rotate the spindle around the table, checking opposing directions to determine if the tilt or nod may need adjustment.
- The direction most out of tram should be addressed first. For this demonstration, the tilt will be adjusted first because it is slightly easier than the nod.
- Rotate the spindle to the furthest left and check the indicator reading. The difference between the right and left sides is the amount out of tram in the side to side tilting motion. If the difference from one side to the other is more than .001, the tilt must be adjusted.
- Start by loosening the four fasteners on the face of the milling head.
- Adjust the tilt by half the amount the head is out of tram in the side to side direction. This is possible because the pivot point is in the middle of the two indicator positions. As one indicator reading gets smaller, the other one gets larger until they meet.
- Tighten the four fasteners to 50 ft./lbs.
- Recheck the tilt tram. If it is still out, repeat the process of adjusting.
- Rotate the spindle and move the indicator to the front of the table.
- Zero the indicator again.
- Rotate the spindle and move the indicator to