Aligning the head of a milling machine is essential if the head has been tilted for angled cutting. When you move it back to zero, it is sometimes still just a bit off, so using a dial indicator is the most accurate way to make sure that this misalignment is taken care of to prevent even the slightest errors when cutting. Once the head is adjusted and the readings are good, you can be sure that all of the parts you make on the milling machine will be accurately machined, regardless of the operation.
Things You'll Need
- Dial indicator
- Dial indicator holder
Place a dial indicator with a holder on the spindle head of the milling machine. Tighten the nut with a wrench to keep the indicator secure, making sure that the holder and indicator are straight. It's possible to tighten them too much, resulting in an angled indicator, which will give you a false reading.
Disengage the spindle head gear so that the spindle spins freely. Slide the gear between the high and low settings while also turning the spindle with your hand manually. This action will disengage the gear so that the spindle spins by hand for ease of use while aligning the milling machine.
Lower the spindle of the milling machine down toward the table. Use the quill feed handle, located to the right of the spindle. This will lower the indicator so that you can place its tip on the table in order to align the head with the table, which is essential to accurate machining. Engage the quill feed lock to keep the spindle down toward the table.
Push the indicator needle down so that enough pressure is applied to register on the dial. Spin the indicator 360 degrees, watching for any movement of the needle on the dial. If there is none, the head is aligned with the table.
Loosen the four bolts on the front of the spindle head if there is movement of the dial indicator when the needle is to the left or right of the spindle head. Tilt the head to align the bolt located near the four bolts you loosened. Re-check with the indicator until the reading is exactly the same on either side and re-tighten the four bolts.
Loosen the three bolts to the right of the spindle head arm. Tilt the head back and forth to reach the same reading at the front of the spindle head as well as the back, using the spindle arm movement bolt. When you do, re-tighten the three bolts; the head is now aligned.
- Photo Credit Milling machine is cutting metal image by Andrei Merkulov from Fotolia.com