How to Mill Round Stock Without a Lathe

Material that lacks edges must be checked for straightness before being machined.

Round stock has no sides, so it is much more difficult to hold in a vise or fixture. Most round stock machining takes place in a lathe, but round stock can be milled on a manual milling machine such as a Bridgeport, or on a more complicated CNC mill. CNC mills (computerized numerical control mills) use sophisticated computer to cut material through the automated movement of the cutting tool. In order to cut round stock on any mill, it must be held tightly and check for straightness using a dial indicator so that the dimensions come out correctly.

Things You'll Need

• Vise or Fixture
• T-bolts
• Wrench
• Dial indicator

Instructions

1. Place a vise or fixture on the work table of the milling machine. A vise can hold the round stock as can a specialized fixture for round stock. Clean the table with compressed air and a sanding stone before setting either down and hand tighten the vise or fixture using T-bolts.

2. Place an indicator on the spindle to make sure that the vise or fixture is straight before tightening it with a wrench. Lower the spindle so that the indicator tip is touching the front flat surface of the vise or fixture. Turn the Y axis traverse wheel enough so that the needle on the dial moves about one half of a revolution in the clockwise position. Turn the bezel so that the needle is on the zero of the dial.

3. Move the indicator back and forth using the X axis traverse wheel to make sure that the vise or fixture is straight. Tap the vise or fixture on either side to line it up so that the needle stays at zero along the front. Tighten the two T-bolts with a wrench and recheck the indicator to make sure that the vise or fixture has not moved.

4. Raise the indicator out of the way of the vise or fixture and place the round stock inside. Place the thickest area of the round stock below the vise jaws or the round stock will slide upwards when pressure is applied. Place the round stock straight as possible if it needs to be sticking straight up for machining.

5. Use the indicator to see if the round stock is straight by placing its tip on one side of it toward the bottom. Move the table so that the indicator dial moves about one half of a revolution and reset the dial to zero. Move the spindle up to the top and notice the movement of the needle. If the needle moves up or down, you will need to carefully tap the round stock and recheck with the indicator until it reads zero from the bottom to the top.

6. Continue the machining process as you would if the material was not round. The mill can cut round stock just like any other type, it takes a bit longer to set it up properly.

References

• American Machine Tools: How to Use a Milling Machine