Aligning A Vise on a Mill

[Frank S]

The way I've always done it which achieves suitable results for me is to clamp a long sine bar in my vice, visually sight down the edge of the bar to one of the t slots until it appears close, then use a machinist adjustable tri square by placing the body of the square against the leading face of the mill table slide the blade until it touches the edge of the sine bar next to the vice then move the square to one end or the other of the sine bar check if it touches the bar but not the table, wiggle the vice then set the square to the other end of the bar check again. By using the principal of half of a half of a half the differences from the edge of the sine to the face of the table by adjusting the blade once or twice and wiggling the vice until the 3 distances match the vice will be aligned with the face of the table, tighten the bolts and job done. No need t0 shift the table to the left or to the right, no need of a dial indicator attached to the quill with the whisker touching the fixed face of the vice just a simple straight bar and a tri square It matters not if the vice is mounted near one end or the other or near the center. My 3hp ENCO mill won't know the difference. My table is 30" the travel is less than 20 inches my bar is the same length of the table. As long as the X&Y gibs are correctly adjusted anything milled in the vice along either axis is going to be the exact same as the axis of plane it is milled on