Gy-Roll standard adjustable centre heads should be set in the following manner:
• The turrets are rotated to bring the spindles to the required centre distance or pitch circle diameter.
• In cases where a particular spindle setting is frequently required spindle positioners can be provided for quickly locating the spindles in their relative positions.
• When setting the spindle centre distance the head can also be turned relative to the drill unit adaptor. This adjustment may be necessary in order to line up spindles with the other holes to be drilled and tapped.