Drilling

Technique to drill some very accurate holes quite a distance from each other in printing press side frames using a line boring technique.
What I did was centre a shaft in the far bore using a tapered cone and position the near side in a outboard mounted flange bearing. The cone was then replace by an outboard mounted flange bearing. The shaft was permitted to slide laterally in the bearing bores while being driven.
A boring head was mounted to the rotating shaft.

Accuracy of +/- .001" is attainable on the enlarged bore of and in alignment to each other.