drillmaster

To become an excellent drillmaster means simply that you have mastered a detail.

As a mathematical instructor I imagine Wrigley was a good drillmaster rather than an inspiring teacher.

They were getting very tired of the drill, and in the humor to nag and balk the drillmaster.

Another calls Grant a great drillmaster, exhibiting him as the teacher of his own generals.

He was the drillmaster of the American Revolution, but he was also its greatest student of the human mind and heart.