a rod or tube the end of which is set with black diamonds; - used for perforating hard substances, esp. for boring in rock.
See under Diamond.
See also: Diamond, Drill
diamond drill
diamond drill
[′dī·mənd ‚dril] (design engineering) A drilling machine with a hollow, diamond-set bit for boring rock and yielding continuous and columnar rock samples.
diamond drill
In exploratory drilling, a rotary drill having a coring bit which is studded with black diamonds.