Flat Bit
From DT Online
Flat Bits (aka Spade Bits) are often used with a Power Drill for many DIY tasks.
They are available in a range of sizes, commonly between 8mm and 32mm diameter, easily sharpened with a file and are relatively inexpensive, making them very suitable for most on-site Joinery work.
They are suitable for Counterboring holes, to receive bolt heads for example, but Auger Bits would be preferable for drilling deep holes since Flat Bits can tend to wander.
Safety Point! They are suitable also for use in a Drill Press but great care must be taken to ensure there is no hair or loose clothing which could easily be picked up by these fast revolving drills.
Note: Most wood bits will cause splitting if an attempt is made to drill straight through the material. Best practice is to clamp a backing piece of scrap wood to the reverse side of the piece being drilled (they are difficult to relocate and can grab if the normal practice is adopted of drilling from one side until the tip emerges on the reverse then turning the wood around to complete drilling from the other side).