Two pits and two grooves square handle electric hammer drill, five pits long hexagonal electric hammer drill, five pits Bosch electric hammer drill. What's their difference?

The pit shape of the drill is related to the chuck structure of the electric hammer!

Generally speaking, the chuck can only match the shapes of the corresponding pits and grooves. As for what shape is completely designed by the electric hammer manufacturer, each family is different and cannot be used universally. Personally, I have long felt that we should unify the standards and save trouble!

Generally, square handle four pits are the most common, and the well-known domestic brand "Dragon Brand" electric hammer is used. Later, many electric hammers imitating the dragon brand used this design, which was the most widely used and common in the market.

Two pits and two grooves are Bosch's patents, and the five pits you mentioned are also Bosch's special drills.