PRODUCT DRILL HOLE MAKING (GSR JERMAN)
Drilling is a separation process to create round holes into a material through chip removal. A distinction is made between blind hole drillings and through hole drillings. A core hole must be bored to cut a thread into the hole. Core holes have specific sizes which correspond to the taps. You can find these sizes in each tap table as it’s absolutely necessary to stick to it.
Twist drills have a side rake angle(also called twist angle) of 27°, apoint angle of 118° or 135° and acylindrical shank. The ? nish “TypeN” is suitable for normal chippingmaterials. A distinction is made between roll forged and fullyground twist drills.
When producing the roll forgeddrill the blank is heated and formedintoa spiral.When producing the fully grounddrillthe spiralis ground out of the fully hardenedmaterial.Fora betterdifferentiation of the varioustypesthe following surfaces are assigned to the different drills: