I believe everyone knows what kind of drill a straight shank drill bit is, and the fixed shank twist drill bit actually has the same concept as the straight shank twist drill bit. The straight shank twist drill bit has the same blade diameter and shank diameter. It is called a straight shank, and fixed shank means that the blade diameter is different at a certain stage, but the shank diameter is the same, such as the Suzuki twist drill bit with a 1/2 shank fixed shank twist drill, and the OBS alloy drill bit between 0.3-3.175 3.0 shank 3.175 shank fixed shank twist drill bit, the best tool OBS twist drill