1.75. The GB1096 flat key resembles a semi-circle, which can move within the keyway to accommodate the shape of the hub keyway bottom. It is commonly used for connecting conical shaft ends and in situations where the connecting workload is not heavy. For instance, a conical shaft head can drive a standard A-type belt wheel by connecting with a semi-circular key.

2. Common flat keys are widely used due to their simple structure, easy assembly and disassembly, and good neutrality, making them suitable for high-speed operations, applications with varying loads, and those subject to impacts.

3. Hook head wedges are primarily used for tight key connections. After assembly, due to the slope's influence, the 75.GB1096 flat key causes the shaft and its components to be skewed and eccentric, making it unsuitable for high-precision connections.