Complex sentence: This is in contrast with the traditional square mounts of prior art, which require all four sides to be machined in order to achieve precise right angles at all corners whereas machining of round plates only requires a simple lathe operation.
Split into simpler sentences: This is in contrast with the traditional square mounts of prior art, which require all four sides to be machined in order to achieve precise right angles at all corners. Machining of round plates only requires a simple lathe operation.