If you're talking about "box" ways versus dovetails, the advantage box
ways have is in rigidity. Big chunks of iron moving at high speeds need
lots of support for a machine to hold 0.00005 positioning tolerances.

Of course the devil is always in the details, so well made dovetails may
actually perform better than poorly-made box ways.

DeepDiver wrote:

I've noticed that some machines (particularly the larger ones) have square
ways instead of dovetail ways. Why is this? Is it simply because square ways
are easier or cheaper to manufacture, or are there other benefits?

Regards,
Michael