Broaching internal splines - GIF

[Toolmaker51]

There are two motions for broaches; push, which is usually vertical being manual or powered, and pull, also either direction. often depends on physical part size and then the feature itself. A big pattern needs a long broach; and limits vertical machines quickly.
Like key-slotters, many parts require absolute minimal fixturing on a vertical, part drops onto a mandrel/ arbor.