Leather Bench Machines
Leather Splitters, Skivers, Rein Rounders, Presses, and String Cutters
Leather splitters are used to thin and level leather. All splitters will level, but some models will also make a tapered skive. The pull through splitters work best on firmer leather such as vegtan and latigo - leathers that have some body to them, There can be some questions about how wide of leather a pull through splitter can do. My general experience and recommendation is that they are good up to three inches of width, Beyond that it can get harder to pull the leather through. The extra blade widths will give you more edge to use before needing to strop or resharpen.
Leather skivers make a tapered skive on the edge of firm leather like vegtan or latigo leather. The skive can be adjusted for width and angle.
Rein rounders are for drawing leather straps and laces through to create a round cross section for straps, handles, and tack.
Lace and String Cutters/Bevellers
Lace and String Cutters/Bevellers - are used to cut and bevel laces and strings for braiding. Most are designed to clamp onto a bench and cut to precise widths and then bevel the laces or strings. Some models also have a built-in splitting or leveling area as well. I don't get these very often.
Crown Splitters are used to cut slits into straps or cut straps to width lengthwise. Examples are cutting ear lits in crown pieces for headstalls or slits into straps for "mystery braids".