A belt sander comes in different sizes and a small belt sander can be mounted on the bench. Is a belt grinder worth the cost.

How To Build A Belt Sander With A Bench Grinder
Bench grinder vs belt sander. Its not really intended to be an apples to apples comparison. There are disc sanders in the stationary belt sanders. Been looking into a little bench grinder or maybe a freestanding beltdisk sander. Belt has many options. Bench senders are needed to be mounted on the desk to sand the material. It needs to be fixed steadily to a workbench or any other kind of mount.
Difference between bench grinders and belt sanders the bench grinder is designed to sharpen specific items. It is capable of grinding away rough edges smoothly on items like drill bits scissors knives and chisels. Here we tip the hat to the belt sander. The sander can be moved onto the material that is mounted on the bench or the material is moved on the sander belt. The bench grinder may be good for the initial rough work and get the basic shape of the knife. Lets put it to the test against 2 bench grinders.
Beltdisk sander ive found myself needing to grind steel a lot lately but i cant keep turning the hand held belt sander upside down and using it as a flat surface. Its a 100 grinder vs a 1000 belt grinder. Bench is stuck to a few grits belt has many plus small wheel and platen or slack belt work can not be done on a bench grinder. Of course it will depend on the metal you are using to make your knife. Bench grinder is restricted to only one size of contact wheel. But the belt sander can do the fine tuning and really smooth out the metal.
There is no speed control on the bench grinder they are not the same machines.