A belt sander is useful for removing burrs and rough edges from parts. It is composed of a belt coated with abrasive riding about two pulleys. The lower pulley is driven by a motor. The upper pulley follows and allows tension in the belt to be adjusted.
Belt sanders are effective on wood, most metals (aluminum, steel, brass, etc), and some plastics. The small particles generated by the belt sander can be toxic. It's good to use a sander with a vent attached to it and to wear a mask when using the belt sander. Don't use the belt sander on printed circuit boards or fiberglass; they create toxic particles.
When smoothing edges and rounding corners, the part should be supported on
the table of the machine. The part should be moved back and forth to achieve
a better finish and to avoid hot spots on the belt.
To round off the edges of a part, one must hold the part on an angle with
respect to the belt. Be sure that the belt is pointing down into the belt as
demonstrated in the video. If the part is pointing up, the belt could catch
on the part and throw it down into your hand. Note the size of the gap
between the belt and table is wider than the work piece. This is a dangerous
situation. The gap should be adjusted.
Some jobs cannot be done on the large belt sander shown above. For
instance it is impossible to smooth out the faces of an inside corner. For
this task, a smaller machine with a thin belt is appropriate.
As the small belt sander was previously configured, it is difficult to
smooth out convex features without creating facets on the part. This problem
can be alleviated by reconfiguring the machine. The table and platen can be
removed to allow the belt to conform to the shape of your part.