by Jon Elvrum
I make humidors and jewelry boxes, and I need to finish sand the surface where the lid and box meet (which must be flat). The boxes are constructed of 3/4" material, and the lids have 3/4" matching lips. How can I sand these surfaces quickly, easily, and at a minimal cost in a production environment?
I presume the material is a mildly exotic hardwood such as mahogany or Sapele. Many boxes I have seen are, but some are also of cedar, and there are serious differences in the problems each presents.
The harder woods will benefit first from a sequence of grits from 100 (if the wood is mildly rough) to 180 before stain. I prefer silicon carbide to alum oxide because the mineral breaks up sharper and results in a longer cutting life. This produces a generally smoother cut. With the cedar I would start grit sequences at 120 and stop at 220.
There are other questions to be asked: Is this to be stained or lacquered? If so, the machine used to sand any hand detailing should be a random orbital type.
There are also a variety of handheld straight line sanders (used mostly for table tops in the furniture industry). These are usually air-powered and have a larger base to minimize operator tendency to "rock" them.
A wide-belt sander can, if quantities justify, greatly reduce sanding time. If sanding is required following the assembly of the boxes, a stroke sander with a long belt and a sliding feedtable are invaluable.
There is no simple, cheap way to do "fine woodworking" well. We all know this, but continue to look for a silver bullet.
Where labor is unskilled the value of good machinery deepens. Sequence grits on abrasives usually skip one grade between applications (i.e. 80-120-180 is a fairly standard mix). Refine from your experience to achieve the best results. If material arrives clean, you can start with a higher grit. Where machining is clean, you can often step two grits, say from 100 to 180. These are all adjustable based on your situation.
Jon Elvrum, Director of Distribution and Sales at Ritter Manufacturing in Antioch California, is also a well known author and consultant to the cabinetmaking industry. He has written numerous articles on the 32mm cabinetmaking system and production woodworking in general.