Belt Sander

A belt sander is a machine in which an abrasive belt, spinning between two pulleys, removes material from the workpiece. It's one of the main tools of the shaping stage in a pipe workshop: it's used to rough out the shape of a drilled body (stummel), to remove excess from a mouthpiece, and in some workshops to prepare briar blocks before turning. Which of these jobs falls to which machine depends on how much the belt itself can flex; for this reason, the type of abrasive is considered more decisive than the machine's brand. For where shaping fits in the overall production flow, see the how a pipe is made entry.

Belt and Abrasive Selection

The weight of the cloth on the belt's backing directly determines what can be done with it. In the abrasives industry, cloth backings are referred to by letter; the finest and most flexible of these is "J" weight. X and Y weights are stiffer and longer-lasting but reluctant to conform to a curved surface. In setups guided by finger pressure, J weight is therefore what's sought. Moving from rough shaping to a clean surface, using 120, 180, 220, and 320 grits in sequence is considered a customary progression. Belts from long-established manufacturers like Klingspor, Norton, Hermes, and 3M are the benchmark for this work; the same makers' economy product lines don't always give the same result.

Benchtop Combination Machines

The most common off-the-shelf machine seen in workshops is the combination type, carrying a 1 x 42-inch belt on one side and an 8-inch disc on the other; Delta's 31-340 model is a well-known example in this class, and its table can be tilted to allow angled work. On such a machine, the real work happens on the belt. Removing the backing plate behind it frees the belt, making it easier to conform to convex surfaces. Taking down excess vulcanite on a hand-cut mouthpiece and roughly forming the button can also be done here; for how mouthpiece materials behave, see the mouthpiece materials entry.

The same machine's disc has limited use for body shaping. Because the disc sits close to the table surface, there's no room to turn the body around and change angle; the guard in front of it also gets in the way. For this reason, most makers prefer to mount the shaping disc on the lathe spindle, or on a motor dedicated solely to that purpose.

Squaring Blocks

There's one job the combination machine's disc is unquestionably good for: squaring blocks before drilling. The table is set to exactly 90° to the disc face with a square, the fence is zeroed, and the block's faces are cleaned up so they're perpendicular to each other. A block with square faces sits centered in a self-centering chuck no matter which face it's mounted from. This is one of the details that determines whether the smoke channel exits dead-center at the base of the bowl; for more, see the drilling on the lathe entry.

Flexible-Belt Workshop Rigs

Especially among European makers, machines running a long belt stretched between two pulleys, unsupported from behind, are common; the workshops of Tom Eltang and Rainer Barbi are cited as well-known examples of this arrangement. Because the unsupported belt can be pushed with the fingers into whatever curve is needed, it allows access to tight transitions like the bowl-to-shank join; the longer the belt, the more flexibility it offers. In return, it demands skill, which is why it's noted to require a longer learning period than an off-the-shelf machine.

Two points stand out on this type of machine. The first is static charge: friction between the belt, the pulleys, and the workpiece builds up a considerable charge, which is why it's recommended that at least one of the pulleys be made of a conductive material and the rig be grounded. Discharge of that buildup is considered a risk both for shock and for igniting fine airborne dust. The second is speed; records suggest the motor running around 800-1000 rpm is appropriate, since anything higher burns the fingers guiding the belt. Because the job doesn't need high torque, a small motor is considered sufficient; speed can be reduced with a step pulley if needed.