The subject of geared machine orientation is an interesting one that continues to pop up in luthierie circles, and it deserves a bit of attention.

From Orville Gibson's first instruments, and well through the heralded period of the Loar-signed Master Model instruments of the 1920s, the Gibson company installed geared machines on mandolins, mandolas, and guitars so that the worm gear was below the round gear (A). In this orientation, the string's tension would pull the top of the post toward the tailpiece (B) and in so doing, it would also tend to pull the round gear away from the worm gear. Musicians complained about "slippage" in which they would turn the knob and nothing would happen, until all of a sudden, the post would turn and change the tuning. To counter this problem, in the early 1930s, Gibson engineers decided to invert the machines (thus the term "inverted tuners") so that the worm gear was on the top (C). In this configuration, when the string pulled against the top of the post, the round gear would be pulled into the worm gear to prevent slippage.

This change masked the real problem, but didn't really fix it. While the round gear would be forced to mesh more tightly with the worm gear so that the round gear had no choice but to turn when the worm gear turned, it didn't help to make the machines tune more easily. The real culprit was in the post eyelets and the tight fitting post holes used at the time (D). After a short period of usage, the thin eyelets would be pressed into the peghead wood and, coupled with wear, would soon have the post rubbing against, and causing friction with the wood. So, when the knob would be turned - especially when tuning a string down - the friction would prevent the post from moving immediately until it either slipped or was forced to move when driven further by the worm gear. So, inverting the machines didn't help the post-hole friction problem. In fact, inverting the machines changed the positions of the post and knobs and gave the pegheads a completely different look.

The key to smooth turning machines is to have the post bear on the bushing and on the machine strip (E) - not against the peghead wood.

The first step in getting smooth tuning machines is to have accurately drilled post holes. These holes should be perpendicular to the back of the peghead (this means drilling from the front of the peghead, not from the back as some suggest). The holes should be equally spaced (typically 29/32" apart), and all four holes in a perfectly straight line. Once the holes are drilled, push the machines in from the back, use masking tape as a depth gauge on a drill bit, and drill the five holes for the wood screws, and screw the wood screws in place to ensure everything fits properly. Then, remove the screws and machines and drill the post holes all the way through to the size of the bushings. Do not test fit the bushings; there is a good possibility that removing them will cause some tear-out in the peghead veneer.

With the screw holes located and drilled, when you re-attach the machines once the instrument is finished, the posts will end up dead-center in the post holes and the posts will only bear against the bushings and the machine's back plate. And, they will turn smooth as butter.

Controlling dust is a key focus in our shop. Aside from the fact that shop dust is harmful to breathe, it makes a messy shop, and in many processes it gets in the way of our work and makes it difficult to see what we are cutting.

To help blow dust away, we've devised a 6' length of thin 1/4˝ tubing with an air valve and quick-disconnect fitting that connects into our compressed air system. At the other end of the tubing, we fitted an 8˝ length of brass tubing that is crimped down to a very narrow passage. With this set up, we can plug the tubing into our air system and attach the thin tubing to either the band saw or to a router, adjust the valve for moderate flow, and blow the dust away from the cutting line.

This is especially helpful when routing for inlays. Not only does the blower pipe keep the chips free and provide good visibility, but it also serves to keep the cutter bit cooler.

When working at the bandsaw and cutting items like mahogany block sets that make a lot of dust, we also capture a great deal of the dust that blows off the saw's table by collecting it into a wide-mouth dust collection pick up system positioned right at the back edge of the band saw table.

Note that even though Kali is using the air system (taped on to the Dremel tool) to blow dust away when routing for inlays on this peghead, she is still wearing a dust mask. While the dust is being blown away from her work, it is still present in the environment.