Level Developments Precision Engineers Level
By Dennis Davis
Everyone knows (or should know) that it’s important to get your turntable perfectly level. For most vinyl enthusiasts, the inexpensive spirit level is the tool of choice, a short length ‘box (or ‘carpenter’s’) level being the most cost-effective solution: that or any of a host of ‘audiophile’ accessories, often small, ‘bulls eye’ levels. Set the level across the platter and adjust the table until the bubble centers between the two parallel lines (or in the circle) at the center of the level’s vial. Job done! Or maybe not…
A typical box level picked up at your local DIY store generally claims to be accurate, depending on make and model, to somewhere between .3 and 1.0 millimeters. That means it will reflect a down-angle of 0.3 to 1.0mm in a 1m distance. For years I’ve used a 10” box level from Austrian manufacturer Sola for most of my leveling needs. It claims a “measuring tolerance” of .5 mm, is easier to read than most other brands and, truth be told, it is bright red and way prettier than most of the more common levels on the market, so I keep it around for its good looks. This kind of accuracy may well suffice for leveling audio racks and platforms, but it is certainly too crude a tool for leveling a turntable.
A few decades ago, I discovered that there were more sophisticated instruments than your average, generic box level. On the recommendation of an architect audiophile friend, I picked up a machinist’s (sometimes called an engineer’s) level, the Starrett No. 98-6. The Starrett is a heavy cast iron affair with a scale of 12 parallel lines within which to center the bubble, rather than the standard two. The difference in accuracy between a box and machinist’s level is quite significant. Compare this photo of the Sola box level next to the Starrett machinist’s level. The turntable surface was leveled using the box level and the machinist’s level set down next to it. The box spirit bubble appears to be centered, but the Starrett shows that the device is far from level. Clearly, what is sufficiently level to a carpenter is way off center to a machinist. And, yes, if you level the turntable with the machinist’s level, the box level reading still looks centered.
The smaller the scale of the item you are leveling and the greater its operating precision, the more critical the tolerances needed to make it work. Imagine trying to construct a house to the precision of a machinist’s level—the construction time would escalate as would the price, but the house would look and perform the same. A machinist’s level is generally used to level machine tools in a manufacturing shop, where tighter tolerances are required than those used in general construction.
The US built Starrett machinist’s level has a published specification of “accuracy per foot” of .005 inches per foot (or roughly, a genuine 0.3 – 0.4mm/m). That is at least as accurate as the best off-the-shelf box level – and probably significantly more consistent. It costs almost ten times as much as a short box level, but in the realm of audiophile gadgets, we are still talking pocket change. But what’s more important is that when it comes to your turntable, you can HEAR how level it is. Believe me, you need your turntable to be way more level than the timbers in your home, or the lathe in a machine shop.