A rather optimistic gentleman arrived with a Presto MRC-16 disk recording lathe, inquiring about the possibility of repairing the broken suspension and making a cutter head bracket from scratch. He then asked about the possibility of figuring out some way in which lead-in, lead-out, and track mark spirals could be cut on this machine, which was originally intended as a very basic machine, with no provision for spirals, not even a hand crank. Then came the really ambitious part: He would ideally like to be able to adjust the pitch and if possible, control the lathe through his computer!

One glance at the steampunk aesthetic of the manufacturer's name plate and the overall state of this primitive machine would have been enough to deter the average engineer, in fear that there might be something potentially radioactive hiding within...

A simple yet effective movement which has seen many decades of regular use, appears under the lid of this dial indicator.

It was once able to indicate accurately in 0.01 mm graduations, through a gear train driven by a rack on one side of the spindle.

Presto disk recording lathes are often still in active use nowadays, nearly 80 years after they originally left the factory in New York. Let us have a closer look at what keeps them spinning!

For some reason, the people involved with the manufacturing of vinyl records are rather stoic types. The rare occasion when they are in a talkative mood, they mostly talk about the manufacturing process and equipment. They are not often talking about what happens after the records have been manufactured, the actual reproduction of these records, for pleasure or for the most critical step of manufacturing: Quality control.

What follows is the story of the restoration, modification, assembly, calibration and testing, of some components, which, if used properly, can result in a highly accurate phonograph disk reproduction system.

In 2015, J. I. Agnew started developing a high-end cutting amplifier for disk mastering systems, to be used with motional feedback stereophonic cutter heads. During this process, he investigated the design and implementation problems of such transducers in great detail. As usual, he documented his progress, which evolved into an engineering report, titled "An Investigation of Motional Feedback Disk Recording System Design", which was accepted for publication in the November 2018 issue of the Journal of the Audio Engineering Society, following the customary peer review process.