There are many things you need to look for and sometimes even experienced collectors or repairman have a hard time trying to determine the type or age of a pickup. The older Fender pickups usually use a .197″ diameter magnets with much of the pits and roughness still left from the sand casting. The magnets usually have one end chamfered that helps direct the magnets through the flatwork without tearing much of the material away and it helps keep the flatwork tighter around the magnets. I very seldom see an old pickup that is bowed or flared because the flatwork became loose.

Pickups made during the mid-60s have magnets that have been ground to a .187″ diameter or 3/16″. The outer surface is much smoother and thus began the period when the bobbins started to bow and flair. Winding had to have precise tension or the ends of the bobbin would flair and cause a distorted coil. The mid-60s magnets had a smoother and less raw looking surface. The mid-60s magnets had a smoother edge and eventually the grinding on the magnets ended.

During the 70s, the raw cut sharp edged magnets were back in production still with the .187″ diameter. At times the Fender Stratocaster bobbins had staggered poles and some had flat poles flush with the plastic pickup cover. You need to carefully look at the various types of pickups and learn as much about the differences as you can. The early flat work till around March ’64 used black vulcanized fibre for the bottoms of most Fender single coil pickups.

During the transition a light gray vulcanized fibre was used and near the 70s a darker vulcanized fibre was used and with the resurgence of the older Fender models and designs being put back in production with an assertive effort to use black vulcanized fibre for the bottom of all Fender re-issues. It may be a small detail but an important one that adds to the confusion to all the various models of pickups on the market.