No matter what material you’re cutting, getting the blade tension right is one of the keys to quality cuts on the bandsaw. Unfortunately, most bandsaws come with only a rudimentary tension gauge, and while there are plenty of tricks for measuring blade tension indirectly, nothing beats a digital blade tension gauge for repeatable results.
Despite being an aftermarket accessory for his beefy Hitachi CB-75F bandsaw, [Stephen B. Kirby]’s Pi-based tension guide looks like an OEM product. Housed in a sturdy case and sporting a sealed membrane keypad and four-line LCD display, the interface electronics are pretty straightforward. The tricky bit is sensing the amount of tension on the bandsaw blade. For that task, [Stephen] mounted a load cell in place of the original tensioning spring. A few adapters helped that job, and with a little calibration, the gauge is capable of displaying the tension by measuring the force over the cross-sectional area of the current blade.
We really like it when electronics can bring a new level of precision to old-school hardware, whether it’s a simple DRO for a manual lathe or a more accomplished build like [Stephen]’s. Sometimes adding new silicon can make old iron a little easier to use.