EatSmart sent me a review unit of their Precision Digital Scale to see if it was a fit for pinewood derby use. The scale is attractive and lightweight, and runs on two AAA batteries (included). It’s also inexpensive, retailing for just $25 on Amazon.
The scale comes with the required two AAA batteries, a three page instruction manual, and a booklet of weight to calorie conversions. Pinewood, plastic, and tungsten are not listed in the book, so I couldn’t look up how many calories a Derby car has. The whole scale is less than two inches tall and comes in a box about the size of a hardback book.
Operation is simple. There’s an off/off button and a button for changing the unit of measurement displayed on the screen. Pressing the on/off button when the scale displays zero will turn it off. Pressing it when the scale shows a weight will tare it to zero. Pressing the Unit button will toggle between the four supported units of measurements. There’s a very large digital readout, located far enough away from the weighing platform to allow unobstructed viewing, even with a large object on the scale. The readout is capable of displaying in grams, kilograms, ounces, or pounds. Accuracy is 0.05 of an ounce, more than enough for most pinewood uses. The scale features a three minute auto shut-off to preserve the batteries if you forget to turn it off.
The weighing platform on the scale is slightly too small to hold a BSA pinewood car with a standard wheelbase. Placing a car on it causes the wheels to roll off the side. To weigh your car on this, you’ll need to do it without the wheels attached. You can also place a small wooden block on the scale and tare the scale with this block on it, using the block to lift your wheels off the surface of the scale. Since I always add weight to my cars before attaching the wheels (I weigh the wheels separately first), this isn’t a problem for me, but might be an inconvenience for others.
My review copy would occasionally briefly fluctuate 0.05 ounces above and below the actual weight, always returning to and settling on the correct weight again after a moment. This doesn’t make the scale unusable, but does require that you spend a moment looking at the scale to make sure the weight has settled.
The platform size probably prevents this from being used as the official scale at a pinewood derby. This would be a useful scale for personal use and testing, however. The small size means it fits easily in most toolkits, the battery operation allows you to use it anywhere, and the inexpensive price point allows you to have your own scale without breaking the bank. The fact you can measure down to five hundredths of an ounce means you can get your car as close as possible to the magic weight limit, much closer than you can get with a scale reading only tenths of an ounce.