Tuning Balance-Beam Scales For Precision and Repeatability

While many folks enjoy the convenience of an electronic powder scale/dispenser such as the RCBS Chargemaster, some hand-loaders still prefer to use a traditional balance beam. Balance beam scales are simple, compact, and don’t suffer from electronic “glitches”. Moreover, even if you use a digital dispenser at home, when you’re doing load development at the range, a balance-beam scale may be more convenient. A scale doesn’t require electrical power, so you don’t need to bring battery packs or string long power cables. Just bring some kind of box to shelter your beam scale from the wind.

While designs like the RCBS 10-10 are decent performers as built, they can be made much more precise (and repeatable), by “tuning” of key parts. Forum member Scott Parker (aka SParker) optimizes a variety of popular beam scales, including the Ohaus 10-10 (USA-made model), RCBS 10-10 (USA-made model), RCBS 5-10, Lyman M5, Lyman D5, and others. You send Scott your scale, he tunes the key components, tests for precision and repeatability, and ships it back to you. The price is very affordable (under $85.00).

Scott tells us: “I have tuned several 10-10s. They all have turned out very sensitive, consistent and hold linearity like a dream. If only they came that way from the factory. The sensitivity after tuning is such that one kernel of powder registers a poise beam deflection. For repeatability, I remove the pan and replace it for the zero 10 times. The zero line and the poise beam balance line must coincide for each of those 10 tries. I then set the poises to read 250.0 grains. I remove and replace the pan 10 times with the calibration weight. For linearity, the poise beam balance line and the zero line should coincide within the line width. This is roughly one half a kernel of powder. For repeatability, the poise beam balance line must return to that same balance point ten times. I then adjust the poises back to zero and recheck the zero. I have a master’s degree in chemistry, thus I am very familiar with laboratory balances. Email me at vld223 [at] yahoo.com or give me a call at (661) 364-1199.”

The video above, created by British shooter Mark (aka 1967spud), shows a 10-10 beam scale that has been “tuned” by Scott Parker. In the video, you can see that the 10-10 scale is now sensitive to one (1) kernel of powder. Mark also demonstrates the’s scale’s repeatability by lifting and replacing a pan multiple times. You can contact Mark via his website, www.1967spud.com. To enquire about balance-beam scale tuning, call Scott Parker at (661) 364-1199, or send email to: vld223 [at] Yahoo.com.

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Tags: Beam Scale, Chargemaster, OHaus Scale, RCBS 10-10, Scott Parker, Tuning