Low Cost DIY Rod Weighing Setup

Observations on the scales:

· The issue of side-loads throwing off the scale readings is unique to the scale, not to the jig. The tapping on the supporting work surface with each change is to ‘jiggle’ things, and let them move the tiny amount needed to relieve the miniscule side loads that result from even the tiniest movement of the jig or rod vs the scale.

· I have not yet sprung the $$ for a better scale, like the ones from Summit, to see if they are better for this problem. Without a better scale, I can’t separate out the sources of error: the jig itself, my use of the jig, or the cheapo scale.

· IMHO, springing for a good scale is a higher priority than an expensive rod hanging jig.

· The cheapo scales seem to come pretty well calibrated.

· DON”T EVER PUSH THE CAL BUTTON ON THESE SCLAES UNLESS YOU HAVE THE CORRECT CALIBRATION WEIGHTS on hand. If you do, you are hosed!

· As your own calibration source, buy a 1 or 2 cup plastic measuring cup and weigh it with the scale when new. Mark the cup weight on the cup and keep it. If you want to check the scale, then you can:

o Weigh the cup to see if the reading is the same

o Then add cold water with the same burette you use for measuring head chamber volumes. Each cc weighs almost precisely 1 gram per cc, so if you add 100 cc’s of water into the cup, the weight on the scale should go up exactly 100 grams.