Low Cost DIY Rod Weighing Setup

67Dart273 said
I'm certainly no expert on rod weighing specifics but it seems to me that having so much weight into the jig itself would cause inaccuracy simply because it starts to become more and more of the total combined rod and jig weight. I'd think a "skeleton" jig for lack of better word that is much lighter would then allow the small change in rod weight (between rods, etc) to then be a larger overall change in comparison.

"Extremes" Let's say the jig is about equal to or double the rod weight. You could reach a point where a change in rod weight that you might desire correction would be so small in comparison to the total weight that the resolution of the scale simply will not show it up

On the other hand if you could get the jig down to say, 1/8 of the rod weight, then any change obviously becomes a larger percentage change

I give you guys credit.........You are always thinkin' !!!

It's not about the total weight of the plate in this design... it is about how well the symmetry of the plates layout is maintained.

Tnx Del,
If the jig's symmetrical design is maintained in the construction, then:

the jig weight on each end will be identical
there will be no leverage of uneven jig weights from one end effecting the other end
thus, all the weight of the jig will correctly zero out at both end of the rod.

The above can be shown via 1st level static mechanics. (Free body diagrams and all that stuff....)

Now if the jig gets heavy, then inaccuracies in layout and build can lead to assymetrical weights in the jig plate, and that can lead to biases in the weighing. If that happened, the big and small end weight totals would show a bias above or below the total rod weight. So, yes, you are better off keeping the plate light, so that any layout inaccuracies have very little effect on the measurement results.

FYI, this total jig weight is 173 grams, including the bottle cap 'slider' on the scale. That is 24% of the lighter stock SBM rods, and around 28% of the lightweight aftermarket I-beam rods.