LYMAN D-7
gunpowder
precision reloading scale

Lyman gunpowder scale

This is a very precise weighing scale to weigh the right amount of gunpowder in case you want to refill, charge, or load, a bullet or cartridge for your firearm. This precision reloading scale is made by Lyman from Middletown in Connecticut, USA. I (yet) don't know how old this gunpowder scale is. One can still buy a photocopy of the operating instructions on eBay. Old handbooks of Lyman are available on the internet with detailed information about the proper amount of gunpowder to charge different types of ammo, cartridges and shotshells for different brands of guns and pistols. The weighing beam pivots at a knive edge bearing. The scale is very precise and sensitive. The housing of the scale has a rotary knob to operate an excenter. A vertical rod rests at this excenter. By rotating the knob clockwise, the excenter brings the rod upwards and this lifts the knife-shaped axis of the weighing arm from its bearing pans. This prevents wear of the knive edge bearing when the scale is not in use but is still moved by wind or drafts. The here presented gunpowder scale weighs in grains. The weighing range is 505 grains.

back of the scale

At the left 500 grains, plus 5 grains at the right, makes a total of 505 grains. 1 grain = 0.06479891 gram, rounded to 64.799 milligrams, or about 0.065 grams. 7000 grains = 1 pound = 16 ounces. And so 1 grain is equal to 0.002285714 oz. At the left the weighing arm has a scale of 500 grains with stripes every 5 grains. At the right the weighing arm has a scale of 5 grains, here every stripe is equal to one tenth of a grain. There exists also a metrical version weighing in parts of grams. The left scale ranges from 0 to 32.50 grams, every stripe represents 0.25 grams. The entire scale at the right of the knife edge bearing is 0.25 grams in total, and every stripe is 0.005 grams (five thousandth of a gram!). The weighing range of this grams version is therefore 32.75 grams. Before the actual weighing one starts to adjust the scale to zero at the left by turning the screw under the housing of the scale. Ensure that the adjustable poises, the heavy and the light weight, are as much as possible at the right on the weighing arm. To weigh a certain amount of gunpowder, first place the heavy poise to the left just below, almost at, the wanted number of grains, and use the light weight to fine tune the wanted number of grains. Now fill the pan with just enough gunpowder until the pointer of the weighing arm indicates zero. Now you have the wanted amount of gunpowder in grains. Two magnets are inside the aluminum housing at the left on both sides of the gap, they are damping the movement of the scale beam by exercising a force on the small copper part. (Search term: 'Eddy current brake'or 'magnetic damping'). The precision powder scale of Lee Precision also has magnetic damping, see the Lee powder scale.
Below some more pictures of this precise Lyman gunpowder scale.

operating instructions of the gunpowder scale

left the scale up to 500 grains, subdivided per 5 grains right a scale up to 5 grains, subdivided per tenth grain

operating instructions of the gunpowder scale

the partly disassembled scale

from above, the magnetic damper is near the gap left

bottom of the scale house at the left the zero leveling screw and at the right the excenter and its knob

left scale up to 32.50 grams, subdivided per 0.25 grams right a scale up to 0.25 grams, subdivided per 0.005 grams

the gunpowder scale seems to be made for right handed people

[move pointer over picture] place a weight in the pan and get a renewed equilibrium by moving the counterweights

the gunpowder scale seems to be made for right handed people

the suspension arm of the pan bends too easily	the pan for the gunpowder	suspension of the pan
the weighing arm points exactly at zero	the heavy poise at 125 grains	the light poise at 21 x 0.1 = 2.1 grains
the zero leveling screw at the left of the scale house	the name LYMAN is also at the top of the heavy poise	the name LYMAN is molded at the scale house
control knob to rotate the excenter and lift the beam and its knife edge axis	the vertical rod, just visible, has lifted the knife edge axis out of its pans	the excenter in the scale house