In stock



SKU: 16285

Quick Overview

The DRX-3 Prescription mechanical balance features the famous torsion mechanism. The Torsion Balance is entirely manufactured in the United States with highest quality parts. All components of the torsion balance are manufactured from highest grade metals such as brass, and stainless steel. Unique torsion bands deliver 0.002g (2mg) sensitivity with a 60g weighing capacity. The DRX-3 meets or exceeds all the specifications and tolerances for a Class III prescription balance as defined in NBS Handbook 44, DRX-3.

Features and Functions

The fundamental parts of the balance are shown above. Around three metal frames are taut special alloy bands to which the upper and lower beam bars of the balance are firmly clamped. The center frame or truss is rigidly attached to the stand or base.The dial mechanism consists of a special alloy calibrated spiral spring, one end of which is attached to the hub of the dial and the other end to the upper beam bar. Rotating the spiral spring shaft applies a torque to the upper beam bar and is equivalent to adding weight to the right side of the mechanism. The construction of the dial mechanism permits the changing of weight as rapidly or as slowly as desired, with no stress or strain on the mechanism.Thus, the entire mechanism is one piece without any loose parts to wear out or cause faulty operation. No loose parts means the mechanism is permanently adjusted, because the lack of movement of parts (one over the other) assures the user that the initial accuracy and sensitivity remain constant for the life of the balance.The absence of a knife edge fulcrum along with the sliding weight and graduated beam make possible a sensitive balance, independent of wear and unaffected by dust or dirt.
No knife edge fulcrum to wear down or become dull. High sensitivity. Initial sensitivity remains constant. Practically one piece. No loose parts means .balance is permanently adjusted. No bearings to accumulate dust or dirt. Will not become sluggish. Lasting adjustment and accuracy Service free.
A theoretically perfect fulcrum - that is, movement about an axis without friction -has been achieved in the TORSION Balance. By means of adjustable poise weight, the center of gravity of the balance is accurately positioned above the center of rotation. The position of the center of gravity determines the sensitivity of the balance. When inequality of weight is established in the two pans, the beam tips in the direction of the greater weight. The force of gravity always acts in a direction opposite to the torsional resistance. The action of the balance as it oscillates is limited to the slight torsional twist of taut metal bands. There is no friction here because there is no movement of one part over another. This operation is illustrated in Figures 1 and 2.A balance using the TORSION principle is exceptionally quick acting and sensitive to the smallest differences in weight. Because of the one-piece nature of the construction and the absence of wear, once the balance is in adjustment, it remains so as long as it functions. Dusty and dirty atmospheres abrade and deteriorate the knife edges of a conventional balance and cause inaccuracies and loss of sensitivity. The TORSION balance has no such knife edge fulcrums; accordingly, dusty and dirty atmospheres have no effect on the operation or accuracy of the balance. It is this fact which has made the TORSION Balance ideal for both laboratory and industrial use. The accuracy and sensitivity of a TORSION Balance are permanent with its life limited only by the normal wear and tear to which any accurate instrument is subjected. The unique construction of a TORSION Balance results in a balance requiring practically no service.
A cobalt, chromium, nickel alloy with constant torsional properties over a wide temperature range. This alloy also offers extra strength and corrosion resistance.
Extra height permits weighing with the lid down. Plexiglass offers strength with good visibility of pan and index.
Highly polished and corrosion resistant.
One piece metal case has overlapping plate glass top. Complete protection against dust and chemical seepage.
Non-binding; under the case, so chemicals cannot drop into the threads and cause corrosion.
Speeds up weighing by eliminating unnecessary swings of the pointer.
Insures level of balance from front to rear.


Sensitivity1/32 grain (2 mg)
Sensitivity Requirement0.1 grain (6.5 mg)
DialGraduated with double graduations 0.2 grains to 15 grains and 0.1 gram to 1 gram
pansStainless Steel 3 1/8 in.
ArrestPasitive Acting, non-corroding
DampingMagnetic damping for fast weighing
CaseMetal case with corrosion- resistant gray finish. Overlapping black glass plate hinged plexiglass lid 2 - in. high
Dimensions (base)11 - in. x 6 in. x 8 in.
Net Weight11 lbs.
Shipping Weight13 lbs.