the EDITOR'S column
High Form
T R I P L E B E A M BALANCE
L.T. Hallett, Editor
ί τ A SEMINAR on mass measure•f*- ment held by the Mass and Scale Section of the National Bureau of Standards, 50 representa tives of apparatus manufacturers and standardization laboratories re viewed the areas of responsibilityrelative to NBS calibration serv ices, and discussed measurement problems of concern to the Bureau and to the users and makers of measuring equipment. The Bureau is responsible for calibrating mass standards in terms of the national prototype standard of mass; those who use the stand ards are responsible for transferring the inherent accuracy in the stand ards to meet the needs of science and industry. Paul E. Pontius, Chief of the NBS Mass and Scale Section pointed out several factors to be considered in setting the ac curacy requirements of a particular mass measurement: performance of the equipment, experience of the operator, weighing procedure, and reliability of the reference standard used. Mr. Pontius explained the two types of mass calibration avail able. The Scientific Reference Standard Calibration, for which a certificate of calibration is issued by the Bureau, requires that weights be of one-piece design and meet certain criteria as to fabricat ing material and surface finish. The Laboratory Reference Stand ard Calibration, for which a test re port is issued, has less rigid require ments and most calibrations done at the Bureau fall into this cate gory. H. Haig Russell in charge of the large-scale testing program of the Bureau talked on derived mass values for weights and other values. He stated that the validity of such values requires proper documenta tion of every calibration or test
• High Sensitivity • Stainless Steel Capacity: 111 grams ( w i t h extra w e i g h t 2 0 1 g.) Sensitive to 0 . 0 1 g r a m Includes adjustable platform for specific g r a v i t y determinations PAT. N O . 1872465
No. 4 0 3 0
ONE-PIECE BEAM (PATENTED)
4030.
TRIPLE Form
ELECTROPOLISHED SURFACES
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4030C.
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REVERSE ETCHED SCALES POSITIVE-SETTING WEIGHT
SLIDING
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THE WELCH SCIENTIFIC COMPANY ESTABLISHED 1880 1 5 1 5 S e d g w i c k Street, D e p t . A - 1 , C h i c a g o 1 0 , Illinois, U . S . A . Manufacturers of Scientific Instruments Laboratory Apparatus
HYDRAULIC PRESSES IDEAL FOR FORMING KBr PELLETS FORMING PELLETS FOR X-RAY AND OTHER SPECTROSCOPIC ANALYSIS* RAPID HANDWHEEL ADJUSTMENT OF VERTICAL PLATEN OPENING UNIVERSAL USE FOR RESEARCH, CONTROL TESTING APPLICABLE FOR CERAMIC AND POWDER METAL PRESSING
Shown
Available in 30 and 50 ton sizes. Accessories for temperature, pressure, extrusion, test ing units, etc. for all models.
WRITE FOR BULLETIN
in
Insert
• 20 ton capacity hydraulic press . Guided moving 9" χ 9° platen • Even pressure distribution for uniform den sity . Accurate alignment in operation • Rugged 3 & 4 column construction • 22" maximum vertical opening, adjustable . Self-contained, bench operated
ENGINEERING & MFG. CO. DEPT. A , ROUTE 4 6 , CALDWELL, N. J. Telephone
*For b e t t e r results use Loomis 1 VA " precision x - r a y p e l l e t d i e .
CA 6 - 8 6 6 0
Circle No. 72 on Readers' Service Card VOL
34
NO
11
OCTOBER 1 9 6 2
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