General The Proctor Penetrometer is used in method of test for establishing the moisture penetration resistance relations of fine-grained soils as determined by penetration testing. The Model H-4139, Proctor Penetrometer is furnished with these interchangeable needles: (in2 (cm2)) 1 (6.45), 3/4 (4.84), 1/2 (3.22), 1/3 (2.15), 1/5 (1.29), 1/10 (.65), 1/20 (0.32), 1/30 (0.22) and 1/40 (0.16). Replacement needles are available. H-4139 complies with ASTM D1558 for number and sizes of needles required.
