Operation

The Impressor is intended for handheld testing of hardness for aluminum and aluminum alloys, soft metals, plastics, fiberglass, rubber and leather. Harder materials cannot be tested with the Impressor. For information on the available models, refer to the current revision of our product guide.

To test a surface, place the indenter point and the leg of the impressor on the same plane of the surface. To insure reading accuracy, make certain that no indentations from previous use are within 1/16th of an inch of the present indenter point position. Readings should not be taken on both sides of the 1/32nd inch-thick test disks. Readings taken on top of old indentations will adversely affect the accuracy of the reading. An ample supply of appropriate test disks should be maintained for these reasons.

Press down firmly, but carefully, on the impressor handle. Observe the indicator, noting the peak reading. For softer materials there will be some falling-off of the reading from the peak value. This is normal and is due to the nature of the materials being tested.

As a general rule, you should increase the number of readings taken as the softness of the materials being tested increases. Refer to the table below for recommended minimal numbers of readings for various materials using the Model GYZJ 934-1. Though specific numbers for Models GYZJ 935 and GYZJ 936 are not included due to correlation difficulties with softer materials, the numbers suggested for reinforced plastics serve as a starting point for softer materials.

The indenter point must always be perpendicular to the surface being tested. To maintain perpendicularity, the leg of the Impressor must be on the same plane as the indenter point, with both flats of the leg touching the same surface. Irregularlyshaped objects to be tested should be mounted in a holding jig to assure that perpendicularity is maintained. For flat objects, a temporary offset of the leg to accommodate the thickness of the part being tested can be obtained by placement of washers of appropriate thickness between the leg and the case of the impressor. Without perpendicularity, accuracy of the reading cannot be assured.

Recommended numbers of readings for Model GYZJ 934-1

Reading Range Number of Readings Average Variance of
Homogeneous Material 2090.28
3080.28
4070.28
5060.28
6050.28
7040.28
8030.28
Reinforced Plastics 30290.77
40220.78
50160.75
60100.78
7050.75

Typical Readings of Aluminum Alloys

Alloy and Temper: 1100-0 3003-0 3003H14 2024-0 5052-0 5052H14 6061T6 2024T3
GYZJ-934-1 Reading: 35 42 56 60 62 75 80 85

Approximate Conversion Curves
for GYZJ-934-1

Approximate Conversion Chart
for GYZJ-934-1 to Brinnell,
Vickers and Rockwell

934-1 Brinnell Vickers Rockwell
B E F H
352332
362333
372437
382440
392543
40252545
41262647
42262749
43272752
44272854
45272056
46283058
4729322461
4830332563
4931342864
5032353066
5133363368
5234383670
533539392972
543741423373
553842443875
563944464076
574045484378
584247514780
594448534981
604549555183
614751575484
624853595686
635055625888
645257646189
645458656390
665560676591
675862696792
934-1 Brinnell Vickers Rockwell
B E F H
686064716994
696267737195
70646918747396
71677219767598
72697428777799
737176337979100
747381398181101
757685458383102
768088488484103
778492528686104
788795568887105
799099608988106
8094103639089107
8197108659190108
82100111699291108
83105116729492109
84109122759593109
85113127779694110
86117133809795111
87122137839896111
88126142869997112
891311448910097112
901359110198113
9113910299113
92145103100
93103101
94104101
95104102
96105102
97106103
98107
99108
100108

Approximate Conversion Chart
for GYZJ-935 and GYZJ-936 to
Type D Durameter

GYZJ-935 & GYZJ-936 Type D Durameter
GYZJ-935GYZJ-936
46452
665
853
10
126654
14
166755
1856
2068
2257
2458
2669
2859
GYZJ-935 & GYZJ-936 Shore (Type) D Durameter
GYZJ-935GYZJ-936
307060
32
347161
3662
387263
407364
42
447465
4666
487567
5068
527669
547770
5671
GYZJ-935 & GYZJ-936 Shore (Type) D Durameter
GYZJ-935GYZJ-936
587872
607973
6274
648075
668176
688277
7078
728379
748480
768581
7883
808684
828785
848886
868987
88n/a89