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 20 9 0.28

30 8 0.28

40 7 0.28

50 6 0.28

60 5 0.28

70 4 0.28

80 3 0.28

Reinforced Plastics 30 29 0.77

40 22 0.78

50 16 0.75

60 10 0.78

70 5 0.75

	Reading Range	Number of Readings	Average Variance of
Homogeneous Material	20	9	0.28
30	8	0.28
40	7	0.28
50	6	0.28
60	5	0.28
70	4	0.28
80	3	0.28
Reinforced Plastics	30	29	0.77
40	22	0.78
50	16	0.75
60	10	0.78
70	5	0.75

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

35 23 32

36 23 33

37 24 37

38 24 40

39 25 43

40 25 25 45

41 26 26 47

42 26 27 49

43 27 27 52

44 27 28 54

45 27 20 56

46 28 30 58

47 29 32 24 61

48 30 33 25 63

49 31 34 28 64

50 32 35 30 66

51 33 36 33 68

52 34 38 36 70

53 35 39 39 29 72

54 37 41 42 33 73

55 38 42 44 38 75

56 39 44 46 40 76

57 40 45 48 43 78

58 42 47 51 47 80

59 44 48 53 49 81

60 45 49 55 51 83

61 47 51 57 54 84

62 48 53 59 56 86

63 50 55 62 58 88

64 52 57 64 61 89

64 54 58 65 63 90

66 55 60 67 65 91

67 58 62 69 67 92

934-1 Brinnell Vickers Rockwell

B E F H

68 60 64 71 69 94

69 62 67 73 71 95

70 64 69 18 74 73 96

71 67 72 19 76 75 98

72 69 74 28 77 77 99

73 71 76 33 79 79 100

74 73 81 39 81 81 101

75 76 85 45 83 83 102

76 80 88 48 84 84 103

77 84 92 52 86 86 104

78 87 95 56 88 87 105

79 90 99 60 89 88 106

80 94 103 63 90 89 107

81 97 108 65 91 90 108

82 100 111 69 92 91 108

83 105 116 72 94 92 109

84 109 122 75 95 93 109

85 113 127 77 96 94 110

86 117 133 80 97 95 111

87 122 137 83 98 96 111

88 126 142 86 99 97 112

89 131 144 89 100 97 112

90 135 91 101 98 113

91 139 102 99 113

92 145 103 100

93 103 101

94 104 101

95 104 102

96 105 102

97 106 103

98 107

99 108

100 108

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

GYZJ-935 & GYZJ-936 Type D Durameter

GYZJ-935 GYZJ-936

4 64 52

6 65

8 53

10

12 66 54

14

16 67 55

18 56

20 68

22 57

24 58

26 69

28 59

GYZJ-935 & GYZJ-936 Shore (Type) D Durameter

GYZJ-935 GYZJ-936

30 70 60

32

34 71 61

36 62

38 72 63

40 73 64

42

44 74 65

46 66

48 75 67

50 68

52 76 69

54 77 70

56 71

GYZJ-935 & GYZJ-936 Shore (Type) D Durameter

GYZJ-935 GYZJ-936

58 78 72

60 79 73

62 74

64 80 75

66 81 76

68 82 77

70 78

72 83 79

74 84 80

76 85 81

78 83

80 86 84

82 87 85

84 88 86

86 89 87

88 n/a 89

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

934-1	Brinnell	Vickers	Rockwell
934-1	Brinnell	Vickers	B	E	F	H
35		23				32
36		23				33
37		24				37
38		24				40
39		25				43
40	25	25				45
41	26	26				47
42	26	27				49
43	27	27				52
44	27	28				54
45	27	20				56
46	28	30				58
47	29	32		24		61
48	30	33		25		63
49	31	34		28		64
50	32	35		30		66
51	33	36		33		68
52	34	38		36		70
53	35	39		39	29	72
54	37	41		42	33	73
55	38	42		44	38	75
56	39	44		46	40	76
57	40	45		48	43	78
58	42	47		51	47	80
59	44	48		53	49	81
60	45	49		55	51	83
61	47	51		57	54	84
62	48	53		59	56	86
63	50	55		62	58	88
64	52	57		64	61	89
64	54	58		65	63	90
66	55	60		67	65	91
67	58	62		69	67	92
934-1	Brinnell	Vickers	Rockwell
934-1	Brinnell	Vickers	B	E	F	H
68	60	64		71	69	94
69	62	67		73	71	95
70	64	69	18	74	73	96
71	67	72	19	76	75	98
72	69	74	28	77	77	99
73	71	76	33	79	79	100
74	73	81	39	81	81	101
75	76	85	45	83	83	102
76	80	88	48	84	84	103
77	84	92	52	86	86	104
78	87	95	56	88	87	105
79	90	99	60	89	88	106
80	94	103	63	90	89	107
81	97	108	65	91	90	108
82	100	111	69	92	91	108
83	105	116	72	94	92	109
84	109	122	75	95	93	109
85	113	127	77	96	94	110
86	117	133	80	97	95	111
87	122	137	83	98	96	111
88	126	142	86	99	97	112
89	131	144	89	100	97	112
90	135		91	101	98	113
91	139			102	99	113
92	145			103	100
93				103	101
94				104	101
95				104	102
96				105	102
97				106	103
98				107
99				108
100				108

GYZJ-935 & GYZJ-936	Type D Durameter
GYZJ-935 & GYZJ-936	GYZJ-935	GYZJ-936
4	64	52
6	65	52
8		53
10		53
12	66	54
14	66	54
16	67	55
18	67	56
20	68	56
22		57
24		58
26	69	58
28	69	59
GYZJ-935 & GYZJ-936	Shore (Type) D Durameter
GYZJ-935 & GYZJ-936	GYZJ-935	GYZJ-936
30	70	60
32	70	60
34	71	61
36	71	62
38	72	63
40	73	64
42	73	64
44	74	65
46	74	66
48	75	67
50	75	68
52	76	69
54	77	70
56	77	71
GYZJ-935 & GYZJ-936	Shore (Type) D Durameter
GYZJ-935 & GYZJ-936	GYZJ-935	GYZJ-936
58	78	72
60	79	73
62	79	74
64	80	75
66	81	76
68	82	77
70	82	78
72	83	79
74	84	80
76	85	81
78	85	83
80	86	84
82	87	85
84	88	86
86	89	87
88	n/a	89

Operation

Typical Readings of Aluminum Alloys

Approximate Conversion Curves for GYZJ-934-1

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

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

Approximate Conversion Curves
for GYZJ-934-1

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

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