Hardness Test Results

Polymers -- Durometer and Rockwell Hardness

Material	Reference hardness	Experimental hardness	% Error
Buna-N Square O-Ring Cord Stock	Shore A: 70-75	77	6%*
Low-Density Polyethylene (LDPE)	Shore D: 42	57	36%
High-Density Polyethylene (HDPE)	Shore D: 68	72	6%
Polypropylene	Shore D: 77	76	1%
PVC Type I	Shore D: 80	82	3%
PVC Type I	Shore D: 89	84	6%
Cast Acrylic	Rockwell M: 93	104	12%

Reference values from McMaster-Carr.
* Compared to middle of reference range.

Metals -- Rockwell Hardness

Material	Reference HRB	Experimental HRB	% Error	Reference UTS (ksi)	Estimated UTS (ksi)	% Error
C11000-H2 Copper	40	39	3%	41.2	not shown	--
A36 HR Steel	67-83	72	4%*	58-80	62	10%*
2024-T4 Aluminum	75	74	0%	68.2	65	5%
C27000-H4 Brass	80	83	0%	74	80	8%
1035 CR Steel	86	87	0%	84.8	84	0%
1045 CR Steel	90	96	1%	95	102	7%

Reference values from MatWeb.
* Compared to middle of reference range.

Metals -- Brinell Hardness

Material	Reference HB	Experimental HB	% Error	Reference UTS (ksi)	Estimated UTS (ksi)	% Error
C11000-H2 Copper	--	71**	--	41.2	not shown	--
A36 HR Steel	119-159	133	4%*	58-80	66	4%*
2024-T4 Aluminum	120	137	14%	68.2	66	3%
C27000-H4 Brass	--	149	--	74	84	14%
1035 Steel	170	181	6%	84.8	88	4%
1045 Steel	187	241	29%	95	98	3%

Reference values from MatWeb.
* Compared to middle of reference range.
** diameter = 0.268" = 6.81 mm; HB = 2(3000) / 10p sqrt(10²-6.81²) = 71.3  (see formula)