Statements of Income (USD $)	12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Income Statement [Abstract]
Net sales	$ 32,037,357	$ 29,499,504
Cost of sales	23,217,194	21,293,305
Gross profit	8,820,163	8,206,199
Selling, general and administrative expenses	2,828,409	2,905,916
Operating income	5,991,754	5,300,283
Other income
Interest and dividend income	49,354	56,154
Other	40,348	25,105
Total other income	89,702	81,259
Income before income taxes	6,081,456	5,381,542
Provision for income taxes	1,691,188	1,524,005
Net income	$ 4,390,268	$ 3,857,537
Net income per share:
Basic	$ 2.02	$ 1.79
Diluted	$ 1.99	$ 1.77
Weighted average number of shares outstanding:
Basic	2,172,589	2,151,443
Diluted	2,203,060	2,176,299