Statements of Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011
Income Statement [Abstract]
Net sales	$ 7,661,946	$ 7,005,795	$ 23,921,627	$ 19,613,467
Cost of sales	5,257,556	4,958,639	17,333,569	14,290,980
Gross profit	2,404,390	2,047,156	6,588,058	5,322,487
Selling, general and administrative expenses	663,625	663,544	2,097,317	2,100,027
Operating income	1,740,765	1,383,612	4,490,741	3,222,460
Other income (expense)
Interest income	13,926	13,616	37,396	43,925
Other	7,492	13,048	23,594	97,734
[NonoperatingIncomeExpense]	21,418	26,664	60,990	141,659
Income before income taxes	1,762,183	1,410,276	4,551,731	3,364,119
Provision for income taxes	499,320	398,245	1,291,101	948,802
Net income	$ 1,262,863	$ 1,012,031	$ 3,260,630	$ 2,415,317
Net income per share:
Basic	$ 0.58	$ 0.47	$ 1.50	$ 1.12
Diluted	$ 0.58	$ 0.46	$ 1.48	$ 1.11
Weighted average number of shares outstanding:
Basic	2,174,640	2,157,427	2,170,466	2,150,330
Diluted	2,196,366	2,181,559	2,197,677	2,173,518
Dividends per share:	$ 0.225	$ 0.225	$ 1.675	$ 1.675