Statements of Comprehensive Income - USD ($)	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Net sales	$ 6,068,684	$ 6,279,436
Cost of sales	4,724,936	4,311,116
Gross profit	1,343,748	1,968,320
Selling, general and administrative expenses	772,667	749,650
Operating income	571,081	1,218,670
Other income
Interest income	12,021	7,453
Other	7,002	17,988
Total other income	19,023	25,441
Income before provision for income taxes	590,104	1,244,111
Provision for income taxes	169,279	365,581
Net income	420,825	878,530
Other comprehensive income, net of tax:
Unrealized (loss) gain on investment securities	(686)	1,779
Total comprehensive income	$ 420,139	$ 880,309
Net income per share:
Basic	$ 0.18	$ 0.38
Diluted	$ 0.18	$ 0.38
Weighted average number of shares outstanding:
Basic	2,303,062	2,284,124
Diluted	2,318,986	2,303,805
Dividends per share:	$ 0.25	$ 0.25