Statements of Comprehensive Income (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Net sales	$ 7,286,674	$ 7,303,109	$ 13,210,493	$ 15,640,508
Cost of sales	5,806,526	5,786,874	10,593,997	13,131,339
Gross profit	1,480,148	1,516,235	2,616,496	2,509,169
Selling, general and administrative expenses	1,249,742	1,295,687	2,333,954	2,305,231
Operating income	230,406	220,548	282,542	203,938
Other income
Interest income	33,915	42,376	66,076	94,775
Other	4,849	10,985	20,177	34,657
Total other income	38,764	53,361	86,253	129,432
Income before provision for income taxes	269,170	273,909	368,795	333,370
Provision for income taxes	40,206	56,151	58,055	53,940
Net income	228,964	217,758	310,740	279,430
Other comprehensive income, net of tax:
Unrealized (loss) gain on investment securities	(355)	907	(158)	2,254
Total comprehensive income	$ 228,609	$ 218,665	$ 310,582	$ 281,684
Net income per share:
Basic	$ 0.10	$ 0.09	$ 0.13	$ 0.12
Diluted	$ 0.10	$ 0.09	$ 0.13	$ 0.12
Weighted average number of shares outstanding:
Basic	2,391,643	2,370,948	2,389,526	2,365,220
Diluted	2,395,020	2,393,933	2,395,638	2,388,002
Dividends per share:	$ 0.25	$ 0.25	$ 0.50	$ 1.50