Statements of Comprehensive Income (Loss) (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Net sales	$ 6,962,065	$ 7,286,674	$ 14,227,580	$ 13,210,493
Cost of sales	6,248,604	5,806,526	12,386,745	10,593,997
Gross profit	713,461	1,480,148	1,840,835	2,616,496
Selling, general and administrative expenses	945,478	1,249,742	1,860,104	2,333,954
Operating (loss) income	(232,017)	230,406	(19,269)	282,542
Other income
Interest income	1,753	33,915	16,970	66,076
Other	13,734	4,849	16,861	20,177
Total other income	15,487	38,764	33,831	86,253
(Loss) income before provision for income taxes	(216,530)	269,170	14,562	368,795
(Benefit) provision for income taxes	(35,524)	40,206	5,745	58,055
Net (loss) income	(181,006)	228,964	8,817	310,740
Other comprehensive (loss) income, net of tax:
Unrealized gain (loss) on investment securities	2,712	(355)	1,038	(158)
Total comprehensive (loss) income	$ (178,294)	$ 228,609	$ 9,855	$ 310,582
Net (loss) income per share:
Basic	$ (0.08)	$ 0.10	$ 0.00	$ 0.13
Diluted	$ (0.08)	$ 0.10	$ 0.00	$ 0.13
Weighted average number of shares outstanding:
Basic	2,402,665	2,391,643	2,402,649	2,389,526
Diluted	2,402,665	2,395,020	2,404,043	2,395,638
Dividends per share:	$ 0.25	$ 0.25	$ 0.50	$ 0.50