Balance Sheets (Parenthetical) - USD ($)	Mar. 31, 2018	Jun. 30, 2017
Statement of Financial Position [Abstract]
Trade accounts receivable, allowance	$ 3,000	$ 3,000
Advance payments of costs related to contracts in process	$ 577,714	$ 1,366,504
Common stock, par value	$ 0.3333	$ 0.3333
Common stock, shares authorized	10,000,000	10,000,000
Common stock, shares issued	3,029,874	3,029,874
Common stock, shares outstanding	2,375,923	2,371,321
Unearned ESOP, shares	33,125	45,000
Treasury stock, shares	653,951	658,553