Summary of Significant Accounting Policies (Details Textual)	12 Months Ended
	Jun. 30, 2018 USD ($) shares	Jun. 30, 2017 USD ($) shares	Jun. 30, 2016 USD ($) shares
Advertising Expense	$ 2,000	$ 5,550	$ 15,699
FIFO Inventory Amount	2,376,537	2,472,188
Decreases In Cost Of Goods Sold	242,885	90,510	86,698
Inventory Valuation Reserves	$ 1,619,417	1,597,648
Entity Number of Employees	202
Collective Bargaining Period Expiry Date	May 31, 2021
Health Care Insurance Accrued Liabilities	$ 180,000	215,000
Research and Development Expense	472,077	410,458	463,902
Share-based Compensation	2,830	$ 2,491	$ 2,946
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 1,000
Weighted Average Number of Shares Outstanding, Basic and Diluted | shares	4,013,537	4,013,537	4,013,537
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount	$ 1,000	$ 1,000	$ 1,000
Warranty Service [Member]
Revenue Recognition, Multiple-deliverable Arrangements, Determination of Selling Price, Amount	299,034	136,606	$ 89,895
Revenue Recognition Multiple Deliverable Arrangements Determination Of Liability Amount	$ 150,000	$ 100,000
Minimum [Member]
Property, Plant and Equipment, Useful Life	3 years
Maximum [Member]
Property, Plant and Equipment, Useful Life	35 years
Collective Bargaining Agreement [Member]
Entity Number of Employees	115