CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended
	Jul. 31, 2017	Jul. 31, 2016
CONSOLIDATED STATEMENTS OF OPERATIONS
Net sales	$ 4,529,000	$ 4,091,000
Cost of goods sold	3,273,000	2,555,000
Gross profit	1,256,000	1,536,000
Operating expenses:
Engineering	266,000	207,000
Selling, general and administrative	1,286,000	1,112,000
Operating expenses	1,552,000	1,319,000
Earnings (loss) from operations	(296,000)	217,000
Other expense:
Interest expense, net	11,000	6,000
Earnings (loss) before provision (credit) for income taxes	(307,000)	211,000
Provision (benefit) for income taxes	(114,000)	86,000
Net earnings (loss)	$ (193,000)	$ 125,000
Basic earnings (loss) per share	$ (0.04)	$ 0.02