Condensed Income Statements (Unaudited) - USD ($)	3 Months Ended
	Jul. 31, 2024	Jul. 31, 2023
Income Statement [Abstract]
Net Sales	$ 5,780,000	$ 4,728,000
Less: Cost of Goods Sold	(2,835,000)	(2,462,000)
Gross Profit	2,945,000	2,266,000
Operating Expenses:
General and Administrative	337,000	368,000
Sales	807,000	689,000
Engineering	27,000	22,000
Total Operating Expenses	1,171,000	1,079,000
Income From Operations	1,774,000	1,187,000
Other Income (Expense)
Other	2,000	8,000
Interest Expense	(1,000)
Dividend and Interest Income	317,000	241,000
Unrealized Gain on Equity Securities	1,346,000	1,634,000
Gain (Loss) on Sale of Assets	(2,000)	8,000
Gain (Loss) on Sale of Investments	213,000	(118,000)
Total Other Income (Expense)	1,875,000	1,773,000
Income Before Provisions for Income Taxes	3,649,000	2,960,000
Provisions for Income Taxes
Current Expense	705,000	310,000
Deferred tax (benefit) expense	239,000	276,000
Total Income Tax Expense	944,000	586,000
Net Income	$ 2,705,000	$ 2,374,000
Basic Earnings Per Share of Common Stock	$ 0.55	$ 0.48
Diluted Earnings Per Share of Common Stock	$ 0.55	$ 0.48
Weighted Average Number of Common Shares Outstanding	4,896,730	4,928,974
Weighted Average Number of Shares Outstanding (Diluted)	4,917,230	4,949,474