Condensed Income Statements (Unaudited) - USD ($)	3 Months Ended
	Jul. 31, 2025	Jul. 31, 2024
Income Statement [Abstract]
Net Sales	$ 5,898,000	$ 5,780,000
Less: Cost of Goods Sold	(2,875,000)	(2,835,000)
Gross Profit	3,023,000	2,945,000
Operating Expenses:
General and Administrative	389,000	337,000
Sales	802,000	807,000
Engineering	24,000	27,000
Total Operating Expenses	1,215,000	1,171,000
Income From Operations	1,808,000	1,774,000
Other Income (Expense)
Other	67,000	2,000
Interest Expense		(1,000)
Dividend and Interest Income	352,000	317,000
Unrealized Gain on Equity Securities	2,381,000	1,346,000
(Loss) on Sale of Assets	(30,000)	(2,000)
Gain on Sale of Investments	145,000	213,000
Total Other Income (Expense)	2,915,000	1,875,000
Income Before Provisions for Income Taxes	4,723,000	3,649,000
Provisions for Income Taxes
Current Expense	479,000	705,000
Deferred tax expense	452,000	239,000
Total Income Tax Expense	931,000	944,000
Net Income	$ 3,792,000	$ 2,705,000
Basic Earnings Per Share of Common Stock	$ 0.78	$ 0.55
Diluted Earnings Per Share of Common Stock	$ 0.77	$ 0.55
Weighted Average Number of Common Shares Outstanding	4,892,032	4,896,730
Weighted Average Number of Shares Outstanding (Diluted)	4,912,532	4,917,230