Income Statements - USD ($)	12 Months Ended
	Apr. 30, 2025	Apr. 30, 2024
Income Statement [Abstract]
Net Sales	$ 22,538,000	$ 21,767,000
Less: Cost of Goods Sold	(11,628,000)	(10,926,000)
Gross Profit	10,910,000	10,841,000
Operating Expenses:
General and Administrative	1,442,000	1,492,000
Selling	3,114,000	2,958,000
Engineering	116,000	102,000
Total Operating Expenses	4,672,000	4,552,000
Income From Operations	6,238,000	6,289,000
Other Income (Expense)
Other Income	96,000	37,000
Interest (Expense)	(6,000)
Impairment on Investment in Limited Land Partnership		(38,000)
Dividend and Interest Income	1,410,000	1,116,000
Unrealized Gain (Loss) on Equity Securities	(75,000)	2,771,000
Gain on Sale of Investments	937,000	148,000
Gain on Solar Tax Credit	515,000
(Loss) on Sale of Assets	(2,000)
Total Other Income (Expense)	2,875,000	4,034,000
Income Before Provisions for Income Taxes	9,113,000	10,323,000
Provisions for Income Taxes
Current Expense	2,082,000	2,115,000
Deferred tax expense (benefit)	(102,000)	650,000
Total Income Tax Expense	1,980,000	2,765,000
Net Income	$ 7,133,000	$ 7,558,000
Earnings Per Share of Common Stock
Basic	$ 1.46	$ 1.54
Diluted	$ 1.45	$ 1.53
Weighted Average Number of Common Shares Outstanding (Basic)	4,895,349	4,913,676
Weighted Average Number of Common Shares Outstanding (Diluted)	4,916,544	4,934,176