Condensed Consolidated Statements of Income - USD ($)	3 Months Ended
	Aug. 31, 2020	Aug. 31, 2019
Income Statement [Abstract]
Sales, net	$ 5,759,457	$ 5,708,639
Cost of goods sold	4,204,889	4,025,762
Gross profit	1,554,568	1,682,877
Selling, general and administrative expenses	1,363,203	1,290,531
Operating income	191,365	392,346
Other income, net	9,646	37,231
Income before provision for income taxes	201,011	429,577
Provision for income taxes	25,000	75,000
Net income	$ 176,011	$ 354,577
Basic and diluted earnings per common share	$ 0.05	$ 0.10