Segment Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Segment Reporting Information [Abstract]
Revenues, sales to unaffiliated customers	$ 61,439,929	$ 60,860,852	$ 122,323,077	$ 120,305,849
Operating Profit	2,959,293	4,388,506	5,293,601	8,560,393
Interest expense	(261,618)	(312,060)	(554,158)	(608,390)
Other income	586,823	225,769	600,748	444,500
Income before income taxes	3,284,498	4,302,215	5,340,191	8,396,503
Operating Segments [Member] | Industrial Hardware [Member]
Segment Reporting Information [Abstract]
Revenues, sales to unaffiliated customers	37,490,953	35,853,583	75,894,296	72,410,627
Operating Profit	747,415	2,518,086	2,015,552	5,284,529
Operating Segments [Member] | Security Products [Member]
Segment Reporting Information [Abstract]
Revenues, sales to unaffiliated customers	16,502,698	17,888,028	31,185,702	33,007,356
Operating Profit	1,902,547	1,664,041	2,875,435	2,649,180
Operating Segments [Member] | Metal Products [Member]
Segment Reporting Information [Abstract]
Revenues, sales to unaffiliated customers	7,446,278	7,119,241	15,243,079	14,887,866
Operating Profit	$ 309,331	$ 206,379	$ 402,614	$ 626,684