CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($)	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) [Abstract]
Net sales	$ 60,883,148	$ 59,444,997
Cost of products sold	(47,074,105)	(44,723,521)
Gross margin	13,809,043	14,721,476
Product development expense	(2,239,776)	(1,389,229)
Selling and administrative expenses	(8,398,265)	(9,160,360)
Restructuring costs	(836,694)	0
Operating profit	2,334,308	4,171,887
Interest expense	(292,540)	(296,330)
Other income	13,925	218,731
Income before income taxes	2,055,693	4,094,288
Income taxes	484,733	994,093
Net income	$ 1,570,960	$ 3,100,195
Earnings per Share:
Basic (in dollars per share)	$ 0.25	$ 0.49
Diluted (in dollars per share)	0.25	0.49
Cash dividends per share: (in dollars per share)	$ 0.11	$ 0.11