Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net income	$ 1,455,905	$ 1,678,184
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	943,595	932,500
(Gain) loss from disposal of equipment	17,485	(17,613)
Deferred income taxes	(40,000)	(94,000)
Changes in operating assets and liabilities:
Accounts receivable, net	(232,484)	(450,535)
Inventories	298,422	(401,963)
Other current assets	15,489	(139,946)
Accounts payable	349,057	350,207
Accrued wages and salaries	308,406	462,838
Other accrued expenses	(69,726)	(56,565)
Unearned revenue and customer deposits	158,822	(35,098)
Net cash provided by operating activities	3,204,971	2,228,009
Cash flows from investing activities:
Capital expenditures	(1,339,044)	(1,329,170)
Proceeds from the sale of equipment	4,869	18,700
Proceeds from certificates of deposit	5,560,000	2,639,348
Purchases of certificates of deposit	(5,818,000)	(2,241,000)
Net cash used in investing activities	(1,592,175)	(912,122)
Cash flows from financing activities:
Cash dividends paid	(763,245)	(908,164)
Net cash used in financing activities	(763,245)	(908,164)
Net increase in cash and cash equivalents	849,551	407,723
Cash and cash equivalents at beginning of period	231,252	443,608
Cash and cash equivalents at end of period	1,080,803	851,331
Supplemental schedule of non-cash investing activities:
Capital expenditures in accounts payable	$ 3,073	$ 19,966