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                                                                    Exhibit 3.7


                            ARTICLES OF INCORPORATION

                                       OF

                            F.B.S. SUPPLY CO., INC.


      The undersigned, a citizen of the United States, desiring to form a
corporation for profit, under the General Corporation Act of Ohio Section
1701.01, et seq., Revised Code of Ohio, does hereby certify:


      FIRST:  The name of said corporation shall be F.B.S. SUPPLY CO., INC.

      SECOND:  The place in Ohio where its principal office is to be located is
Industrial Blvd., P.O. Box 1026 E., Wooster, Wayne County, Ohio 44691.

      THIRD:  The purpose or purposes for which it is formed are:

      a.  To engage in the business of buying, selling, leasing, distributing,
      repairing, machining, and threading oil, gas and water well supplies,
      industrial supplies and to do all things necessary and incidental to such
      business;

      b.  To acquire, own, use, convey and otherwise dispose of and deal in real
      property or any interest therein; and to own, construct, operate, manage,
      use or lease, in whole or in part, buildings and other structures;

      c.  To acquire, purchase, own, hold, vote, guarantee, sell, pledge or
      otherwise dispose of and otherwise use and deal in or with shares of
      stock, bonds, mortgages, and other securities and obligations of domestic
      or foreign corporations, associations, partnerships or individuals and the
      direct or indirect obligations of the United States, or of any state,
      territory or dependency thereof or of any foreign government or of any
      governmental subdivision or instrumentality; to act as a general or
      limited partner in partnerships, syndicates and any other form of business
      organization permitted by law;

      d.  To acquire any part or all of the business, including goodwill, of any
      person, firm, association or corporation, whether or not the business is
      similar to that in which the corporation is then engaged, and to conduct
      in the State of Ohio or elsewhere any business acquired, provided such
      business is not prohibited by the laws of the State of Ohio, and

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      e.  To apply for, purchase or otherwise acquire, hold, use, sell or in any
      manner dispose of, lease, assign, mortgage, grant licenses or other rights
      therein, and in any manner deal with letters patent, patent rights,
      licenses, inventions, improvements, processes, copyrights, trade marks and
      trade names.

      Each purpose specified in any clause or paragraph of this Article is an
independent purpose and shall not be limited by reference to or inference from
the terms of any other clause or paragraph of these Articles of Incorporation.

      The corporation reserves the right to substantially change its purposes.
If a change of purpose is authorized by the vote now or hereafter required by
statute, dissenting shareholders shall not have appraisal or payment rights.

      FOURTH:  The maximum number of shares which the corporation is authorized
to have outstanding is Five Hundred (500) which shall be common shares without
par value.

      Shares which are not issued pursuant to subscription taken by
incorporators may be issued or agreed to be issued at any time and from time to
time for such consideration or considerations as may be fixed by the Board of
Directors. Any shares so issued, the consideration for which, as fixed by the
incorporators or by the Board of Directors has been paid or delivered, shall be
fully paid and nonassessable.

      At a meeting for such purpose, notice of which has been given to all
shareholders, the shareholders may adopt a resolution of dissolution and thereby
authorize the dissolution and winding-up of the Corporation upon the affirmative
vote of the holders of shares entitling them to exercies 67% of the voting power
of the corporation on such proposal of dissolution.

      FIFTH:  The minimum amount of capital with which the corporation will
begin business is Five Hundred Dollars ($500.00).

      SIXTH:  Without derogation from any other power to purchase shares of the
Corporation, the Board of Directors may purchase for the account of the
Corporation any issued shares of the corporation to the extent of the surplus
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in the manner permitted by law.

      SEVENTH:   A director shall rot be disqualified from dealing or 
contracting with the Corporation as vendor, borrower, lender, employee, agent,
or otherwise; nor shall any transaction or contract or act of the Corporation be
void or voidable or in any way affected or invalidated by the fact that any
director or any firm of which any director is a member of any corporation of
which any director is a shareholder, director or officer is in any way
interested in such transaction or contract or act, provided the fact that such
director or such firm or such corporation is so interested shall be disclosed or
shall be known to the Board of Directors or such members thereof as shall be
present at any meeting of the Board of Directors at which action upon any such
contract or transaction or act shall be taken; nor shall any such director be
accountable or responsible to the Corporation for or in respect to any such
transaction or contract or act of this corporation or for any gains or profits
realized by him by reason of the fact that he or any firm of which he is a
member or any corporation of which he is a shareholder, director or officer is
interested in such transaction or contract or act; and any such director may be
counted in determining the existence of a quorum at any meeting of the Board of
Directors of the Corporation which shall authorize or take action in respect to
any such contract, or transaction, or act, and may vote to authorize, ratify, or
approve any such contract or transaction or act, with like force and effect as
if he or any firm of which he is a member, or any corporation of which he is a
shareholder, director or officer were not interested in such transaction or
contract or act.

      EIGHT:   Every person who is or has been a director or officer of the
Corporation shall be indemnified by it against expenses and liabilities
reasonably incurred by him in connection with either (1) any action, suit or

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proceeding to which he may be a party defendant, or (2) any claim of liability
asserted against him, by reason of his having been a director or officer of the
Corporation. Without limitation, the term "expenses" shall include any amount
paid or agreed to be paid in satisfaction of a judgment or in settlement of a
judgment or claim or liability other than any amount paid or agreed to be paid
to the Corporation itself. The corporation shall not, however, indemnify any
director or officer in respect to matters as to which he shall be finally
adjudged liable for negligence or misconduct in the performance of his duties as
such director or officer, nor in the case of settlement unless such settlement
shall be found to be in the interest of the corporation (1) by the Court having
jurisdiction of the action, suit or proceeding against such director or officer
or of a suit involving his right to indemnification, or (2) by a majority of the
directors or the corporation then in office other than those involved (whether
or not such majority constitutes a quorum), or, if there are not at least two
directors of the Corporation then in office other than those involved, by
majority of a committee (selected by the Board of Directors) of five or more
shareholders of the Corporation who are not directors or officers, provided that
such indemnity in case of a settlement shall not be allowed by such directors or
committee of shareholders unless it is found by independent legal counsel that
such settlement is reasonable and in the interest of the corporation.

      The foregoing right of indemnification shall be in addition to any other
rights to which any such director or officer may be entitled as a matter of law.

      Each person (including a director or officer of the corporation) who, at
its request, acts as a director or officer of any other corporation, may


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by indemnified by the Corporation to the same extent and subject to the same
conditions that directors and officers of the Corporation are indemnified by the
first paragraph hereof when authorized by a resolution of the Board of Directors
of the Corporation.

      IN WITNESS WHEREOF, I have hereunto subscribed my name, this 14th day of
June, 1979.


                                                         /s/ Frank B. Swindell
                                                         ---------------------
                                                         Frank B. Swindell