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                                                                   EXHIBIT 10.15

                            AMENDMENT TO EMPLOYMENT
                               AGREEMENT BETWEEN
                                    EMPLOYEE
                                      AND
                           SMITH INTERNATIONAL, INC.


         This Amendment to Employment Agreement is entered into this 16th day
of October, 1989 and is by and between the employee executing this agreement on
the last page hereof  ("EMPLOYEE")  and Smith International,  Inc. ("COMPANY").

         WHEREAS, EMPLOYEE AND COMPANY entered into an Employment Agreement on
December 10, 1987  (the "Employment Agreement") which sets forth EMPLOYEE'S
term of employment with COMPANY; and

         WHEREAS, the Employment Agreement did not address or provide any
protection for EMPLOYEE or COMPANY in the event of a Change in Control of
COMPANY; and

         WHEREAS, should COMPANY receive any proposal from a third person
concerning a possible business combination with, or acquisition of equity
securities of, COMPANY, the Board of Directors of COMPANY believes it
imperative that COMPANY be able to rely upon EMPLOYEE's advice as to the best
interest of COMPANY and its shareholders without concern that EMPLOYEE might be
distracted by the personal uncertainties and risks created by such a proposal.

         NOW, THEREFORE, EMPLOYEE and the COMPANY hereby agree as follows:

         1.      In the event a third person begins a tender or exchange offer,
                 circulates a proxy to shareholders, or takes other steps to
                 effect a Change of Control (as defined in Section 11 hereof)
                 of COMPANY, EMPLOYEE agrees that he will not voluntarily leave
                 the employ of COMPANY, and will render the services
                 contemplated in the Employment Agreement, until the third
                 person has abandoned or terminated his efforts to effect a
                 Change of Control or until a Change  of Control has occurred.

         2.      In the event EMPLOYEE's employment with the COMPANY (including
                 its subsidiaries) is involuntarily terminated (as defined in
                 Section 8 hereof), other than as a consequence of his death or
                 disability, or of his retirement at or after his normal
                 retirement date under COMPANY's pension or other retirement
                 plans, within one and one-half (1 1/2) years after a Change of
                 Control of COMPANY (a "Covered Termination"), each of the
                 following payments shall be made by COMPANY to EMPLOYEE not
                 later than thirty (30) days after the date of such covered
                 Termination:

                 (a)      Base Salary.  An amount in cash equal to three (3)
                          times the amount of EMPLOYEE's base salary in effect
                          on his date of Covered




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                          Termination.  Any payments made hereunder are in lieu
                          of any lump sum payment of base salary required under
                          the Employment Agreement as a result of the
                          termination of EMPLOYEE pursuant to Section 4.3 of
                          the Employment Agreement.

                 (b)      Bonus.  An amount in cash equal to the amount of
                          EMPLOYEE's Target Incentive Level for an Award under
                          COMPANY's Long Term Incentive Compensation Plan as
                          in effect on his date of Covered Termination.

                 (c)      401(k) Plan.  An amount in cash equal to the amount
                          contributed by COMPANY under the Smith International,
                          Inc. 401(k) Retirement Plan (the "401(k) Plan") to
                          EMPLOYEES's "Company Contribution Account," as such
                          term is defined in the 401(k) Plan, for the year
                          ending immediately prior to the Change in Control.

                 (d)      Perquisites.   An amount in cash equal to the
                          perquisite  amount  provided  in  the  Executive
                          Perquisite Program in effect on EMPLOYEE's date of
                          Covered  Termination.   Any  payments  made hereunder
                          are in lieu of any lump sum payment of perquisites
                          required under the Employment Agreement as a result
                          of the termination of EMPLOYEE pursuant to Section
                          4.3 of the Employment Agreement.

3.       COMPANY agrees that for the period beginning on the date of EMPLOYEE's
         Covered Termination and ending on the first to occur of (i) the date
         of EMPLOYEE's reemployment or (ii) the last day of the twelfth (12th)
         month following the date of EMPLOYEE's Covered Termination,  COMPANY
         shall provide medical and dental insurance, life insurance, accidental
         death and dismemberment  insurance  and disability protection  no less
         favorable to EMPLOYEE (including with respect to any costs borne by
         EMPLOYEE) than the better of (a) the coverage provided by COMPANY
         immediately prior to the Change of Control or (b) the coverage
         provided by COMPANY immediately prior to EMPLOYEE's date of Covered
         Termination.

4.       Without in any way limiting any pre-existing agreements between
         COMPANY and EMPLOYEE, in the event of a Covered Termination,  COMPANY
         will  assist  EMPLOYEE with  executive  outplacement,  will  provide
         office space  from which  EMPLOYEE may  conduct  employment efforts,
         and secretarial assistance, for a period of up to one year at no cost
         to EMPLOYEE and will reimburse EMPLOYEE for the out-of-pocket costs
         and expenses (including, without limitation, the reasonable fees of
         any placement agencies employed by EMPLOYEE and travel expenses,  but
         excluding all relocation expenses) incurred by EMPLOYEE in seeking
         other employment following any involuntary termination up to a maximum
         amount of $12,000.

5.       Stock Options.  Upon a Change in Control, all stock options become
         fully vested and exercisable immediately.  In the event of a Covered
         Termination, COMPANY shall pay to EMPLOYEE, in respect of each option
         to purchase common stock of the Company and any related stock
         appreciation right  ("SAR")  granted to EMPLOYEE





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         under  COMPANY's  1989  Long-Term  Incentive Compensation Plan,  1982
         Stock Option Plan or 1971 Stock Option Plan (the "Stock Option Plans")
         that is then outstanding (and that has not been exercised) an amount
         in cash equal to the excess, if any, of the higher of (a) the Closing
         Price per share of COMPANY's common stock on the EMPLOYEE's
         termination date or (b) the highest per share price actually paid in
         connection with any Change of Control (such higher amount being
         hereinafter referred to as "Fair Market Value") over the exercise
         price, multiplied by the total  number of  shares of COMPANY's common
         stock subject to such option.   Such payment shall be in consideration
         of a cancellation of any rights which EMPLOYEE may have in said stock
         options and SARs.

6.       Unrelated Stock Appreciation Rights (SARs).  In the event of a Covered
         Termination, the COMPANY shall pay to EMPLOYEE,  in  respect of each
         then outstanding unrelated SAR held by EMPLOYEE, an amount  in cash
         equal to the amount by which the Fair Market Value of each share of
         COMPANY's common stock subject to the SAR exceeds the exercise price
         thereof, multiplied by the number of shares of COMPANY's common stock
         subject to such SAR.  Such payment shall be in consideration of a
         cancellation of any rights which EMPLOYEE may have in said SARs.

7.       Stock Grants.  Upon a Change in Control, all stock grants become fully
         vested and exercisable immediately.  In the event of a Covered
         Termination, the COMPANY shall pay to EMPLOYEE, in respect of each
         then outstanding stock grant granted to EMPLOYEE under the Stock
         Option Plans, an amount in cash equal to the Fair Market Value of each
         share of COMPANY's common stock subject to the stock grant, multiplied
         by the number of shares of COMPANY's common stock subject to such
         stock grant.  Such payment shall be in consideration of a cancellation
         of any rights which EMPLOYEE may have in said Stock Grants.

8.       Involuntary Termination.  For purpose of this agreement, EMPLOYEE's
         employment with COMPANY (including its subsidiaries) shall be deemed
         to have been involuntarily terminated by COMPANY if (a)  EMPLOYEE's
         employment is terminated by COMPANY for a reason other than for cause
         (which for purposes of this Agreement shall mean EMPLOYEE's gross
         negligence, habitual neglect or willful misconduct in performance of
         the duties and services required of him pursuant to the Employment
         Agreement or EMPLOYEE's final conviction of a felony or of a
         misdemeanor involving moral turpitude) or (b) EMPLOYEE terminates his
         employment with COMPANY within sixty (60) days of the occurrence of
         one or more of the following events: (i) a substantial adverse
         alteration in the nature or status of EMPLOYEE's responsibilities from
         those in effect immediately prior to the Change in Control (other than
         any such alteration primarily attributable to the fact that COMPANY
         may no longer be a public company); (ii) the assignment to EMPLOYEE of
         any duties inconsistent with his status as an executive officer of
         COMPANY; (iii) a reduction by COMPANY in EMPLOYEE'S annual base salary
         as in effect on the date hereof or as the same may be increased from
         time to time except for across-the-board salary reductions similarly
         affecting all executives of COMPANY and all executives of any person
         in control of COMPANY; (iv) COMPANY 5 requiring





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         EMPLOYEE to be permanently based anywhere other than the continental
         United States except for required travel on COMPANY's business to an
         extent substantially consistent with EMPLOYEE's present business
         travel obligations; (v) the failure by COMPANY to continue in effect
         compensation plans that, in the aggregate, provide EMPLOYEE with
         benefits not materially less favorable than those provided to EMPLOYEE
         immediately prior to the Change in Control  under  COMPANY's  pension,
         profit  sharing, bonus,  incentive, life insurance, health, accident,
         disability and other employee benefit plans, programs or arrangements
         (other than stock-based compensation plans, programs or arrangements);
         or (vi) the taking of any action by COMPANY that would materially
         adversely affect the physical conditions existing at the time of the
         Change in Control in or under which EMPLOYEE performs his employment
         duties;  provided, however, that a termination of employment by
         EMPLOYEE pursuant to clause (ii), (iii), (iv), (v) or (vi) of this
         Section 8 shall not fail to constitute an involuntary termination
         within the meaning of this Section 8 merely because the event set
         forth in any such clause is primarily attributable to the fact that
         COMPANY is no longer a public company.

9.       Section 7 to the Employment Agreement is hereby revised to insert a
         new subsection (d) as follows:

         (d)     Following the occurrence of a Covered Termination, the
                 Employment Period shall be defined as the period of time in
                 which EMPLOYEE is employed by the COMPANY.

10.      Upon a Change in Control, the provisions of Section 7 relating to
         Non-Competition shall not be construed to prohibit  EMPLOYEE  from
         seeking  or  continuing employment with any third person who may
         acquire 50% or more of  the outstanding common shares of the COMPANY.


11.      Definition of Change of Control.  For the purpose of this Amendment, a
         "Change of Control" shall be deemed to have taken place if:  (i) a
         third person, including a "group" as defined in Section 13(d)(3) of
         the Securities Exchange Act of 1934, acquires shares of the COMPANY
         having 50% or more of the total number of votes that may be cast for
         the election of Directors of the Company; (ii) as the result of any
         cash tender or exchange offer, merger or other business combination
         (a "Transaction"),  the persons who were Directors of the COMPANY
         before the Transaction shall cease to constitute a majority of the
         Board of Directors of the COMPANY or any successor to the COMPANY; or
         (iii) the stockholders of the COMPANY approve an agreement to sell or
         otherwise dispose of all or substantially all of the Company's assets
         (including a plan of liquidation).

12.      Relation to Other Benefit Plans.   Except for the specific references
         above to the Employment Agreement nothing in this Amendment shall be
         deemed to alter or be in lieu of any entitlements due EMPLOYEE under
         the benefit plans or policies of COMPANY in existence on the date
         hereof.  In the event any benefit plan or policy of COMPANY shall
         provide for earlier vesting or payment to EMPLOYEE (e.g.,





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         stock options, stock appreciation rights or stock grants) than set
         forth herein then the terms of the plan or policy shall govern.

13.      Successors.   This Amendment shall be binding upon and inure to the
         benefit of the EMPLOYEE and his estate, and the COMPANY and its
         successors or assigns, but neither this Amendment nor any rights
         arising hereunder may be assigned or pledged by the EMPLOYEE.

IN WITNESS WHEREOF, the parties have executed this Amendment as of the day and
year first above written.


SMITH INTERNATIONAL, INC.                      EMPLOYEE:



By: /s/ DOUGLAS L. ROCK                        /s/ D. BARRY HEPPENSTALL
    ------------------------                   ---------------------------
        Douglas L. Rock                            D. Barry Heppenstall





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