Document:

<PAGE>

                                                                   Exhibit 10.19

          Amendments to the Varco International, Inc. 1990 Stock Option Plan

          WHEREAS,   the Board of Directors of the Corporation deem it desirable
          and in the best interests of the Corporation and its shareholders that
          the Corporation's 1990 Stock Option Plan (the "Plan") be amended in
          certain respects;

          NOW, THEREFORE, BE IT RESOLVED, that paragraph F of Section 6(b) of
          the Plan be, and the same hereby is, amended to read in its entirety
          as follows:

               F.   Other Severance.  In the event an employee's employment with
          Varco and its subsidiaries is terminated for any reason other than as
          set forth in paragraphs D and E above, any Nonstatutory Option which
          he holds may be exercised, to the extent it was exercisable on the
          date of termination of his employment, within such period after the
          date of termination of his employment (not to exceed ninety (90) days)
          as the Committee shall prescribe in his option agreement. For purposes
          of this Paragraph F, an employee's employment shall be deemed to have
          terminated on the earlier of the date his employment terminates or the
          date he receives written notice that his employment is or will be
          terminated. Such Option shall expire upon the expiration of such
          period unless the employee dies prior thereto, in which event he shall
          be deemed to have died on the date his employment terminated;
          provided, however, in no event shall such Option be exercised more
          than ten years from the date such Option was granted.

     and further

          RESOLVED, that paragraph  F of Section 6(c) of the Plan be, and the
          same hereby is, amended to read in its entirety as follows:

               F. Other Severance.  In the event an employee's employment with
          Varco and its subsidiaries is terminated for any reason other than as
          set forth in paragraphs D and E above, any Incentive Stock Option
          which he holds may be exercised, to the extent it was exercisable on
          the date of termination of his employment, within such period after
          the date of termination of his employment (not to exceed ninety (90)
          days) as the Committee shall prescribe in his option agreement. For
          purposes of this Paragraph F, an employee's employment shall be deemed
          to have terminated on the earlier of the date his employment
          terminates or the date he receives written notice that his employment
          is or will be terminated. Such Option shall expire upon the expiration
          of such period unless the employee dies prior thereto, in which event
          he shall be deemed to have died on the date his employment terminated;
          provided, however, in no event shall such Option be exercised more
          than ten years from the date such Option was granted.

          and further

          RESOLVED, that the Compensation Committee of the Board of Directors,
          as the Committee under the Plan, is authorized, in its sole discretion
          and from time to time, to amend any option outstanding under the Plan
          in a manner consistent with the foregoing amendments to the Plan; and

          RESOLVED, that each of the officers of the Corporation be, and he
          hereby is, authorized and directed to perform all acts and to execute
          and deliver all
<PAGE>

          certificates and documents and to take or cause to be taken all other
          action as any such officer may deem necessary or appropriate to carry
          out the foregoing resolutions and to comply with the terms and
          provisions of the Plan.<PAGE>

                                                                   Exhibit 10.20

                 Form of Amendment to Stock Option Agreements

                           VARCO INTERNATIONAL, INC.

                      AMENDMENT TO STOCK OPTION AGREEMENT

     This AMENDMENT TO STOCK OPTION AGREEMENT, dated ___________, is made by and
between VARCO INTERNATIONAL, INC., a California corporation ("Varco") and the
employee executing this Amendment below as Employee (the "Employee").

                             W I T N E S S E T H:

     WHEREAS, the Employee was granted one or more options on or prior to May
13, 1999 (the "Outstanding Options") to purchase shares of Varco's Common Stock
pursuant to Varco's 1990 Stock Option Plan; and

     WHEREAS, the Outstanding Options are evidenced by one or more Stock Option
Agreements (the "Option Agreements") made by Varco for the benefit of the
Employee; and

     WHEREAS, on May 13, 1999, the Board of Directors of Varco approved certain
amendments to the Plan and authorized the Compensation Committee (the
"Committee") of the Board of Directors of Varco, in its sole discretion, to
amend outstanding options consistent with the amendments to the Plan; and

     WHEREAS, the Compensation Committee of the Board of Directors of Varco has
approved an amendment to the Outstanding Options and authorized the execution
and delivery of amendments to the Outstanding Options incorporating such
amendment; and

     NOW, THEREFORE, the parties hereto hereby agree as follows:

     1.   Each of the Outstanding Option Agreements is hereby amended as
follows:

          The provisions of each Outstanding Option Agreement providing for the
     termination of the option upon the termination of the Employee's employment
     with Varco and its subsidiaries in cases other than the Employee's death or
     retirement under certain circumstances, wherever located and however
     designated or numbered, are hereby amended to read in their entirety as
     follows:
<PAGE>

          "Subject to the provisions hereof relating to the termination of the
     Option upon the death of the Employee or the retirement of the Employee in
     specified circumstances, on the 90th day following the termination of the
     employment of Employee with Varco and its subsidiaries for any reason
     whatsoever, including, without limitation, any termination caused by
     Employee's quitting, resigning or having been discharged.  For the purposes
     of this paragraph an Employee's employment shall be deemed to have
     terminated at the earlier of the date his/her employment actually
     terminates or the date he/she receives written notice that his/her
     employment is or will be terminated.  If the Employee dies after his
     employment has terminated but before the expiration of such 90-day period,
     he/she shall be deemed to have died on the date his/her employment
     terminated.  As used in this paragraph, the term "Employee", if not
     otherwise defined herein as the holder of the Option, shall mean the
     employee holding the Option.

     2.  This Amendment shall not be effective with respect to an Outstanding
Option unless executed by both Varco and the Employee prior to the termination
of such Outstanding Option in accordance with its terms, without giving effect
to the foregoing amendment.

     3.  The Company and the Employee confirm that, as amended by this
Amendment, each Outstanding Options shall terminate on the 90th day following
the date hereof, or such earlier date as such Outstanding Option shall terminate
in accordance with its terms.

     3.  This Amendment shall be governed by and interpreted in accordance with
the laws of the State of California.

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

                                             "Varco"

                                             VARCO INTERNATIONAL, INC.

                                             By_______________________________
                                                  Richard A. Kertson
                                                  Vice President-Finance

                                             "Employee"

                                             __________________________________
                                                  Signature

                                             __________________________________
                                                  Printed Name

                                       2To:    Compensation Committee                               Exhibit 10.24
From:  Dick Kertson
Date:  February 7, 2000
Re:    Proposed Financial Criteria and Structure--2000 Management Incentive
       Bonus Plan

The general structure of the Plan and the financial performance criteria
employed remain generally unchanged from recent years; however, two additional
financial performance criteria have been included to provide heightened emphasis
on inventory management and new product development.

As in past years, the cash bonus payout is expressed as a percentage of annual
salary and is a function of Salary Grade and the overall financial performance
level achieved.  Overall financial performance is measured by profitability (Net
Income at the total Company level and Operating Income at the Division level)
and return on investment (Economic Value Added or "EVA" at both the total
Company and Division level).  To earn the bonus points associated with a given
level of overall financial performance, both the minimum profit and return on
                                        ----
investment associated with that level must be achieved. In 2000, additional
bonus points may be earned by reaching above-plan inventory turnover and new
product revenue.

In 1999, achieving the "Financial Plan" (the original Annual Financial Plan as
revised in the January quarterly update) equated to 7 Bonus Points for the total
Company (on a scale of 2-15). For the Drilling Systems and Oil Tools Divisions
reaching the Financial Plan generated 10 points, and for M/D Totco, Shaffer and
Rigtech, 6 points. This disparity between target points reflected the fact that
the 1999 Financial Plan for Drilling Systems and Oil Tools was at or above 1997
performance, and for the other three Divisions and the total Company it was
below that of 1997, on approximately the same revenue. The ratio of bonus to
salary which represented the average target percentage in the salary survey data
was set at 7 points, and the 75/th/ percentile ratio was set at 11 points.

1999 financial performance resulted in 13 points for Drilling systems, 7 points
for Oil Tools, 5 points for Shaffer, and 7 points for the total Corporation.
M/D Totco
<PAGE>

and Rigtech did not reach the minimum financial performance necessary to qualify
for a bonus.

Our experience over several years demonstrates that this methodology creates a
very strong relationship between actual financial performance and incentive pay.

A summary of the key elements of the proposed 2000 Management Incentive Bonus
Plan follows:

 .    Achieving the Annual Financial Plan ("AFP") would result in 7 Bonus Points
     for the total Company, as well as each Division (on a scale of 2-15). Each
     of the Division Plans is judged to have approximately the same degree of
     challenge.

 .    In addition, achieving specific inventory turnover and new product revenue
     levels above the AFP enable each Division to earn incremental bonus points
     (or partial points), the sum of which could result in up to 2 additional
     Bonus Points.

 .    Reflecting a significantly lower level of financial performance for the
     Varco International as compared to the 1997-1999 period, the bonus
     percentages (bonus/salary ratio) associated with each Bonus Point level
     have been revised downward for all Salary Grades. The 7 Bonus Point level
     generally yields payout ratios below the 25/th/ percentile when compared to
     the salary survey data. The median ratio would generally equate to the 11-
     12 point level and the 75\th\ percentile ratio to the 13-14 point
     performance level.

In addition to the cash bonus, it is proposed that each participant in the Plan
be once again eligible for a Stock Bonus, based on total Company performance.
As has been the case for several years, the Stock Bonus would be paid in Varco
stock having a value equal to 1/3 of the bonus amount due a participant based on
his/her Salary Grade and the total Company financial performance level achieved.
<PAGE>

For Division Presidents, 30% of the cash bonus amount is based upon the points
attributable to total Company performance.

For 2000 achieving the AFP financial performance would result in Management
Incentive Bonuses totaling approximately $2,265,0000, 6.9% of Pre-Tax Income.
For 1999 the comparable figures were $3,273,000 and 5.5%.

Again in 1998 we propose that Corporate Officers have the opportunity to
increase their cash bonus by 50%, or decrease it by 33%, depending on the
performance of Varco Stock relative to a group of 9 peer companies.
Specifically, if the year-to-year increase in the price of Varco Stock (as
measured by the average of the last 5 trading days of 2000 divided by the
average for the last 5 trading days of 1999) is among the top 3 of 10 companies,
Corporate Officers' cash bonuses would be increased by 50%; if Varco's Stock
price increase is among the bottom 3 of the group such bonuses would be reduced
by 33%. (Note that this element of the Plan comes into play only during stock
price appreciation). We believe that this aspect of the bonus program achieved
its objective of focusing increased attention on stock price performance.

The peer group would again include: Baker Hughes, Halliburton, Schlumberger,
Smith International, Cooper Cameron, Tuboscope International, National Oilwell,
Weatherford International, and IRI.

<PAGE>

                               2000 BONUS POINTS

<TABLE>
<CAPTION>
BONUS POINTS =                       2          3          4          5          6          7          8
                                 --------------------------------------------------------------------------
<S>                                <C>        <C>        <C>        <C>        <C>        <C>        <C>
E.P.S.                             $ 0.05     $ 0.10     $ 0.15     $ 0.20     $ 0.25     $ 0.30     $ 0.35
 NET INCOME                           3.4        6.7       10.1       13.4       16.8       20.1       23.5
 AVERAGE INVESTMENT                 226.2      229.8      233.4      237.0      240.6      244.2      249.6
 NET INCOME R.O.I.                    1.5%       2.9%       4.3%       5.7%       7.0%       8.2%       9.4%
EVA                                $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0
DRILLING SYSTEMS:
 REVENUE                             84.7       89.7       94.8       99.8      104.8      109.8      115.8
 OPERATING INCOME                     7.4        9.2       10.9       12.7       14.4       16.2       18.3
 AVERAGE NET ASSETS                  55.5       56.7       57.9       59.1       60.3       61.5       63.3
EVA                                $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0
OIL TOOLS:
 REVENUE                             36.4       38.6       40.7       42.9       45.0       47.2       49.8
 OPERATING INCOME                     3.5        4.3        5.0        5.8        6.5        7.3        8.1
 AVERAGE NET ASSETS                  16.3       16.8       17.3       17.9       18.4       18.9       19.7
EVA                                $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0
M/D TOTCO:
 REVENUE                             41.7       44.2       46.7       49.2       51.6       54.1       57.1
 OPERATING INCOME                     2.6        3.4        4.3        5.2        6.0        6.9        8.0
 AVERAGE NET ASSETS                  28.7       29.3       29.9       30.5       31.1       31.7       32.6
EVA                                $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0

<CAPTION>
                                     9          10         11         12         13         14         15
                                 --------------------------------------------------------------------------
<S>                              <C>          <C>        <C>        <C>        <C>        <C>        <C>
E.P.S.                             $ 0.40     $ 0.45     $ 0.50     $ 0.55     $ 0.60     $ 0.65     $ 0.70
 NET INCOME                          26.8       30.2       33.5       36.9       40.2       43.6       46.9
 AVERAGE INVESTMENT                 255.0      260.4      265.8      271.2      277.2      283.2      289.2
 NET INCOME R.O.I.                   10.5%      11.6%      12.6%      13.6%      14.5%      15.4%      16.2%
EVA                                $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0
DRILLING SYSTEMS:
 REVENUE                            121.8      127.9      133.9      139.9      146.6      153.3      160.0
 OPERATING INCOME                    20.4       22.5       24.6       26.7       29.1       31.4       33.8
 AVERAGE NET ASSETS                  65.1       66.9       68.7       70.5       72.5       74.5       76.5
EVA                                $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0
OIL TOOLS:
 REVENUE                             52.4       55.0       57.5       60.1       63.0       65.9       68.8
 OPERATING INCOME                     8.9        9.6       10.4       11.2       12.0       12.9       13.8
 AVERAGE NET ASSETS                  20.5       21.2       22.0       22.8       23.6       24.5       25.4
EVA                                $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0
M/D TOTCO:
 REVENUE                             60.0       63.0       66.0       68.9       72.2       75.5       78.8
 OPERATING INCOME                     9.1       10.2       11.2       12.3       13.4       14.6       15.7
 AVERAGE NET ASSETS                  33.5       34.4       35.3       36.1       37.1       38.1       39.1
EVA                                $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0
</TABLE>
<PAGE>

                               2000 BONUS POINTS

<TABLE>
<CAPTION>
                                     2          3          4          5          6          7          8
                                 --------------------------------------------------------------------------
<S>                              <C>          <C>        <C>        <C>        <C>        <C>        <C>
SCHAFFER:
 REVENUE                             77.5       82.1       86.7       91.3       95.9      100.5      106.0
 OPERATING INCOME                     3.0        4.6        6.2        7.8        9.4       11.0       12.4
 AVERAGE NET ASSETS                  72.1       73.2       74.3       75.4       76.5       77.6       79.3
EVA                                $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0
RIGTECH
   REVENUE                           13.0       13.7       14.5       15.3       16.0       16.8       17.7
                                     -1.2       -1.0       -0.7       -0.4       -0.2        0.1        0.5
   AVERAGE NET ASSETS                14.1       14.3       14.4       14.6       14.8       15.0       15.3
EVA                                $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0

<CAPTION>
                                     9         10         11         12         13         14         15
                                 --------------------------------------------------------------------------
<S>                              <C>          <C>        <C>        <C>        <C>        <C>        <C>
SCHAFFER:
 REVENUE                            115.5      117.0      122.5      128.0      134.2      140.3      146.4
 OPERATING INCOME                    13.8       15.1       16.5       17.9       19.3       20.6       22.0
 AVERAGE NET ASSETS                  80.9       82.6       84.2       85.9       87.7       89.5       91.4
EVA                                $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0
RIGTECH
 REVENUE                             18.6       19.6       20.5       21.4       22.4       23.5       24.5
 OPERATING INCOME                     0.9        1.4        1.8        2.4        2.9        3.5        4.1
 AVERAGE NET ASSETS                  15.6       15.8       16.1       16.4       16.7       17.0       17.3
EVA                                $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0     $  0.0
</TABLE>
<PAGE>

                                2000 BONUS PLAN

<TABLE>
<CAPTION>
TOTAL DIVISIONS
<S>                           <C>       <C>      <C>      <C>      <C>      <C>      <C>
   INCREMENTAL REVENUE          15.0     15.0     15.0     15.0     15.0      0.0     18.0
   REVENUE                     253.4    268.4    283.4    298.4    313.4    328.4    346.4
   OPERATING INCOME             15.3     20.5     25.8     31.0     36.3     41.5     47.3
   AVERAGE NET ASSETS          186.7    190.3    193.9    197.5    201.1    204.7    210.1
   OPRA                          8.2%    10.8%    13.3%    15.7%    18.0%    20.3%    22.5%
                                                                   -----

<CAPTION>
TOTAL DIVISIONS
<S>                           <C>        <C>      <C>      <C>      <C>      <C>      <C>
   INCREMENTAL REVENUE           18.0     18.0     18.0     18.0     20.0     20.0     20.0
   REVENUE                      364.4    382.4    400.4    418.4    438.4    458.4    478.4
   OPERATING INCOME              53.0     58.9     64.6     70.4     76.7     83.1     89.4
   AVERAGE NET ASSETS           215.5    220.9    226.3    231.7    237.7    243.7    249.7
   OPRA                          24.6%    26.6%    28.6%    30.4%    32.3%    34.1%    35.8%
</TABLE>
<PAGE>

                                2000 BONUS PLAN

<TABLE>
<CAPTION>
GRADE LEVEL  2        3        4        5        6        7        8        9       10       11       12       13       14      15
-----------------------------------------------------------------------------------------------------------------------------------
<S>          <C>     <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>     <C>
EXEC         0%       0%      30%      35%      40%      45%      50%      55%      60%      65%      70%      80%      85%     95%
16           0%       0%      21%      24%      27%      30%      33%      36%      40%      44%      48%      53%      58%     64%
15           0%       0%      18%      21%      24%      27%      30%      33%      37%      41%      44%      49%      54%     59%
14           0%       0%      16%      18%      20%      22%      25%      28%      31%      34%      37%      40%      44%     49%
13           8%      10%      12%      14%      16%      18%      20%      22%      25%      28%      31%      34%      37%     41%
12           6%       7%       9%      10%      11%      13%      15%      17%      19%      21%      23%      25%      27%     30%
10/11        5%       6%       7%       8%       9%      10%      11%      12%      13%      15%      17%      19%      21%     23%
</TABLE>

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00004-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00004-of-00352.parquet"}], [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00004-of-00352.parquet"}]]