<TABLE> <S> <C>

<ARTICLE> 5
<MULTIPLIER> 1,000

<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   6-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1997             DEC-31-1997
<PERIOD-END>                               MAR-31-1997             JUN-30-1997             SEP-30-1997
<CASH>                                           8,888                  13,761                   8,063
<SECURITIES>                                         0                       0                       0
<RECEIVABLES>                                   29,743                  29,836                  33,495
<ALLOWANCES>                                     1,071                   1,005                   1,070
<INVENTORY>                                     13,571                  14,345                  14,582
<CURRENT-ASSETS>                                54,838                  60,737                  59,230
<PP&E>                                          83,799                  85,610                  87,618
<DEPRECIATION>                                  44,833                  46,345                  47,626
<TOTAL-ASSETS>                                 120,260                 126,338                 125,231
<CURRENT-LIABILITIES>                           29,743                  32,993                  34,215
<BONDS>                                         15,714                  15,671                  12,518
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                           119                     119                     119
<OTHER-SE>                                      67,927                  70,860                  71,796
<TOTAL-LIABILITY-AND-EQUITY>                   120,260                 126,338                 125,231
<SALES>                                         46,408                  95,015                 151,452
<TOTAL-REVENUES>                                46,408                  95,015                 151,452
<CGS>                                           28,526                  58,379                  92,503
<TOTAL-COSTS>                                   12,338                  24,375                  36,570
<OTHER-EXPENSES>                                   168                     383                     389
<LOSS-PROVISION>                                     0                       0                       0
<INTEREST-EXPENSE>                                 478                     907                   1,335
<INCOME-PRETAX>                                  4,995                  11,164                  20,972
<INCOME-TAX>                                     1,885                   4,136                   7,783
<INCOME-CONTINUING>                              3,110                   7,028                  13,189
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                     3,110                   7,028                  13,189
<EPS-PRIMARY>                                      .27                     .62                    1.16
<EPS-DILUTED>                                      .26                     .60                    1.13


</TABLE>