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                                                                   Exhibit 4.2.1

                               FIRST AMENDMENT TO
                              THE CREDIT AGREEMENT


        This FIRST AMENDMENT, dated as of October 23, 1997 (this "AMENDATORY
AGREEMENT"), to the Existing Credit Agreement (as defined below), is made among
DAYTON SUPERIOR CORPORATION, an Ohio corporation (the "BORROWER"), the various
financial institutions signatories hereto (the "LENDERS"), DLJ CAPITAL FUNDING,
INC., as syndication agent (the "SYNDICATION AGENT") for the Lenders, BANK OF
AMERICA NATIONAL TRUST AND SAVINGS ASSOCIATION, as documentation agent (the
"DOCUMENTATION AGENT") for the Lenders, BANKERS TRUST COMPANY, as administrative
agent (the "ADMINISTRATIVE AGENT") for the Lenders and BANK ONE, N.A., as
facility agent (the "FACILITY AGENT") for the Lenders.


                                  WITNESSETH:
                                  ----------- 

        WHEREAS, the Borrower, the Lenders, and the Agents are parties to a
Credit Agreement, dated as of September 29, 1997 (the "EXISTING CREDIT
AGREEMENT")

        WHEREAS, the Borrower has requested that the Lenders amend the Existing
Credit Agreement in certain respects; and

        WHEREAS, the Lenders have agreed, subject to the terms and conditions
hereinafter set forth, to amend the Existing Credit Agreement in certain
respects as provided below (the Existing Credit Agreement, as so amended by this
Amendatory Agreement, being referred to as the "CREDIT AGREEMENT")

        NOW, THEREFORE, in consideration of the agreements herein contained, the
parties hereto agree as follows:


                                     PART I
                                  DEFINITIONS

        SUBPART 1.1. CERTAIN DEFINITIONS. The following terms (whether or not
underscored) when used in this Amendatory Agreement shall have the following
meanings (such meanings to be equally applicable to the singular and plural form
thereof):

        "ADMINISTRATIVE AGENT" is defined in the PREAMBLE.

        "AMENDATORY AGREEMENT" is defined in the PREAMBLE.
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        AMENDMENT NO. 1 " is defined in SUBPART 3.1.

        "BORROWER" is defined in the PREAMBLE.

        "CREDIT AGREEMENT" is defined in the THIRD RECITAL.

        "DOCUMENTATION AGENT" is defined in the PREAMBLE.

        "EXISTING CREDIT AGREEMENT" is defined in the FIRST RECITAL.

        "FACILITY AGENT" is defined in the PREAMBLE.

        "FIRST AMENDMENT EFFECTIVE DATE" is defined in SUBPART 3.1.

        "LENDERS" is defined in the PREAMBLE.

        "SYNDICATION AGENT" is defined in the PREAMBLE.

        SUBPART 1.2. OTHER DEFINITIONS. Terms for which meanings are provided in
the Existing Credit Agreement are, unless otherwise defined herein or the
context otherwise requires, used in this Amendatory Agreement with such
meanings.


                                    PART II
                               AMENDMENTS TO THE
                           EXISTING CREDIT AGREEMENT

        Effective on (and subject to the occurrence of) the First Amendment
Effective Date, the Existing Credit Agreement is hereby amended in accordance
with this Part II. Except as so amended, the Existing Credit Agreement shall
continue in full force and effect in accordance with its terms.

        SUBPART 2.1. AMENDMENTS TO SECTION 1.1. Section 1.1 of the Existing
Credit Agreement is hereby amended by inserting the following definitions in
such Section in the appropriate alphabetical sequence:

                "AMENDMENT NO. 1" means the First Amendment to the Credit
        Agreement, dated as of October 23, 1997, among the Borrower, the Lenders
        signatory thereto, and the Agents.

                "APPROVED FUND" means, with respect to any Lender that is a fund
        that invests in commercial loans, any other fund that invests in
        commercial loans and is managed or advised by the same investment
        advisor as such Lender or by an Affiliate of such investment advisor. 

                                      -2-
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                "FIRST AMENDMENT EFFECTIVE DATE" is defined in Subpart 3.1 of
        Amendment No. 1.


        "NON-U.S. LENDER" means any Lender (including each Assignee Lender) that
is not (i) a citizen or resident of the United States, (ii) a corporation,
partnership or other entity created or organized in or under the laws of the
United States or any state thereof, or (iii) an estate or trust that is subject
to U.S. Federal income taxation regardless of the source of its income.

        "REGISTER" is defined in CLAUSE (b) of SECTION 2.8.

        "REGISTERED NOTE" means a promissory note of the Borrower payable to any
Registered Noteholder, in the form of EXHIBIT B-1 hereto (as such promissory
note may be amended, endorsed or otherwise modified from time to time),
evidencing the aggregate Indebtedness of the Borrower to such Lender resulting
from outstanding Revolving Loans or Term Loans, and also means all other
promissory notes accepted from time to time in substitution therefor or renewal
thereof.

        "REGISTERED NOTEHOLDER" means any Lender that has been issued a
Registered Note.

        SUBPART 2.2. The Existing Credit Agreement is hereby amended by adding a
new Section 2.8 thereof to read as follows:

                SECTION 2.8 REGISTERED NOTES. (a) Any Lender may request the
        Borrower (through the Facility Agent), and the Borrower agrees (i) to
        exchange for any Notes held by such Lender, or (ii) to issue to such
        Lender on the date it becomes a Lender, promissory notes(s) registered
        as provided in CLAUSE (b) of this SECTION 2.8 (each, a "REGISTERED
        NOTE", to be in substantially the form of EXHIBIT B-1 hereto).
        Registered Notes may not be exchanged for Notes that are not Registered
        Notes.

                (b) The Borrower shall maintain, or cause to be maintained, a
        register (the "REGISTER") (which, at the request of the Borrower, shall
        be kept by the Facility Agent on behalf of the Borrower at no extra
        charge to the Borrower at the address to which notices to the Facility
        Agent are to be sent under this Agreement) on which it enters the name
        of the registered owner of the Lender's Obligation(s) evidenced by a
        Registered Note and the amount of such Obligations(s).

                (c) The Register shall be available for inspection by the
        Borrower and any Lender at any reasonable time upon reasonable prior
        notice.

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        SUBPART 2.3. Section 4.6 of the Existing Credit Agreement is hereby
amended by adding a new clause (c) thereof to read as follows:

        (c) Each Non-U.S. Lender shall, (i) on or prior to the date it becomes a
Lender, execute and deliver to the Borrower and the Facility Agent, two or more
(as the Borrower or the Agents may reasonably request) United States Internal
Revenue Service Forms 4224 or Forms 1001 or, solely if such Lender is claiming
exemption from United States withholding tax under Section 871(h) or 881(c) of
the Code with respect to payments of "portfolio interest", United States
Internal Revenue Service Forms W-8 and a certificate signed by a duly authorized
officer of such Lender representing that such Lender is not a "bank" within the
meaning of Section 881 (c)(3)(A) of the Code, or such other forms or documents
(or successor forms or documents), appropriately completed, establishing that
payments to such Lender are exempt from withholding or deduction of Taxes; and
(ii) deliver to the Borrower and the Facility Agent two further copies of any
such form or documents on or before the date that any such form or document
expires or becomes obsolete and after the occurrence of any event requiring a
change in the most recent such form or document previously delivered by it to
the Borrower.

        SUBPART 2.4. Clause (b) of Section 10.11.1 of the Existing Credit
Agreement is hereby amended to read as follows:

                (b) with notice to the Borrower, the Facility Agent and (in the
        case of any assignment of participations in Letters of Credit or
        Revolving Loan Commitments) the Issuer, but without the consent of the
        Borrower, the Facility Agent or the Issuer, may assign and delegate to
        any of its Affiliates, to any other Lender or to an Approved Fund of any
        Lender

        SUBPART 2.5. The Existing Credit Agreement is hereby amended by adding a
new Section 10.11.3 thereof to read as follows:

        SECTION 10.11.3. ASSIGNMENT OF REGISTERED NOTES. A Registered Note and
the Obligations evidenced thereby may be assigned or otherwise transferred in
whole or in part pursuant to the terms of SECTION 10.11.1 and only by
registration of such assignment or transfer of such Registered Note and the
Obligations evidenced thereby on the Register (and each Registered Note shall
expressly so provide). Any assignment or transfer of all or part of such
Obligations and the Registered Note(s) evidencing the same shall be registered
on the Register only upon surrender for registration of assignment or transfer
of the Registered Note(s) evidencing such Obligations, duly endorsed by (or
accompanied by a written instrument of assignment or transfer duly executed by)
the Registered Noteholder thereof, and thereupon one or more new Registered
Note(s) in the same aggregate principal amount shall be issued to the designated
Assignee Lender, and the old Registered Note(s) shall be returned by the
Facility Agent to the Borrower marked "canceled." Prior to the due presentment
for registration of assignment or transfer of any Registered Note, the Borrower
and the Agents shall treat the Person in whose name such Obligations and the
Registered Note(s) evidencing the same is 

                                      -4-
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registered as the owner thereof for the purpose of receiving all payments
thereon and for all other purposes, notwithstanding any notice to the contrary.

        SUBPART 2.6. The existing Credit Agreement is hereby amended by adding a
new Exhibit B-1 thereto (Form of Registered Note) as set forth on Annex I
attached hereto.


                                    PART III
                          CONDITIONS TO EFFECTIVENESS

        SUBPART 3.1. FIRST AMENDMENT EFFECTIVE DATE. This Amendatory Agreement
(and the amendments and modifications contained herein) shall become effective,
and shall thereafter be referred to as "Amendment No. 1", on the date (the
"FIRST AMENDMENT EFFECTIVE DATE") when all of the conditions set forth in this
SUBPART 3.1 have been satisfied.

        SUBPART 3.1.1. EXECUTION OF COUNTERPARTS. The Syndication Agent shall
have received counterparts of this Amendatory Agreement, duly executed and
delivered on behalf of the Borrower and each of the Required Lenders.

        SUBPART 3.1.2. LEGAL DETAILS, ETC. All documents executed or submitted
pursuant hereto shall be satisfactory in form and substance to the Agents and
their counsel. The Agents and their counsel shall have received all information
and such counterpart originals or such certified or other copies or such
materials, as the Agents or their counsel may reasonably request, and all legal
matters incident to the transactions contemplated by this Amendatory Agreement
shall be satisfactory to the Agents and their counsel.


                                    PART IV
                                 MISCELLANEOUS

        SUBPART 4.1. CROSS-REFERENCES. References in this Amendatory Agreement
to any Part or Subpart are, unless otherwise specified or otherwise required by
the context, to such Part or Subpart of this Amendatory Agreement.

        SUBPART 4.2. LOAN DOCUMENT PURSUANT TO EXISTING CREDIT AGREEMENT. This
Amendatory Agreement is a Loan Document executed pursuant to the Existing Credit
Agreement and shall be construed, administered and applied in accordance with
all of the terms and provisions of the Existing Credit Agreement.

        SUBPART 4.3. COMPLIANCE WITH WARRANTIES. NO DEFAULT. ETC. The Borrower
represents and warrants on the First Amendment Effective Date for its
Subsidiaries and itself, both before and after giving effect to this Amendatory
Agreement, as follows:

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                (a) the representations and warranties set forth in Article VI
        of the Credit Agreement (excluding those contained in Section 6.7
        thereof) and in each other Loan Document are, in each case, true and
        correct in all material respects (unless stated to relate solely to an
        earlier date, in which case such representations and warranties were
        true and correct in all material respects as of such earlier date);

                (b) no adverse development has occurred in any litigation,
        action, proceeding, labor controversy, arbitration or governmental
        investigation disclosed pursuant to Section 6.7 of the Credit Agreement
        which could reasonably be expected to have a Material Adverse Effect;

                (c) the sum of (A) the aggregate outstanding principal amount of
        all Revolving Loans and (B) the aggregate amount of all Letter of Credit
        Outstandings does not exceed the lesser of(c) the Revolving Loan
        Commitment Amount and (y) the Borrowing Base Amount; and

                (d) no Default has occurred and is continuing, and neither the
        Borrower, any other Obligor, nor any of its Subsidiaries are in material
        violation of any law or governmental regulation or court order or
        decree.

        SUBPART 4.4. SUCCESSORS AND ASSIGNS. This Amendatory Agreement shall be
binding upon and inure to the benefit of the parties hereto and their respective
successors and assigns.

        SUBPART 4.5. COUNTERPARTS. This Amendatory Agreement may be executed by
the parties hereto in several counterparts, each of which when executed and
delivered shall be deemed to be an original and all of which shall constitute
together but one and the same agreement.

        SUBPART 4.6. GOVERNING LAW. THIS AMENDATORY AGREEMENT SHALL BE
GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE INTERNAL
LAWS OF THE STATE OF NEW YORK.

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        IN WITNESS WHEREOF, the parties hereto have caused this Amendatory
Agreement to be executed by their respective officers thereunto duly authorized
as of the day and year first above written.


                                    DAYTON SUPERIOR CORPORATION             
                                                                            
                                                                            
                                                                            
                                                                            
                                    BANK ONE, N.A., as                      
                                    Facility Agent, the Issuer and a Lender 
                                                                            
                                                                            
                                                                            
                                                                            
                                    DUJ CAPITAL FUNDING, INC., as           
                                      Syndication Agent and a Lender        
                                                                            
                                                                            
                                                                            
                                                                            
                                    BANKERS TRUST COMPANY, as               
                                      Administrative Agent and a Lender     
                                                                            
                                                                            
                                                                            
                                                                            
                                    BANK OF AMERICA NATIONAL TRUST AND      
                                    SAVINGS ASSOCIATION, as                 
                                      Documentation Agent and a Lender      
                                                                            
                                    
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                                    NATIONAL CITY BANK OF DAYTON, as
                                      a Lender






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                                                                         ANNEX I
                                                                     EXHIBIT B-1


                                REGISTERED NOTE

        THIS REGISTERED NOTE MAY NOT BE TRANSFERRED EXCEPT IN
        COMPLIANCE WITH THE TERMS AND PROVISIONS OF THE CREDIT
        AGREEMENT REFERRED TO BELOW. TRANSFERS OF THIS
        REGISTERED NOTE MUST BE RECORDED IN THE REGISTER
        MAINTAINED BY THE FACILITY AGENT PURSUANT TO THE TERMS OF
        SUCH CREDIT AGREEMENT.

$___________________                                   ______________ ___, ____



        FOR VALUE RECEIVED, the undersigned, DAYTON SUPERIOR CORPORATION, an
Ohio corporation (the "BORROWER") , promises to pay to the order of
__________________ (the "LENDER") the principal sum of _________________ DOLLARS
($ ________) or, if less, the aggregate unpaid principal amount of all the [Term
and Revolving] Loans shown on the schedule attached hereto (and any continuation
thereof) made by the Lender pursuant to that certain Credit Agreement, dated as
of September 29, 1997 (as amended, supplemented, amended and restated or
otherwise modified from time to time, the "CREDIT AGREEMENT") , among the
Borrower, the various financial institutions as are or may become parties
thereto, DLJ Capital Funding, Inc., as the Syndication Agent, Bankers Trust
Company, as the Administrative Agent, Bank of America National Trust and Savings
Association, as the Documentation Agent and Bank One, N.A., as the Facility
Agent for the Lenders, payable as set forth in the Credit Agreement and on the
Stated Maturity Date for all [Term and Revolving] Loans. Unless otherwise
defined, terms used herein have the meanings provided in the Credit Agreement.

        The Borrower also promises to pay interest on the unpaid principal
amount hereof from time to time outstanding from the date hereof until maturity
(whether by acceleration or otherwise) and, after maturity, until paid, at the
rates per annum and on the dates specified in the Credit Agreement.

        Payments of both principal and interest are to be made in lawful money
of the United States of America in same day or immediately available funds to
the account designated by the Facility Agent pursuant to the Credit Agreement.

        This Registered Note is one of the Notes referred to in, and evidences
Indebtedness incurred under, the Credit Agreement, to which reference is made
for a description of the security for this Registered Note and for a statement
of the terms and 
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conditions on which the Borrower is permitted and required to make prepayments
and repayments of principal of the Indebtedness evidenced by this Registered
Note and on which such Indebtedness may be declared to be immediately due and
payable.

        As provided in Section 10.11.3 of the Credit Agreement, this Registered
Note and the Obligation(s) evidenced hereby may be assigned or otherwise
transferred in whole or in part only by registration of such assignment or
transfer of this Registered Note and the Obligation(s) evidenced hereby on the
Register described in clause (b) of Section 2.8 of the Credit Agreement. Any
assignment or transfer of all or part of such Obligations(s) and this Registered
Note evidencing the same shall be registered on the Register only upon surrender
for registration of assignment or transfer of this Registered Note evidencing
such Obligations(s), duly endorsed by (or accompanied by a written instrument of
assignment or transfer duly executed by) the Registered Noteholder hereof, and
thereupon one or more new Registered Note(s) in the same aggregate principal
amount shall be issued to the designated Assignee Lender, and this Registered
Note shall be returned by the Facility Agent to the Borrower marked "canceled".
Prior to the due presentment for registration of assignment or transfer of this
Registered Note, the Borrower and the Facility Agent shall treat the Person in
whose name such Obligation(s) and this Registered Note(s) evidencing the same is
registered as the owner thereof for the purpose of receiving all payments
thereon and for all other purposes, notwithstanding any notice to the contrary.
This Registered Note may not be exchanged for promissory notes that are not
Registered Notes.

        All parties hereto, whether as makers, endorsers, or otherwise,
severally waive presentment for payment, demand, protest and notice of dishonor.

                                       2
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        THIS NOTE HAS BEEN DELIVERED IN NEW YORK, NEW YORK AND SHALL
BE DEEMED TO BE A CONTRACT MADE UNDER AND GOVERNED BY THE
INTERNAL LAWS OF THE STATE OF NEW YORK.

                                        DAYTON SUPERIOR CORPORATION


                                        By___________________________
                                          Title:




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