<PAGE>

                                                                   EXHIBIT 10(F)
                          [Letterhead of AmSouth Bank]

                                  April 1, 2002


Martin Industries, Inc.
Attention: Mr. James W. Truitt
Vice President and Chief Financial Officer
P.O. Box 128
Florence, Alabama 35631

Re:      Line of Credit (Account #120435-524769); Loan Agreement dated January
         7, 1993, as amended April 5, 1994, February 17, 1995, March 15, 1995,
         March 28, 1996, August 28, 1997, January 1, 2000, December 29, 2000,
         January 31, 2001, March 15, 2001, May 15, 2001, June 15, 2001,
         September 1, 2001, October 15, 2001, October 31, 2001, November 9,
         2001, November 19, 2001, November 26, 2001, December 19, 2001 and
         January 11, 2002 (collectively "Loan Agreement") by and among Martin
         Industries, Inc. ("Martin Industries") and AmSouth Bank ("the Bank").
         In this letter capitalized terms shall be given the meanings indicated
         in the Loan Agreement and/or in this letter.

Dear Mr. Truitt:

I am writing this letter to you concerning the indebtedness ("Indebtedness")
referenced above of Martin Industries to the Bank and your recent request that
the Loan Agreement be amended to effect an extension of the Line of Credit
Termination Date. You have also requested a waiver of certain covenants included
in the Loan Agreement.

In response to your requests, the Bank hereby amends the Loan Agreement as
follows:

         A.       The definition of "Line of Credit Termination Date" in Section
1.02 is amended as follows:

                  LINE OF CREDIT TERMINATION DATE shall mean the earlier to
                  occur of (a) the date on which an Event of Default occurs or
                  (b) July 1, 2002 (or such later termination date as the
                  Borrower and the Lender hereafter agree on in a written
                  extension agreement pursuant to Section 3).

Effective as of April 1, 2002, all references in the Loan Documents to the "Loan
Agreement" shall mean the Loan Agreement, as heretofore modified and amended and
as further modified and amended hereby.


                                       1
<PAGE>



In all other respects, the Loan Agreement shall remain in full force and effect
in accordance with its terms.


In addition to the foregoing, the Bank waives any default or Event of Default
arising out of the Borrower's failure to comply with Sections 8.09, 8.11, 8.12,
8.13 and 8.20 of the Loan Agreement with respect to the fiscal periods ended
through March 31, 2002.

We are also aware that Martin Industries is in discussions to obtain financing
in an amount of up to $2.0 million from M-TIN, LLC (the "M-TIN Loan"). We
understand that the indebtedness will be secured by a first mortgage in favor of
M-TIN, LLC on Martin Industries' real property located in the Alabama counties
of Colbert, Limestone and Lauderdale (the "Properties"). We acknowledge and
consent to Martin Industries obtaining the M-TIN Loan and waive the covenants
contained in Sections 8.02 and 8.03 of the Loan Agreement dated January 7, 1993,
as amended, with respect to the proposed transaction with M-TIN, LLC. We also
waive with respect to the M-TIN Loan the agreement contained in our letter to
Martin Industries dated October 22, 2001, which requires that one half of the
proceeds of any loan obtained by Martin Industries which is secured by the
Properties be paid to AmSouth Bank to reduce the Company's line of credit.

In addition, the Bank agrees that the payment of the fee in the amount of One
Hundred Thousand and No/100 Dollars ($100,000) due to be paid to the Bank by
Martin Industries on April 1, 2002 (the "Maturity Fee"), is extended to July 1,
2002; provided, however, that if Martin Industries pays in full all amounts
outstanding under the Line of Credit Note on or before April 30, 2002, Martin
Industries shall not be obligated to pay the Maturity Fee; and, provided
further, that if Martin Industries pays in full all amounts outstanding under
the Line of Credit Note following April 30, 2002, but on or before May 31, 2002,
Martin Industries shall be obligated to pay only one-half of the Maturity Fee
($50,000.00).

To evidence the acceptance of the foregoing amendments and agreements on the
terms and conditions set forth herein, please sign and return to me the enclosed
copy of this letter agreement. By so signing the enclosed copy of this letter
agreement, Martin Industries acknowledges and agrees to the following terms and
conditions of such amendments and agreements:

1.       This letter agreement shall not be deemed to be an accord and
         satisfaction of the Indebtedness or any other obligation owed to the
         Bank.

2.       All collateral that now secures all or any of the Indebtedness shall
         continue to secure same. Nothing in this letter agreement diminishes
         any security interest or lien that the Bank has in any assets securing
         the Indebtedness. All of the collateral, rights, security, and
         guarantees that the Bank now has to secure any of the Indebtedness due
         from Martin Industries shall remain in full force and effect and are
         hereby ratified and confirmed.

3.       The Bank reserves all of its rights and remedies under the Loan
         Agreement, the Security Documents, any other Loan Documents, and/or
         applicable law, in respect of any Event(s) of


                                       2
<PAGE>


         Default. The current non-exercise by the Bank of any rights and
         remedies which it may have shall not constitute a release or waiver of
         any of its rights and/or remedies or a release or waiver of any
         Event(s) of Default under the Loan Agreement, the Security Documents,
         or any other Loan Documents, except for the Waiver provided in this
         letter agreement. The Bank specifically reserves the right to invoke
         any and all rights and remedies at any time in its sole discretion.

4.       Martin Industries hereby releases, satisfies, cancels, waives, acquits,
         and forever discharges the Bank, its directors, officers, employees,
         agents, attorneys, successors and assigns, of and from any and all
         claims, demands, actions, or causes of action of any kind or character,
         arising at any time in the past, up to and including the date of this
         letter agreement, which relate or pertain in any way to the
         Indebtedness and/or collection of them.

5.       The Indebtedness is owed by Martin Industries to the Bank for the
         amount (exclusive of outstanding letters of credit, ACH exposures and
         the Bank's attorneys fees) herein stated and there are no defenses,
         setoffs, or counterclaims with respect thereto:

<TABLE>
<CAPTION>

                                                                                       Payoff as of
         General Description                       Obligation No.                          4/1/02
-------------------------------------       ---------------------------         --------------------------
<S>                                         <C>                                 <C>
         Line of Credit                                #524769                        $5,705,956.37

</TABLE>

6.       Martin Industries agrees to pay the Indebtedness strictly and promptly
         in accordance with the terms of the applicable promissory notes or
         other debt instruments, as specifically modified by the Loan Agreement
         and this letter agreement.

7.       Martin Industries shall pay to the Bank a fee in the total amount of
         Ten Thousand and No/100 Dollars ($10,000.00), $5,000 of which (the
         "Closing Fee") shall be payable upon the execution of this letter
         agreement and $5,000 of which shall be payable on April 30, 2002.
         Subject to the terms and conditions otherwise applicable to the making
         of Advances under the Loan Agreement, Martin Industries may request and
         receive an Advance to pay the Closing Fee.

8.       In the event Martin Industries does not pay in full all amounts
         outstanding under the Line of Credit on or before June 30, 2002, Martin
         Industries will issue to the Bank warrants to purchase common stock in
         Martin Industries equal to ten percent (10%) of the outstanding shares
         of Martin Industries for a per share purchase price to be agreed upon
         by the Bank and Martin Industries. Martin Industries and the Bank agree
         to negotiate in good faith and establish the per share purchase price
         on or before April 5, 2002. The failure by the parties to establish the
         per share purchase price by April 5, 2002, shall constitute an Event of
         Default under the Loan Agreement.

9.       Martin Industries agrees to grant to the Bank a mortgage in the
         Properties (the "Second Mortgage"), subject to the first priority
         mortgage in favor of M-TIN, LLC. The Second


                                       3
<PAGE>

         Mortgage shall be subordinate to the mortgage in favor of M-TIN, LLC
         securing only the M-TIN Loan and shall further provide that it shall
         also be subordinated to any financing obtained by Martin Industries
         which replaces the M-TIN Loan, provided such substitute financing does
         not exceed $2 million. The Bank will be subordinated to the amount of
         any such replacement financing in an amount which is the lesser of (i)
         the amount outstanding on the M-TIN Loan at the time of the replacement
         financing, or (ii) $2 million. Further, in the event Martin Industries
         obtains replacement financing which is secured by the Properties and is
         in excess of $2 million, Martin Industries shall pay to the Bank one
         half of the amount received in excess of $2 million to reduce the
         Indebtedness. Martin Industries and the Bank will enter into
         documentation deemed necessary by the parties to effect the Second
         Mortgage on or before April 5, 2002.

10.      Martin Industries agrees to pay to the Bank's counsel, Wilmer, Lee &
         Rowe, P.A., on or before April 30, 2002, all of its attorney's fees
         incurred in connection with this amendment, the Second Mortgage and/or
         the collection of the Indebtedness.


                                             Very truly yours,

                                             /s/ DARLENE CHANDLER

                                             Darlene Chandler
                                             Vice President

cc:      Denson N. Franklin III, Esq.
         S. Dagnal Rowe, Esq.


ACCEPTED AND AGREED TO BY:

                MARTIN INDUSTRIES, INC.

By:               /s/ JAMES W. TRUITT
    -------------------------------------------------
                    James W. Truitt
    Its Vice President and Chief Financial Officer


                                       4