<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-07-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001005229</issuerCik>
        <issuerName>COLUMBUS MCKINNON CORP</issuerName>
        <issuerTradingSymbol>CMCO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001509464</rptOwnerCik>
            <rptOwnerName>Korman Alan S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>205 CROSSPOINT PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GETZVILLE</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>14068</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP, Gen'l Counsel &amp; Secretary</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-07-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>638.344</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>44.39</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>33270.9866</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">1,676.3440 restricted stock units became fully vested on 7/20/2021, of which 638 were traded and .3440 were converted to cash to satisfy tax withholding obligations.</footnote>
        <footnote id="F2">Includes 15,222.9866 shares of restricted stock issued to reporting person subject to forfeiture in whole or part; 715.3007 shares become fully vested 5/22/2022; 1,443.8112 shares become fully vested 50% per year for two years beginning 5/20/2022; 447.8349 shares become fully vested 5/20/2022, 2,588.4832 shares become fully vested 1/20/2022, 2,847.8742 shares become fully vested 50% per year for two years beginning 5/18/2022, 3,351.6824 shares become fully vested and non-forfeitable 50% per year for two years beginning 7/20/2022, and 3,828 shares become fully vested 33.33% per year for three years beginning 5/17/2022, if reporting person remains an employee of issuer.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Alan S. Korman</signatureName>
        <signatureDate>2021-07-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
