-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0001140361-07-010269.txt : 20070517
<SEC-HEADER>0001140361-07-010269.hdr.sgml : 20070517
<ACCEPTANCE-DATETIME>20070517160549
ACCESSION NUMBER:		0001140361-07-010269
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070517
FILED AS OF DATE:		20070517
DATE AS OF CHANGE:		20070517

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TRIMAS CORP
		CENTRAL INDEX KEY:			0000842633
		STANDARD INDUSTRIAL CLASSIFICATION:	METAL FORGING & STAMPINGS [3460]
		IRS NUMBER:				382687639
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		39400 WOODWARD AVENUE, SUITE 130
		CITY:			BLOOMFIELD HILLS
		STATE:			MI
		ZIP:			48304
		BUSINESS PHONE:		2486315400

	MAIL ADDRESS:	
		STREET 1:		39400 WOODWARD AVENUE, SUITE 130
		CITY:			BLOOMFIELD HILLS
		STATE:			MI
		ZIP:			48304

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			HIP Side-by-Side Partners, LP
		CENTRAL INDEX KEY:			0001399755
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10716
		FILM NUMBER:		07861430

	BUSINESS ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		STREET 2:		3RD FLOOR
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
		BUSINESS PHONE:		203-861-2622

	MAIL ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		STREET 2:		3RD FLOOR
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Metaldyne Investment Fund I, LLC
		CENTRAL INDEX KEY:			0001399760
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10716
		FILM NUMBER:		07861432

	BUSINESS ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		STREET 2:		3RD FLOOR
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
		BUSINESS PHONE:		203-861-2622

	MAIL ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		STREET 2:		3RD FLOOR
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TriMas Investment Fund I, LLC
		CENTRAL INDEX KEY:			0001399756
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10716
		FILM NUMBER:		07861433

	BUSINESS ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		STREET 2:		3RD FLOOR
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
		BUSINESS PHONE:		203-861-2622

	MAIL ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		STREET 2:		3RD FLOOR
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			HEARTLAND INDUSTRIAL ASSOCIATES LLC
		CENTRAL INDEX KEY:			0001179822
		STATE OF INCORPORATION:			DE

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10716
		FILM NUMBER:		07861434

	BUSINESS ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
		BUSINESS PHONE:		2038612622

	MAIL ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TriMas Investment Fund II, LLC
		CENTRAL INDEX KEY:			0001399757
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10716
		FILM NUMBER:		07861435

	BUSINESS ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		STREET 2:		3RD FLOOR
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
		BUSINESS PHONE:		203-861-2622

	MAIL ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		STREET 2:		3RD FLOOR
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Metaldyne Investment Fund II, LLC
		CENTRAL INDEX KEY:			0001399759
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10716
		FILM NUMBER:		07861431

	BUSINESS ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		STREET 2:		3RD FLOOR
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
		BUSINESS PHONE:		203-861-2622

	MAIL ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		STREET 2:		3RD FLOOR
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 3
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2007-05-17</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000842633</issuerCik>
        <issuerName>TRIMAS CORP</issuerName>
        <issuerTradingSymbol>TRS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001179822</rptOwnerCik>
            <rptOwnerName>HEARTLAND INDUSTRIAL ASSOCIATES LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>3RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001399756</rptOwnerCik>
            <rptOwnerName>TriMas Investment Fund I, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>3RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001399760</rptOwnerCik>
            <rptOwnerName>Metaldyne Investment Fund I, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>3RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001399759</rptOwnerCik>
            <rptOwnerName>Metaldyne Investment Fund II, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>3RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001399755</rptOwnerCik>
            <rptOwnerName>HIP Side-by-Side Partners, LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>3RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001399757</rptOwnerCik>
            <rptOwnerName>TriMas Investment Fund II, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>3RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11805779</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F6"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2243827</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F6"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>835339</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F6"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>173378</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F6"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>32952</value>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These securities are owned directly by TriMas Investment Fund I, L.L.C. (?TriMas I?).  Heartland Industrial Associates, L.L.C. (?Heartland?), the Managing Member of TriMas I, is an indirect beneficial owner of these securities.</footnote>
        <footnote id="F2">These securities are owned directly by Metaldyne Investment Fund I, L.L.C. (?Metaldyne I?).  Heartland, the Managing Member of Metaldyne I, is an indirect beneficial owner of these securities.</footnote>
        <footnote id="F3">These securities are owned directly by HIP Side-by-Side Partners, L.P. (?HIP?).  Heartland, the General Partner of HIP, is an indirect beneficial owner of these securities.</footnote>
        <footnote id="F4">These securities are owned directly by TriMas Investment Fund II, L.L.C. (?TriMas II?).  Heartland, the Managing Member of TriMas II, is an indirect beneficial owner of these securities.</footnote>
        <footnote id="F5">These securities are owned directly by Metaldyne Investment Fund II, L.L.C. (?Metaldyne II?).  Heartland, the Managing Member of Metaldyne II, is an indirect beneficial owner of these securities.</footnote>
        <footnote id="F6">Heartland, TriMas I, Metaldyne I,  HIP, TriMas II and Metaldyne II may be deemed to be members of a ?group? for purposes of Section 13(d) of the Securities Exchange Act of 1934 (the ?Exchange Act?).  By reason of TriMas Corporation?s  (the ?Company?) shareholders agreement (the ?Shareholders Agreement?), dated as of June 6, 2002, as amended, holders of an additional 5,534,756 shares of the Company?s common stock have entered into certain voting agreements with affiliates of Heartland.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Heartland Industrial Associates, L.L.C. /s/ Daniel P. Tredwell, Managing Member</signatureName>
        <signatureDate>2007-05-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>TriMas Investment Fund I, L.L.C., By: Heartland Industrial Associates, L.L.C., its Managing Member, /s/ Daniel P. Tredwell, Managing Member</signatureName>
        <signatureDate>2007-05-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>TriMas Investment Fund II, L.L.C., By: Heartland Industrial Associates, L.L.C., its Managing Member, /s/ Daniel P. Tredwell, Managing Member</signatureName>
        <signatureDate>2007-05-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Metaldyne Investment Fund I, L.L.C., By: Heartland Industrial Associates, L.L.C., its Managing Member, /s/ Daniel P. Tredwell, Managing Member</signatureName>
        <signatureDate>2007-05-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Metaldyne Investment Fund II, L.L.C., By: Heartland Industrial Associates, L.L.C., its Managing Member, /s/ Daniel P. Tredwell, Managing Member</signatureName>
        <signatureDate>2007-05-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>HIP Side-by-Side Partners, L.P., By: Heartland Industrial Associates, L.L.C., its Managing Member, /s/ Daniel P. Tredwell, Managing Member</signatureName>
        <signatureDate>2007-05-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----