	UNITED STATES	OMB APPROVAL
	SECURITIES AND EXCHANGE COMMISSION	OMB Number: 3235-0145
	Washington, D.C. 20549	Expires: February 28, 2009
	SCHEDULE 13G	Estimated average burden hours per response...11

Under the Securities Exchange Act of 1934

(Amendment No. 3 )*

Nanometrics Incorporated

(Name of Issuer)

Common Stock

(Title of Class of Securities)

630077105

(CUSIP Number)

01/31/2007

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

x	Rule 13d-1(b)
o	Rule 13d-1(c)
o	Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 630077105

	1.	Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only) The TCW Group, Inc., on behalf of the TCW Business Unit

	2.	Check the Appropriate Box if a Member of a Group (See Instructions)
		(a)		o
		(b)		x

	3.	SEC Use Only

	4.	Citizenship or Place of Organization Nevada corporation

Number of Shares Beneficially Owned by Each Reporting Person With			5.		Sole Voting Power -0-

			6.		Shared Voting Power 846,539

			7.		Sole Dispositive Power -0-

			8.		Shared Dispositive Power 1,848,639

	9.	Aggregate Amount Beneficially Owned by Each Reporting Person 1,848,639

	10.	Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) o

	11.	Percent of Class Represented by Amount in Row (9)

	12.	Type of Reporting Person (See Instructions) HC/CO

Item 1.
	(a)	Name of Issuer Nanometrics Incorporated
	(b)	Address of Issuer’s Principal Executive Offices 1550 Buckeye Drive Milpitas, CA 95035

Item 2.
	(a)	Name of Person Filing
	(b)	Address of Principal Business Office or, if none, Residence
	(c)	Citizenship The TCW Group, Inc., on behalf of the TCW Business Unit 865 South Figueroa Street Los Angeles, CA 90017
	(d)	Title of Class of Securities
	(e)	CUSIP Number 630077105

Item 3.	If this statement is filed pursuant to §§240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
	(a)	o	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).
	(b)	o	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).
	(c)	o	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).
	(d)	o	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C 80a-8).
	(e)	o	An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);
	(f)	o	An employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F);
	(g)	x	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
	(h)	o	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
	(i)	o	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
	(j)	o	Group, in accordance with §240.13d-1(b)(1)(ii)(J).

Item 4.	Ownership
Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.
	(a)	Amount beneficially owned: 1,848,639
	(b)	Percent of class: 10.2%
	(c)	Number of shares as to which the person has:
		(i)	Sole power to vote or to direct the vote none
		(ii)	Shared power to vote or to direct the vote 846,539
		(iii)	Sole power to dispose or to direct the disposition of none
		(iv)	Shared power to dispose or to direct the disposition of 1,848,639

Item 5.	Ownership of Five Percent or Less of a Class
If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following o.

Item 6.	Ownership of More than Five Percent on Behalf of Another Person
Ownership of More than Five Percent on Behalf of Another Person. Various persons other than as described in Item 4 have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Common Stock of Nanometrics Incorporated.

Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company.
See Exhibit A.

Item 8.	Identification and Classification of Members of the Group
Not applicable. See Exhibit A.

Item 9.	Notice of Dissolution of Group
Not applicable.

Item 10.	Certification
Because this statement is filed pursuant to Rule 13d-1(b), the following certification is included: By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

Signature

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

	February 14, 2007
	Date
	The TCW Group, Inc., on behalf of the TCW Business Unit By: /s/ Linda D. Barker
	Signature
	Linda D. Barker Authorized Signatory
	Name/Title