This Amendment No. 1 (“Amendment No. 1”) amends and supplements the Tender Offer Statement on Schedule TO (the “Schedule TO”) originally filed on October 15, 2012 by Cyborg Acquisition Corporation, a Delaware corporation (“Purchaser”) and a direct wholly owned subsidiary of 3M Company, a Delaware corporation (“3M”), to purchase all issued and outstanding shares of common stock, par value $0.01 per share (the “Shares”), of Ceradyne, Inc., a Delaware corporation (“Ceradyne”), at a price of $35.00 per Share, net to the seller in cash, without interest thereon and less any required withholding taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase dated October 15, 2012 (the “Offer to Purchase”), which is annexed to and filed with the Schedule TO as Exhibit (a)(1)(A), and in the related Letter of Transmittal, which is annexed to and filed with the Schedule TO as Exhibit (a)(1)(B), which, together with any amendments or supplements thereto, collectively constitute the “Offer.”

All capitalized terms used in this Amendment No. 1 without definition have the meanings ascribed to them in the Schedule TO.

The items of the Schedule TO set forth below are hereby amended and supplemented as follows:

Item 2.    Subject Company Information

Section 8—“Certain Information Concerning Ceradyne—Prospective Financial Information” of the Offer to Purchase is hereby amended by:

On page 18, replacing the lead-in sentence of each table and the tables and footnotes in their entirety with the following lead-in sentences, tables and footnotes:

The following is a summary of the prospective financial information Ceradyne provided to 3M on June 28, 2012:

The following is a summary of the updated prospective financial information Ceradyne provided to 3M on July 27, 2012:

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The following is a summary of the updated prospective financial information Ceradyne provided to 3M on September 5, 2012:

(1)                                 Net cash provided by operating activities consists of (i) net income plus (ii) depreciation and amortization, increases or decreases in net working capital and certain other adjustments, and it excludes (i) purchases of property, plant and equipment, (ii) purchases or sales of marketable securities, (iii) dividends paid, (iv) payments made on long-term debt and (v) certain other adjustments.

(2)                                 The reconciliation of non-GAAP measures to GAAP net income data was not provided by Ceradyne to 3M.  The reconciliation information included herein is based solely on the reconciliation of such non-GAAP measures that was included in the Schedule 14D-9.

(3)                                 Net income data may include incidences of immaterial rounding to arrive at net income.

Item 11.    Additional Information.

Section 15—“Certain Legal Matters—Antitrust Compliance” of the Offer to Purchase is hereby amended and supplemented by adding the following paragraphs:

On October 15, 2012, the FTC granted Purchaser’s request for early termination of the waiting period required under the HSR Act, thus ending the required waiting period with respect to the Offer and the Merger.

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3M filed the required notice forms with the FCO on October 16, 2012 and received clearance from the FCO on October 30, 2012.

On October 18, 2012, 3M filed the required notice forms with the FCA.

Section 15—“Certain Legal Matters—Litigation” of the Offer to Purchase is hereby amended and restated in its entirety as follows:

Litigation.            Between October 9 and October 19, 2012, four plaintiffs filed putative class actions against Ceradyne, its directors, 3M and Purchaser in connection with the Offer and the proposed Merger.  Two suits were filed in California Superior Court for the County of Orange and two suits were filed in the Delaware Court of Chancery.  The suits seek principally to enjoin the Offer and the proposed Merger, and allege that the defendants breached and/or aided and abetted the breach of their fiduciary duties to Ceradyne by seeking to sell Ceradyne through an allegedly unfair process and for an unfair price and on unfair terms, and/or by allegedly failing to make adequate disclosures to Ceradyne stockholders regarding the Offer and the proposed Merger.  The California Superior Court, upon the parties’ stipulation, consolidated those two actions, set an expedited briefing schedule, and set a preliminary injunction hearing for November 26, 2012.  The Delaware Chancery Court similarly consolidated the two Delaware actions, and on November 2, 2012 denied the plaintiffs’ motion for expedited proceedings, ruling that the plaintiffs had presented no colorable claims.  3M believes the allegations in all of these cases are without merit, and is defending the actions vigorously.

Additional details regarding the four actions are as follows:

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SIGNATURE

After due 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.

Dated: November 2, 2012

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