SC TO-I/A

QuickLinks -- Click here to rapidly navigate through this document

SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

SCHEDULE TO/A
(Rule 14d-100)

TENDER OFFER STATEMENT UNDER SECTION 14(D)(1) OR 13(E)(1)
OF THE SECURITIES EXCHANGE ACT OF 1934
AMENDMENT NO. 1

COLLINS INDUSTRIES, INC.
(Name of Subject Company)

COLLINS INDUSTRIES, INC.
(Name of Filing Persons—Offeror)

COMMON STOCK, PAR VALUE $.10 PER SHARE
(Title of Class of Securities)

194858106
(CUSIP Number of Class of Securities)

Mr. Donald Lynn Collins
President and Chief Executive Officer
15 Compound Drive
Hutchinson, Kansas 67502-4349
(620) 663-5551
(Name, Address and Telephone Number of Person Authorized to
Receive Notices and Communications on Behalf of Bidder)

Copies to:
Gary D. Gilson, Esq.
Blackwell Sanders Peper Martin LLP
Two Pershing Square
2300 Main Street, Suite 1000
Kansas City, Missouri 64108
(816) 983-8000

CALCULATION OF FILING FEE

Transaction Valuation*
$4,950,000 Amount of Filing Fee**
$400.45

*

Estimated for purposes of calculating the filing fee only, in accordance with Rule 0-11 of the Securities Exchange Act of 1934. This calculation assumes the purchase of 1,100,000 shares of Common Stock, par value $.10 per share, at the maximum tender offer price of $4.50 per share in cash.

**

Previously paid.

o

Check the box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number, or the Form or Schedule and date of its filing.

Amount Previously Paid:	Filing Party:
Form or Registration No.:	Date Filed:

o

Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

o

third party tender offer subject to Rule 14d-1.



ý

issuer tender offer subject to Rule 13e-4.



o

going-private transaction subject to Rule 13e-3.



o

amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer: o

Introductory Statement

This Amendment No. 1 ("Amendment No. 1") amends and supplements the Tender Offer Statement on Schedule TO, dated October 10, 2003, relating to an issuer tender offer by Collins Industries, Inc., a Missouri corporation (the "Company"), to purchase up to 1,100,000 shares, or such lesser number of shares as are properly tendered, of its common stock, par value $0.10 per share. The Company is offering to purchase these shares at a price not greater than $4.50 nor less than $3.60 per share, net to the seller in cash, without interest, as specified by shareholders tendering their shares. The Company's tender offer is made upon the terms and subject to the conditions set forth in the Offer to Purchase, dated October 10, 2003 and the related Letter of Transmittal, which, as amended or supplemented from time to time, together constitute the tender offer. This Amendment No. 1 to Schedule TO is intended to satisfy the reporting requirements of Rule 13e-4 under the Securities Exchange Act of 1934, as amended.

In addition to the information set forth below, the information in the Offer to Purchase and the related Letter of Transmittal, copies of which were attached to the Schedule TO dated October 10, 2003 as Exhibits (a)(1) and (a)(2), respectively, is incorporated herein in response to Items 1 through 11 of the Tender Offer Statement on Schedule TO.

ITEM 1. SUMMARY TERM SHEET.

        Item 1 of this Schedule TO and the Offer to Purchase are hereby amended and supplemented by amending the first sentence of the answer to the question "How and When Will I Be Paid" in the "Summary" on page ii of the Offer to Purchase by replacing the words "as soon as practicable" with the word "promptly".

        Item 1 of this Schedule TO and the Offer to Purchase are hereby amended and supplemented by adding the following question and answer to the "Summary" on page ii of the Offer to Purchase:"

        "How Will I Be Notified of the Purchase Price Once It Is Determined?"

        "We intend to issue a final press release to announce the purchase price and proration percentage, if any, within approximately five business days following the expiration date of the tender offer. See "The Offer —Number of Shares; Price; Priority of Purchase.""

        Item 1 of this Schedule TO and the Offer to Purchase are hereby amended and supplemented by adding the following question and answer to the "Summary" on page v of the Offer to Purchase:

        "Will I Be Able to Withdraw Shares That I Have Previously Tendered After the Purchase Price Has Been Determined?"

        "No. You will not be allowed to withdraw tendered shares after the expiration date, regardless of the purchase price that is determined, unless the shares have not been accepted by us for payment by 12:00 midnight, Eastern time, on December 5, 2003. See "The Offer—Withdrawal Rights.""

        Item 1 of this Schedule TO and the Offer to Purchase are hereby amended and supplemented by amending the second paragraph of the answer to the question "Once I Have Tendered Shares in the Offer, Can I Change My Mind?" in the "Summary" on page v of the Offer to Purchase by replacing the date "December 4, 2003" with the date "December 5, 2003".

ITEM 4. TERMS OF THE TRANSACTION.

        The first sentence of Item 4(a) of this Schedule TO is hereby amended and supplemented by inserting the words "Section 5.—Purchase of Shares and Payment of Purchase Price" immediately after the words "Section 4.—Withdrawal Rights".

1

        Item 4(a) of this Schedule TO and the Offer to Purchase are hereby amended and supplemented by amending "Section 1.—Number of Shares; Price; Priority of Purchase," "Section 3.—Procedures for Tendering Shares," "Section 4.—Withdrawal Rights," "Section 5.—Purchase of Shares and Payment of Purchase Price" and "Section 6.—Conditional Tender Procedures" of the Offer to Purchase by replacing, wherever they appear, the words "as soon as practicable" with the word "promptly".

        Item 4(a) of this Schedule TO and the Offer to Purchase are hereby amended and supplemented by amending the first sentence of the first paragraph of "Section 4.—Withdrawal Rights" on page 11 of the Offer to Purchase by replacing the date "December 4, 2003" with the date "December 5, 2003".

        Item 4(a) of this Schedule TO and the Offer to Purchase are hereby amended and supplemented by inserting the following language immediately after the first sentence of the first paragraph of "Section 4.—Withdrawal Right" on page 11 of the Offer to Purchase:

"We will not be able to determine the price and proration percentage, if any, and accept shares for payment until after the expiration date. During this determination, you may not withdraw tendered shares. Once the price and proration percentage, if any, are determined and shares are accepted for payment, they may not be withdrawn. Shares not accepted for payment will be returned promptly."

        The sixth sentence of Item 4(b) of this Schedule TO is hereby amended and supplemented by replacing the words "Section 4.—Procedures for Tendering Shares" with the words "Section 3.—Procedures for Tendering Shares".

        Item 4(b) of this Schedule TO and the Offer to Purchase are hereby amended and supplemented by amending and restating the first two paragraphs under the subsection entitled "Participation" of "Section 11.—Information About Our Shares; Interests of Directors and Executive Officers; Transactions and Arrangements Concerning Shares" on page 19 of the Offer to Purchase as follows:

"PARTICIPATION. Our directors, officers and affiliates are entitled to participate in our offer on the same basis as all other shareholders. Except with respect to our Chairman, Don L. Collins, our Vice President of Marketing, Kent E. Tyler, and one of our affiliates, Collins Capital Corporation, all of our directors, officers and affiliates have informed us that they do not intend to tender any shares into the offer.

        Mr. Collins intends to tender up to 300,000 shares in the offer but may increase the number of shares tendered if proration appears likely. Mr. Tyler intends to tender up to 4,170 shares in the offer. Collins Capital Corporation intends to tender up to 64,922 shares in the offer. Mr. Collins, Mr. Tyler and Collins Capital Corporation have advised us that any tenders made by them are expected to be made at the purchase price determined in the offer rather than at a price selected by them. Accordingly, the effects of such tenders may be:"

ITEM 7. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

        Item 7(b) of this Schedule TO is hereby amended and supplemented by replacing the words "Section 10.—Source and Amount of Funds" with the words "Section 9.—Source and Amount of Funds".

        Item 7(b) of this Schedule TO and the Offer to Purchase are hereby amended and supplemented by deleting the following language from the first paragraph of "Section 7.—Conditions of Our Offer" on page 13 of the Offer to Purchase:

        "(or have been determined by us to have occurred)"

2

        Item 7(b) of this Schedule TO and the Offer to Purchase are hereby amended and supplemented by deleting the following language from the first sentence of the second paragraph of "Section 7.—Conditions of Our Offer" on page 14 of the Offer to Purchase:

        "(including any action or inaction by us)"

        Item 7(b) of this Schedule TO and the Offer to Purchase are hereby amended and supplemented by amending the first sentence of the second paragraph of "Section 7.—Conditions of Our Offer" on page 14 of the Offer to Purchase by replacing the words "sole discretion" with the words "reasonable discretion".

ITEM 11. ADDITIONAL INFORMATION.

        The Form of Election sent to all Restated Tax Deferred Savings Plan Participants in connection with the offer is hereby amended and supplemented by amending and restating item (1) of the participant's representations and warranties found on page 2 of the Form of Election as follows:

        "(1) You acknowledge receiving the Memorandum to Participants in the Collins Industries, Inc. Restated Tax Deferred Savings Plan (the "Plan") and Offer to Purchase memorandum dated October 10, 2003, in connection with the offer by Collins Industries, Inc., a Missouri corporation (the "Company"), to purchase up to 1,100,000 shares of its common stock, $.10 per value per share, at a price not greater than $4.50 nor less than $3.60 per share, net to the seller in cash, without interest."

ITEM 12. EXHIBITS.

(a)(1)	Form of Offer to Purchase, dated October 10, 2003.**
(a)(2)	Form of Letter of Transmittal (including Certification of Taxpayer Identification Number on Form W-9).**
(a)(3)	Notice of Guaranteed Delivery.**
(a)(4)	Form of Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.**
(a)(5)	Form of Letter from Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees to their Clients.**
(a)(6)	Form of Memorandum to Restated Tax Deferred Savings Plan Participants and Election Form.**
(a)(7)	Form of Letter to Shareholders of Company, dated October 10, 2003, from Donald Lynn Collins, President and Chief Executive Officer of the Company.**
(a)(8)	Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9.**
(a)(9)	Press Release issued by the Company, dated October 10, 2003.**
(a)(10)	Election Form for Restated Tax Deferred Savings Plan Participants, as amended.
(a)(11)	Form of Letter to Shareholders of Company, dated November 4, 2003, from Donald Lynn Collins, President and Chief Executive Officer of the Company.
(a)(12)	Press Release issued by the Company, dated November 4, 2003.

3

(b)(1)	Loan and Security Agreement, dated as of May 17, 2002, by and between Collins Industries, Inc. and Fleet Capital Corporation (incorporated herein by reference to Exhibit 10.1 to the Registrant's Report on Form 10-Q for the quarterly period ended July 31, 2002).**
(b)(2)	Amendment No. 1 to Loan and Security Agreement, dated May 17, 2002 (incorporated herein by reference to Exhibit 10.9 to the Registrant's Report on Form 10-K for the annual period ended October 31, 2002).**
(b)(3)	Amendment No. 2 to Loan and Security Agreement, dated December 31, 2002.**
(b)(4)	Amendment No. 3 to Loan and Security Agreement, dated October 9, 2003.**
(d)	Not applicable.
(g)	Not applicable.
(h)	Not applicable.

**

Previously filed.

[Remainder of this page intentionally left blank; signature page follows]

4

SIGNATURES

        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 4, 2003

COLLINS INDUSTRIES, INC.
By:	/s/  DONALD LYNN COLLINS Donald Lynn Collins, President and Chief Executive Officer

5

QuickLinks

ITEM 1. SUMMARY TERM SHEET.
ITEM 4. TERMS OF THE TRANSACTION.
ITEM 7. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.
ITEM 11. ADDITIONAL INFORMATION.
ITEM 12. EXHIBITS.

SIGNATURES

EX-99.(A)(10)

Exhibit 99(a)(10)

Return this form to Mellon
Investor Services no later
November 13, 2003, 5:00 p.m.
(Eastern Time). RETURN THIS FORM OF ELECTION
for shares held in the
Collins Industries, Inc. Restated Tax Deferred Savings Plan (the "Plan")
to Mellon Investor Services
as follows: Do you need assistance?
Call
Mellon Investor Services
at
1-800-414-2879

By Mail:
Mellon Investor Services LLC
Attn: Reorganization Department
Post Office Box 3301
South Hackensack, NJ 07606
By Hand:
Mellon Investor Services LLC
Attn: Reorganization Department
120 Broadway, 13th Floor
New York, NY 10271
By Overnight Delivery:
Mellon Investor Services LLC
Attn: Reorganization Department
85 Challenger Rd-Mail Drop-Reorg
Ridgefield Park, NJ 07660

Plan Account Name Vested Shares as of September 30, 2003

Election Options

I hereby instruct INTRUST Bank, N.A. as Trustee of the Common Stock Fund under the Plan to tender the vested shares credited to my Plan account as indicated below. I understand that my election will apply to the vested shares credited to my Plan account as of the close of business on November 14, 2003, and that the actual number of vested shares credited to my account on that date and tendered by the Trustee may be less than or greater than the shares shown on this form.
Complete Parts A and B below.

PART A - SHARES TO BE TENDERED (choose 1 or 2 below)		PART B - TENDER PRICE (choose 3 or 4)
o 1.	Tender all the vested shares credited to my Plan account	o 3.	Tender my vested shares at a price determined by Dutch Auction (by selecting this option you will maximize the chance of the company acquiring your shares).
o 2.	Tender    % of the vested shares credited to my Plan account (rounded down to the nearest whole number of shares)	o 4.	Tender my shares at the price checked below: (select one) [    ] $3.60                              [    ] $4.10 [    ] $3.70                              [    ] $4.20 [    ] $3.80                              [    ] $4.30 [    ] $3.90                              [    ] $4.40 [    ] $4.00                              [    ] $4.50

You must sign and date below and return this form to Mellon Investor Services by November 13, 2003, 5:00 p.m. (est)

Signature of Plan Participant or Beneficiary

Signature

Date

Telephone Number (Include Area Code)

Important:

By signing this Form of Election and submitting it to Mellon Investor Services, you are agreeing to all of the terms of this form and you are making the following representations and warranties:

(1)

You acknowledge receiving the Memorandum to Participants in the Collins Industries, Inc. Restated Tax Deferred Savings Plan (the "Plan") and Offer to Purchase memorandum dated October 10, 2003, in connection with the offer by Collins Industries, Inc., a Missouri corporation (the "Company"), to purchase up to 1,100,000 shares of its common stock, $.10 par value per share, at a price not greater than $4.50 nor less than $3.60 per share, net to the seller in cash, without interest.

(2)

You are the Plan participant or beneficiary whose account is described in this Form of Election.

(3)

By completing and mailing this Form of Election, you are instructing the Trustee to tender all or a portion of vested shares credited to your Plan account as of the close of business on November 14, 2003, subject to the conditions set forth in the Offer to Purchase. You acknowledge and understand that the actual number of vested shares credited to your Plan account and tendered by the Trustee may be less than or greater than the number of vested shares shown on this Form of Election.

(4)

If you submit an executed Form of Election to Mellon, but do not indicate the number of vested shares you wish to tender, you will be deemed to have tendered, and Mellon will authorize and direct the Trustee to tender, all of the vested shares credited to your Plan account as of November 14, 2003.

(5)

If you submit an executed Form of Election to Mellon, but do not indicate the per share price at which you wish to tender your vested shares, you will be deemed to have tendered, and Mellon will authorize and direct the Trustee to tender, your shares at a price determined by Dutch Auction.

(6)

If you elect to tender vested shares at a price that is lower than the NASDAQ National Market closing price on the expiration date of the offer, the tender price you elect will be deemed to have been increased to the closest tender price that is not less than that closing price. This may result in such vested shares being ineligible for purchase.

(7)

You understand that all authority conferred or agreed to be conferred in this Form of Election shall be binding upon your successors, assigns, heirs, executors, administrators and legal representatives.

(8)

You may not revoke or withdraw a Form of Election once it has been delivered to Mellon Investor Services.

EX-99.(A)(11)

QuickLinks -- Click here to rapidly navigate through this document

Exhibit 99(a)(11)

November 4, 2003

Dear Shareholder:

        On October 10, 2003, Collins Industries, Inc. ("Collins") mailed to all Collins shareholders a letter describing the offer by Collins to purchase up to 1,100,000 shares of its common stock, par value $.10 per share, including the associated preferred share purchase rights, at a price not greater than $4.50 nor less than $3.60, net to the seller in cash, without interest, as specified by shareholders tendering their shares. Enclosed with that letter were copies of the Offer to Purchase by Collins, dated October 10, 2003, the related letter of transmittal, and other related documents.

        On November 4, 2003, Collins amended its Offer to Purchase and Form of Election for Collins Restated Tax Deferred Savings Plan participants by filing a Schedule TO/A with the Securities and Exchange Commission. The Schedule TO/A, a copy of which is enclosed for your reference, contains all of the amendments made to the Offer to Purchase and Form of Election. We encourage each shareholder to read carefully the enclosed materials.

        For additional information regarding the terms and conditions of the offer, see the information contained in the Offer to Purchase (as amended by the enclosed Schedule TO/A) and the letter of transmittal. The Information Agent for this tender offer is Mellon Investor Services LLC. All questions regarding the tender offer should be directed to Mellon Investor Services LLC at (800) 414-2879.

Sincerely,

Donald Lynn Collins,
President and Chief Executive Officer

QuickLinks

Exhibit 99(a)(11)

EX-99.(A)(12)

QuickLinks -- Click here to rapidly navigate through this document

Exhibit 99(a)(12)

PRESS RELEASE

Collins Industries, Inc.	Contacts:	Larry W. Sayre,
15 Compound Drive		Vice President of Finance
Huthinson, Kansas 67502-4349		and Chief Financial Officer
	Phone:	620-663-5551
	For Immediate Release November 4, 2003

COLLINS ANNOUNCES TENDERS BY AFFILIATE AND OFFICER

        Hutchinson, Kansas, November 4, 2003—Collins Industries, Inc. (the "Company") (NASDAQ: COLL) announced today that it has been informed that Collins Capital Corporation, an affiliate of the Company, intends to tender 64,922 Company shares and Kent E. Tyler, Vice President of Marketing, intends to tender 4,170 Company shares in the Company's previously announced modified dutch auction tender offer. These shares represent less than 1% of the total shares of Company common stock currently outstanding. All shares tendered by Collins Capital Corporation and Mr. Tyler will be tendered at the purchase price determined in the offer rather than at a price selected by them.

        The foregoing material may contain forward-looking statements. Forward-looking statements are all statements other than statements of historical fact, including without limitation those that are identified by the use of the words "intends," "anticipates," "estimates," "expects," "plans," "predicts," and similar expressions. We caution that such statements may be subject to a number of uncertainties and actual results could differ materially and, therefore, readers should not place undue reliance on any forward-looking statements. Collins Industries, Inc. does not undertake, and specifically disclaims, any obligation to publicly release the results of any revisions that may be made to any forward-looking statements to reflect the occurrence of anticipated or unanticipated events or circumstances after the date of such statements.

        Collins Industries, Inc. is North America's largest manufacturer of ambulances (including medical attack vehicles, rescue vehicles and fire emergency vehicles), North America's largest producer of Type "A" small school buses, the nation's second largest manufacturer of terminal trucks and a leader in the road construction and industrial sweeper markets. Since 1971, the Company has grown to over 1,000 employees in six plants comprising over one million combined square feet of manufacturing space. The Company sells its products throughout the United States and abroad.

        For more information on Collins Industries, Inc., visit Collins Industries, Inc.'s web site at http://www.collinsind.com.

QuickLinks

PRESS RELEASE