Exhibit 5.1
November 28, 2008
WSI Industries, Inc.
213 Chelsea Road
Monticello, MN 55362
Re: Opinion of Counsel as to Legality of 200,000 shares of Common Stock to be
Registered under the Securities Act of 1933
Ladies and Gentlemen:
This opinion is furnished in connection with the registration under the Securities Act of 1933 on
Form S-8 of 200,000 shares of Common Stock, $0.10 par value per share, of WSI Industries, Inc.,
(the “Company”) offered to executives and other key employees, consultants and directors of the
Company or its subsidiaries pursuant to the WSI Industries, Inc. 2005 Stock Plan (the “Plan”).
As general counsel for the Company, we advise you that it is our opinion, based on our familiarity
with the affairs of the Company and upon our examination of pertinent documents, that the 200,000
shares of Common Stock to be offered to employees, directors and consultants under the Plan will,
when paid for and issued, be validly issued and lawfully outstanding, fully paid and nonassessable
shares of Common Stock of the Company.
The undersigned hereby consent to the filing of this opinion with the Securities and Exchange
Commission as an Exhibit to the Registration Statement with respect to said shares of Common Stock
under the Securities Act of 1933.
Very truly yours,
LINDQUIST & VENNUM P.L.L.P.
/s/ Lindquist & Vennum P.L.L.P.
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