Exhibit 31aCERTIFICATION

I, Michael E. Batten, certify that:

|1. | I have
      reviewed this quarterly report on Form 10-Q of Twin Disc,
      Incorporated;                                                                                                                                                                                                                                                                        
|-- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|  
|2. | Based on my
      knowledge, this report does not contain any untrue statement of a material
      fact or omit to state a material fact necessary to make the statements
      made, in light of the circumstances under which such statements were made,
      not misleading with respect to the period covered by this report;                                
|  
|3. | Based on my
      knowledge, the financial statements, and other financial information
      included in this report, fairly present in all material respects the
      financial condition, results of operations and cash flows of the
      registrant as of, and for, the periods presented in this report;                                                   
|  
|4. | The
      registrant's other certifying officer and I are responsible for
      establishing and maintaining disclosure controls and procedures (as
      defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal
      control over financial reporting (as defined in Exchange Act Rules
      13a-15(f) and 15d-15(f)) for the registrant and have:
|  
|   | a)                                                                                                                                                                                                                                                                                                                                                                
|  
|   | b)                                                                                                                                                                                                                                                                                                                                                                
|  
|   | c)                                                                                                                                                                                                                                                                                                                                                                
|  
|   | d)                                                                                                                                                                                                                                                                                                                                                                
|  
|5. | The
      registrant's other certifying officer and I have disclosed, based on our
      most recent evaluation of internal control over financial reporting, to
      the registrant's auditors and the audit committee of registrant's board of
      directors (or persons performing the equivalent function):                                                
|  
|   | a)                                                                                                                                                                                                                                                                                                                                                                
|  
|   | b)                                                                                                                                                                                                                                                                                                                                                                
|  

Date: May 7, 2008
    
    /s/
      MICHAEL E. BATTENMichael E. BattenChairman, President and Chief Executive Officer


---