Hi back,
You must
1) insert spaces into your query
2) remove the second ON keyword from the LEFT JOIN clause

Even if you don't have Access, you can test your queries using Visdate (free application) shipped with VB...

 >sSQLStatement = "SELECT Production.Line, Production.[Part-Number], T12Curr.Steel_Type FROM t12curr " + _
>                "LEFT JOIN Production ON TRIM(t12curr.part) = TRIM(Production.[Part-Number]" + _
>                " AND ON val(t12curr.line) = Production.Line ORDER BY 
                       ^^here
Production.[Part-Number], Production.Line"

HTH