Tariff heading 8426 of Section XVI of First Schedule to the Central Excise Tariff act, 1985, contains "Cranes including Cable Cranes". As per Rule 2(a) of CENVAT Credit Rules, 2004 as amended, all goods falling under Chapter 84 are "Capital Goods".
As per Rule 3 of CENVAT Credit Rules, a provider of output service shall be allowed to take credit of the duty of excise specified in the First Schedule to the Excise Tariff Act, on any capital goods received by the provider of output service on or after the 10th day of September, 2004. The credit so taken may be utilized for payment of service tax on any output service.
Hence, in your case, as per the definition, Cranes used for providing the service of renting them are "Capital goods" as per Rule 2(a)(A)(2) of the rules.
Therefore Excise duty on the same can be utilized for paying Service Tax on the output service of hiring the cranes, subject to other conditions with regard to the invoice, date of taking credit, etc.
Please refer to CENVAT Credit rules in this regard.