LMC Workholding offers large size power chucks for high-speed applications and extra large thru-holes for large bore lathes.  LMC offers three standard models of large chucks, with larger chuck sizes available by special order. 

The three standard power chuck models include the 18" with 6.5" thru-hole, 21" with 7.5" thru-hole and 24" with 8" to 10.5" thru-holes.  LMC also offers the corresponding thru-hole hydraulic actuator to match the chucks.  According to the company's press release, these chucks offer the quality tolerance needed for large workpiece applications.