When we think of the typical application of the clamshell (split-frame) lathe, we picture it being used as an OD mounted tool (split , reassembled around and clamped to the outside diameter of a pipe). The truth is, a split-frame can be turned “inside out” and the mounting elements, comprised of jack screws and mounting pads, can be arranged so as to project outwardly from the machine. The tool holders must also be turned 180º to face outwardly – with their hex key recesses facing inward.
Keep in mind that for this to work, the normal size range of the machine would be drastically different. In other words, if you are using a clamshell designed to fit around and machine 30” pipe (from the outside), you would have to use a much smaller clamshell to fit in and cut outwards from the 30” ID bore.
If you need to cut from the inside out, the best thing to do is to contact your sales representative and they will assist with configuring your equipment or arranging a rental of the machine and tooling you would need to perform this unique machining.