I could have sworn there was such a machine in Journey to the Center of the Earth. Maybe in one of the remakes? And I remember Crack in the World. It scared the dickens out of me as a kid. Anyway, the email:

First, Jonah, there is no earth-boring machine in Journey to the Center of the Earth…James Mason and Pat Boone and Alrene Dahl (like the characters in Verne’s novel) simply folow the trail of an earlier explorer through a series of caves associated with a volcano in Iceland.
Second, giant earth-boring machines are magnificently depicted in the H. G. Wells film “Things to Come” (1936), in the sequence where scientists have supplanted the warlords, leading to a new age of invention, discovery and construction, which climaxes with the scientists shooting their children to the moon in a giant bullet…an unfortunate concept that Wells stole from Jules Verne’s “From the Earth to the Moon” (filmed in 1958 or so with Joseph Cotten).
Third, for a really entertaining take on boring through the earth’s crust, check out the 1965 English film “Crack in the World”, where a team of scientists led by Dana Andrews cleverly shoot a nuke into a deep hole in the earth (somewhere in Africa where the crust is supposedly extra-thin), the idea being that the resulting explosion will allow energy-producing magma to come to the surface, providing heat for electricity. Well, it works, but it also creates a crack in the crust that spreads with devastating consequences in a circle until a chunk of the Earth breaks off and becomes a new moon (while incredibly the lead characters look on in amazement, when they should have been sucked into outer space along with it). Best-laid plans and all that…