This is hilarious, but probably not viable: a) Coffins are sold to grieving families on the basis of "the one last thing you can do for [deceased]". Hence sal

This is hilarious, but probably not viable: a) Coffins are sold to grieving families on the basis of "the one last thing you can do for [deceased]". Hence sales are made based on how luxurious, etc. the coffin is, not how efficiently it bores into the ground. b) Who is going to want to file past a gigantic drill bit in a church? c) If you look at the silhouette in fig 6, the coffin is roughly 40% longer than the deceased. Hence to bury a 6 foot tall individual, the coffin will need to be ~ 8.5 feet long, too tall to be screwed in by hand. d) Part of the point of burials is the ceremony of lowering the coffin into the grave. This won't be viable with the screw coffin - "alright folks, it's time to bury Dad. Now these two hefty blokes are going to take a quarter of an hour to screw him into the ground. You all stand there and listen to him bump around inside the coffin".