I suggest that you don't do this. Nothing good will come from it, will likely ruin or make worse the top ring seal, and could ruin the block. Probably the worst tool ever made.
How do you suggest he get the pistons out if there is a ridge?
It has it's place and must be used sometimes. Used properly it won't ruin a engine block.
And if a ridge reamer needs to be used to get the pistons out then I'd bet it needs to be bored.
FWIW I have done many cheapy engine rebuids and have never regretted any of them. But I have the tools to measure stuff to know if I can get away with it.
