This post is not about the best way to remove rusted in bolts that retain the inserts in the holder. Die casters who are running dies that are constructed using metric bolts have enough practice to teach me more efficient ways. The hot steamy die cast running environment is perfect for generating enough rust to seize a bolt in one casting run

In North America most die casters still use coarse thread cap screws to secure inserts within the holder. This is because they spin free even when rusted in. Yes it is going to take a 10 ft pipe and possibly lifting with the crane. This is more time efficient than drilling. My first experience with metric bolts was a European transfer die. Converting this die to US coarse bolts was the right answer for a single die. Converting an entire plant of metric secured dies is cost prohibitive.

I did not know of a good solution until I worked building Japanese designed excavators. They use soft Loctite on all bolts because it becomes impossible to drill out rusted in metric bolts in the field when service is required. The same Loctite is effective on preventing metric bolt seizing in die cast dies