The screws for the needle plate strip easily. Watch out when when you take them out and don't over tighten them.
THIS! On almost *EVERY* industrial sewing and/or embroidery machine ever made. A shallow slotted screw or 2.5mm hex screw into cast iron...what could go wrong?
And there is almost never enough meat in the casting to tap next size or helicoil. Definitely an afterthought on the part of engineering, per usual.
To be fair, these are complex machines trying to perform repeated precision tasks in cramped spaces. Basically giant cast iron pocket watches. There are better fasteners, but sewing in general follows very traditional tooling methods. Most any factory in the world has slotted screw drivers lying around, and *maybe* a set of hex keys.
I have an Adler cylinder arm sewing machine at home that uses stainless torx screws for almost everything and I LOVE IT.