PLEASE READ BEFORE PURCHASING!
Regarding the mounting holes on the casters are shaven as described in the product page, the mounting holes are heavy, so please be aware that you have extended processing before purchasing.
Regarding how to install, if you tighten it completely from the beginning, the other three holes will not match, so you can temporarily secure one place.
Then temporarily secure the bolt to the hole on the face or diagonally and temporarily hold all 4 places.
If they do not tighten them completely, they will enter all 4 bolts, and then gradually tighten them up.
Drilling may be required due to individual problems.
If the hole does not fit even after diagonal tightening, please use the expansion process.