This steel ball is completely custom-made from the drawings provided by the customer and machined to the tolerances that required by the customer. This sphere has a tube welded inside the sphere, and there are reinforcing ribs inside the sphere to improve the compressive strength of the sphere. The customer's design is very reasonable and professional! The maximum size of this sphere that our equipment can process is an inner hole of 1600MM. Welcome new and old customers to browse our website, and welcome to send your technical drawings to us for quotation!