If cost is a concern, then just using off-the-shelf bearing balls is almost certainly a good choice. They’re mass-produced in such volume that I doubt you can find cheaper small hardened steel objects with reasonable drag properties
Those look some of the extremely common 4-5mm hardened steel bearings. All of them in that grenade are likely less than 1 euro. Looks like they are embedded in resin. The resin likely cost as much.
If you don’t care about precise size, balls can be made cheaply by dropping drops of metal down tower where they are cooled by air as they fall, and then by water after they solidify. Then just sort by size
If cost is a concern, then just using off-the-shelf bearing balls is almost certainly a good choice. They’re mass-produced in such volume that I doubt you can find cheaper small hardened steel objects with reasonable drag properties
Those look some of the extremely common 4-5mm hardened steel bearings. All of them in that grenade are likely less than 1 euro. Looks like they are embedded in resin. The resin likely cost as much.
If you don’t care about precise size, balls can be made cheaply by dropping drops of metal down tower where they are cooled by air as they fall, and then by water after they solidify. Then just sort by size