On a front of the chuck you should have a silver colour nut - this is no 16mm. Use a spanner no 16mm (metric one) to unscrew the chuck without the hummer. But I'm afraid not every chuck have the nut on the front.
On a front of the chuck you should have a silver colour nut - this is no 16mm. Use a spanner no 16mm (metric one) to unscrew the chuck without the hummer.
On a front of the chuck you should have a silver colour nut - this is no 16mm. Use a spanner no 16mm (metric one) to unscrew the chuck without the hummer. But I'm afraid not every chuck have the nut on the front.