When drilling in ferrous metals, blind holes, and especially cutting them in thread, at the bottom remain shavings and sawdust, which is not so easy to remove, especially if the part is massive. “Call” to the aid of the magnet and any steel rod – you can even blunted nail or screw. The terminal will drop to the bottom of the hole, and the magnet attach to the protruding part. Move the lower end of the rod on the bottom, without releasing it from the magnet, and remove from the hole. Sawdust will be at the end of the rod. To be sure, repeat the operation. Similarly, you can get accidentally fallen in tight spaces steel detail.