To add a length of drillpipe to the drillstring to continue drilling. In what is called jointed pipe drilling, joints of drillpipe, each about 30 ft (9 m) long, are screwed together as the well is drilled. When the bit on the bottom of the drillstring has drilled down to where the kelly or topdrive at the top of the drillstring nears the drillfloor, the drillstring between the two must be lengthened by adding a joint or a stand (usually three joints) to the drillstring. Once the rig crew is ready, the driller stops the rotary, picks up off bottom to expose a threaded connection below the kelly and turns the pumps off. The crew sets the slips to grip the drillstring temporarily, unscrews that threaded connection and screws the kelly (or topdrive) into the additional joint (or stand) of pipe. The driller picks that joint or stand up to allow the crew to screw the bottom of that pipe into the top of the temporarily hanging drillstring. The driller then picks up the entire drillstring to remove the slips, carefully lowers the drillstring while starting the pumps and rotary, and resumes drilling when the bit touches bottom. A skilled rig crew can physically accomplish all of those steps in a minute or two.