Originally Posted by axis  ....and you may want to see if the gt20 has the wiring for a barfeeder i think you can only use a bar puller |
If you are bar feeding or pulling you need the hydraulic chuck option. You can easily build your own bar feed operating from the user M functions. We have three shop built hydraulic bar feeds that use the machine coolant to push the bar stock forward like a piston. One has a pressure tank that is filled with coolant through a one way valve from the regular coolant pump and is pressurized with 100 psi air to do the feeding. The air supply to the pressure tank is interconnected with the air that opens the chuck. The other two have separate hydraulic pumps and motors. The regular coolant pump supplies coolant to the hydraulic pump through a standard hydraulic filter. To feed the bar the user M code operates a relay to turn on the hydraulic pump motor just before opening the chuck.
On the two machines with separate pumps it is possible to feed the bar with the spindle running and this saves a few seconds per part over pulling because there is no wait for the spindle to stop and restart.