The bar stock cutter performed well when cutting the steel concrete 

 reinforcing bar. It is not suitable for cutting wire rope and angle 

 iron because of the configuration of the cutting head. It tends to 

 smash these items without cutting them. The bar stock cutter is also 

 a single-acting hydraulic cylinder and should be stored with the jaws 

 closed . 



OPEN CENTER HYDRAULIC EQUIPMENT 



Hydraulic tools and equipment with an open center valve configura- 

 tion require two hydraulic hoses. The hydraulic fluid flows from the 

 power source to tool and back to the power source whenever the power 

 source is operating. Actuating the tool trigger or handle blocks the 

 fluid bypass at the tool and directs the fluid through the tool hydraulic 

 motor . 



Diesel-Driven Hydraulic Power Unit 



The diesel-driven hydraulic unit (see Figure 22) used with the 

 open-center hydraulic salvage tools was built at NCEL. This unit has a 

 variable hydraulic output from two to ten gpm and develops a maximum 

 pressure of 2000 psi. This type of unit is being evaluated for use with 

 hydraulic tools at depths generally less than 300 feet. This hydraulic 

 unit was used with an open-center cutter (2 gpm), a winch power handle 

 (6.5 gpm), and a hacksaw (4 gpm) for the test program. The flow rate 

 (gpm) to the tool is controlled by a bypass flow regulator. This method 

 of flow control is preferable because a flow rate can be supplied to the 

 tool when a minimum of hydraulic power is converted to heat. The hydrau- 

 lic unit performed very well during the tool tests. A detailed descrip- 

 tion and evaluation of this unit will be included in a future NCEL pub- 

 lication on power sources. 



Cutter 



The open-center cutter shown in Figures 23 and 24 weighs 27 pounds 

 in water. It is designed to operate at 1 to 3 gpm and at pressures to 

 1800 psig. This commercial tool was designed for underwater cutting of 

 wire rope and bar stock. 



The purpose of evaluating this cutter was to determine its perform- 

 ance and any diver handling problems. The underwater tests for this 

 cutter consisted of cutting wire rope and other materials. The results 

 of these tests are shown in Table VII. 



25 



