For long cuts, rotate the blade in the frame so that the length of the cut is not limited by the depth of the frame. Hold the work with the layout line close to the vise  jaws,  raising  the  work  in  the  vise  as  the  sawing proceeds. To remove a frozen nut with a hacksaw, saw into the nut, as shown in figure 1-26, starting the blade close to the threads on the bolt or stud and parallel to one face of the nut, as shown in view A. Saw parallel to the bolt until the teeth of the blade almost reach the lockwasher. Lockwashers are hard and will ruin hacksaw blades, so do not try to saw them. View B shows  when  to  stop  sawing.  Then,  with  a  cold  chisel and  hammer,  remove  this  one  side  of  the  nut completely  by  opening  the  saw  kerf. Put an adjustable wrench across this new flat and the one opposite, and again try to remove the frozen nut. Since very little original metal remains on this one side of the nut, the nut will either give or break away entirely and permit its removal. To  saw  a  wide  kerf  in  the  head  of  a  cap  screw  or machine bolt, fit the hand hacksaw frame with two blades  side  by  side,  and  with  teeth  lined  up  in  the same  direction.  With  slow,  steady  strokes,  saw  the slot  approximately  one-third  the  thickness  of  the  head of the cap screw, as shown in figure 1-27. Such a slot will permit subsequent holding or turning with a screwdriver when it is impossible, due to close quarters,  to  use  a  wrench. Figure 1-26.-Removing a frozen nut with a hacksaw. Figure 1-27.-Cutting a wide kerf in the head of a cap screw  or  bolt. Hacksaw  Safety The main danger in using hacksaws is injury to your hand if the blade breaks. The blade will break if too much pressure is applied, when the saw is twisted, when the cutting speed is too fast, or when the blade becomes loose in the frame. Additionally, if  the  work  is  not  tight  in  the  vise,  it  will  sometimes slip, twisting the blade enough to break it. CHISELS Chisels are tools that can be used for chipping or cutting metal. They are made from a good grade of tool  steel  and  have  a  hardened  cutting  edge  and beveled  head.  Chisels  are  classified  according  to  the shape  of  their  points,  and  the  width  of  the  cutting edge  denotes  their  size.  The  most  common  shapes  of chisels are the flat (cold chisel), cape, round nose, and diamond  point  (fig.  1-28). The type of chisel most commonly used is the flat cold chisel, which serves to cut rivets, split nuts, chip castings, and cut thin metal sheets. The cape chisel is used  for  special  jobs  like  cutting  keyways,  narrow grooves,  and  square  corners.  Round-nose  chisels make circular grooves and chip inside corners. Finally,  the  diamond-point  is  used  for  cutting V-grooves  and  sharp  corners. As with other tools, there is a correct technique for using a chisel. Select a chisel that is large enough for the job. Be sure to usc a hammer that matches the chisel; that is, the larger the chisel, the heavier the hammer. A heavy chisel will absorb the blows of a light hammer and will do virtually no cutting. Figure  1-28-Types  of  points  on  metal-cutting  chisels. 1-16