framing or sheathing work; finish nailers are used for paneling or trimming. There is also a wide variety of staplers that you can use for jobs, such as fastening sheeting,  decking,  or  roofing.  These  tools  are  often driven by compressed air. The amount of pneumatic, or air, pressure required to operate the tool depends on the size of the tool and the type of operation you are performing.  Check  the  manufacturer’s  manual  for  the proper air pressure to operate the tool. The  power  nailer  and  power  stapler  are  great timesaving tools, but they are also very dangerous tools. Observe the following safety precautions when using  them: Use the correct air pressure for the particular tool and job. Use the right nailer or stapler for the job and also the correct nails and staples. Keep  the  nose  of  the  tool  pointed  away  from your body. When you are not using a nailer or stapler or if you  are  loading  one,  disconnect   the   air supply. MATERIALS LEARNING  OBJECTIVE:  Upon  completing this section, you should be able to identify the types,   sources,   uses,   and   characteristics   of the   common   woods   used   on   various construction  projects. Of all the different construction materials, wood is probably the most often used and perhaps the most important. The variety of uses of wood is practically unlimited.   Few   Seabee   construction   projects   are accomplished without using some type of wood. It is used  for  permanent  structures  as  well  as  concrete forms, scaffolding, shoring, and bracing, which may be  used  again  and  again.  The  types,  sources,  uses, and  characteristics  of  common  woods  are  given  in table 3-1. The types of classifications of wood for a large  project  are  usual]  y  designated  in  the  project specifications  and  included  in  the  project  drawings. Table  3-1.-Common  Woods TYPES SOURCES USES CHARACTERISTICS Oars, boat thwarts, benches, Strong,  heavy,  hard,  tough,  elastic, gratings,   hammer   handles, close   straight   grain,   shrinks   very ASH East of Rockies cabinets,   ball   bats,   wagon little, takes excellent finish, lasts well construction,   farm   imple- ments Cabinetwork,   imitation Similar  to  birch  but  not  so  durable East of mahogany   furniture,   wood when exposed to weather, shrinks and Mississippi  and dowels,  capping,  boat  trim, checks   considerably,   close   grain, BEECH southeastern interior finish, tool handles, light  or  dark  red  color Canada turnery, shoe lasts, carving, flooring East of Cabinetwork,   imitation Hard,  durable,  fine  grain,  even Mississippi River mahogany   furniture,   wood    texture,  heavy,  stiff,  strong,  tough, and north of gulf dowels,  capping,  boat  trim, takes high polish, works easily, forms BIRCH coast states, interior finish, tool handles, excellent   base   for   white   enamel southeast turnery, carving finish, but not durable when exposed. Canada, and Heartwood  is  light  to  dark  reddish Newfoundland brown in color 3-21