CHAPTER ONE 12 Bnx-end, Op en- end and Combination Wr enches Box-end and open-end wrenches arc available in set s or separa tely in a variety of sizes. The size number stamped near the end refers 10 the distance between the two parallel flats on the hex head bolt or nut. Box-end wrenches are usually superior to open-end wrenches. Open-end wrenches grip the nut on only two flats. Unless a wrench fits well. it may slip and round off the points on the nut. The box-end wrench grips on all six flats. Both e-poim and lz-poim openings on box-end wrenches are avai lable. The e-poin t gives supe rior hold- ing power; the 12-point allows a shoner swing radius.
Combination wrenches (f igure 23) are open on one side and boxe d on the other. Both ends are the same size. Adj usta ble wre nches ( F i ~ u re 24). However, it can loosen and slip, causing damage to the nut and possibly causing injury. Use an ad- justable wrench only when other wrenches are not avail- An ad jus table wrench fils a variety of nuts or bolt heads able. Adjustable wrenches come in various sizes. This type is undoubtedly the fastest, safest and most f25\ convenient to usc. Sockets that attach to a ratchet handle \::J (Figure 25) are available with 6-point or 12-point open- ings and 114 , 3t H, 1/2 and 3/4 in. drives (f igure 26).
The drive size indicates the size of the square hole that mates with the ratchet handle. Sucket wr enches I{) c> H~ 4C'~~ ........- ~ >.~_ . - Torque w rench A torque wrench (Fi l-: un' 27) is used with a socket to measure how tightly a nut or bolt is installed. Torque wrenches come in a wide price range and in different drive sizes. The drive size is the size of the square drive that mates with the socket. Imp act nrf vc r This tool makes removal of tight fasteners easy and eliminates damage to bolts and screw slots. Impact drivers and interchangeable bits (Ffgure 28) are available at most large hardware stores, tool suppliers and motorcycle deal- ers.
Sockets can also be used with a hand-impact driver. However, make sure the socket is designed for impact use. Do not usc regular hand sockets, as they may shatter.