fasteners Flashcards
what are designed to chase a damaged external threads but not to cut new threads
die nuts are designed to chase damaged external threads not to cut news threads as they are not adjusted
you should turn the shaft in a lathe while using a thread file to chase threads true or false
false. if you turn the shaft while filing you ALso remove material from the undamaged thread
describe 5 ways of removing a seized bolt
- use penetrating oil if the nut is rusty
- apply heat to loosen thread locking compounds
- use a nut splitter to cut the nut off.
- use a hammer and a chisel to cut the nut off
- use a hacksaw to cut the nut close to the mating thread
what does EDM stand for
eletrical discharge machine
an ÉDM is a good machine for removing studs broken off deep in a hole
true or false
true
thread-restoring inserts can provide stronger threads in soft or weak materials true or false
true
after installation the locking key on a solid threaded insert is broken off true or false
false. they help lock the insert in place
the yield point is reached just before the elastic limit of the fastener material
true or false
false the yield point is just beyond the elastic limit of the fastener material and the lower then tensile strength
bolts are nuts are torqued to a certain preload to keep them tight after the load is added
true
if the bolt threads are enlongated the full tensile load falls on the first one or two threads of the nut
true
a nonheat treated nut is strong enough for most tensioning applications true or false
true
a bolt circle requires a torque of 966ft-lb on each bolt if you use four to one multiplier what is the final toque required on each fastener
268 ft per lb
how is a bolt tensioned in a hydraulic tensioning setup
a jack tool screws onto one end of the bolt which requires some additional thread protruding out of the nut at one end by about 1 to 1 1/2 times the bolt diameter
all lubricants reduce the required torque by the same amount you can use anything true or false
false. different lubriacants reduce the required torque by different ammounts they have different lubricity. only the recomended ones should be used
what is the main purpose of lockwiring
lockwiring is used to prevent fasteners from coming apart and falling into nearby machinery
left handed threaded bolts are lockwired the same as righthand threaded bolts true or false
false all operations referring to cw or ccw should be reversed for left hand threads instead of 2 to 6 oclock the hole postion is 6 to 10 o clock position
the statement that best describes elasiticty
elasticity is the ability to the material to be strecthed and still return to its original shape
applying lubricant to the threads of a fastener
increase the clamp load compared to dry threads
the difference between a screw and a bolt is the
application
why are thread forming screws used
they are convienent in sheet metal assemblies
the pitch diameter of a thread is exactly halfway between the major and minor diameters true or false
false the pitch diameter is diameter of the thread thickness equals the thickness of the space between threads it is approximately half way bewtween the major and minor diameters
on a general purpose iso metric thread what character in the designation indicattes a medium tolerance grade
number 6
name two tapered thread forms
national pipe taper
dryseal national pipe taper fuel
american petroleum institue
the unified thread class that offers the tighest fit
6g
2
4h
3
3
marks on the head of a bolt indicates the
grade and tensile strength
a thread is designated 5/8 - 11 class 2a is a
external thread
the thread angle from an american national thread is
29 degrees
a no go ring gauge is easily by
a annural ring on the knurrled surface
thread camparison gauges used the
pitch diameter
rolled threads are advantageous over machined threads because . they have increased tensile strength
they produce a burnished thread finish
they have a better wear resitance which reduces fatigue and shear problems
true
the three hand taps found in a set are the
taper plug and bottoming
API stands for?
american petroleum insitute
a rivet is
a permanent faster
what is the taper per foot of a tapered gib head key
1/8 taper per foot
what is the taper per foot a tapered dowl pin
1/4 inch taper per foot
name the keys in figure 38
woodruff flat gib head pratt and whitney
