Introduction to Limits and Fits
The 3 basic types of fits are:
clearance, transition, interference
Which system involves creating computer models defined by geometrical parameters?
CAD
The difference between a screw and a bolt is the:
length
application
class of thread
head shape
application
Which material condition is allowance based on?
MMC (maximum material condition)
What was CAD originally referred to as?
computer aided drafting
What is the type of fit where the hole is always larger than the shaft?
clearance
The first source of CAD resulted from attempts to do which of the following?
automate the drafting process.
automate the CNC process.
automate the simulation process.
automate the machining process.
automate the drafting process.
Cap screws are:
precision screws
also called machine bolts
the same as machine screws
square headed
precision screws
Which system uses geometrical design data to control automated machinery?
CAM
What is the type of fit for a shaft with the following dimensions?
Shaft 1.996"/1.994", Hole 1.993"/1.992"
interference
What is the tolerance of 1.500" +/- 0.003"?
0.006"
What does CADD stand for?
computer aided design and drafting
Marks on the end of a bolt indicate the:
class of fit
grade and tensile strength
pitch of the thread
number of turns before the bolt is tight
grade and tensile strength
What is the allowance for a hole/shaft pair with the following dimensions?
Shaft 1.996"/1.994", Hole 1.993"/1.992"
-0.004"
Dowel pins are:
made from dowel stock
made from brass
hardened and ground
painted for identification
hardened and ground
If a shaft is 85.05mm +/- 0.05mm and the hole is 85mm +/- 1mm, what is the type of fit?
transition
What does CIM stand for?
computer integrated manufacturing
Thread forming screws are used because:
they are light
they have a pleasing appearance
they are convenient in sheet metal assemblies
they are small
they are convenient in sheet metal assemblies
When a heavy load is transmitted between a shaft and pulley, use a:
heavy duty Woodruff key
Gib head tapered key
heavy duty square key
Pratt and Whitney key
Gib head tapered key
Calculate the limits of size for 1.875" +/- .010"
1.885"/1.865"
What is the type of fit where the hole is always smaller than its mating shaft?
interference
What are 3 disadvantages of CAM.
- high start up cost
- cost to maintain software including upgrades can be high
- loss of high level manual skills
If the major diameter of a screw is 0.190 inch, and the pitch is 24, what is the designation of the screw?
10-24
8-32
10-32
12-20
10-24
An external tooth lock washer:
provides more friction than an internal lock washer of the same size
provides the same friction as an internal tooth lock washer of the same size
is used only with 82 degree flat head screws
provides less friction than an internal lock washer of the same size
provides more friction than an internal lock washer of the same size
Developments in CAD were pioneered by which of the following?
NASA Research Laboratories
Ford Motor Company Research Laboratories
General Motors Research Laboratories
Chrysler Research Laboratories
General Motors Research Laboratories