Non-threaded fasteners and locking devices (160103g) Flashcards
A rivet is:
a permanent fastener.
What is a taper per foot of a tapered gib head key?
1/8 inch taper per foot
What is the taper per foot of a tapered dowel pin?
1/4 inch taper per foot
Why are rivets used? And what type of materials are they used on.
Rivets are useful for quick, low cost joining and repair of sheet metal, plastic, fabric and belting and where bolts or screws would be impractical.
What type of material is coil type inserts used on? Explain the reason they are used.
Used on aluminum castings, making the threads harder, tougher, smoother and more wear-resistant.
What is the most common rivet used and give a brief description?
Semi-tubular rivets have short tubular bores that have all the compressive strength and shear strength of solid rivets when they are clinched.
How should a key fit a shaft? How much clearance on the top of key to hub?
The key should be a tight fit into the keyway and keyseat. The key should have 0.002-inch to 0.005-inch clearance on top and fit tight on the sides.
What size shaft is a flat key used on?
Flat keys are used on shafts over 6 inches.
What key would you use on a 3” shaft?
Square key
What key is used when the hub slides on the shaft?
Pratt and Whitney keys
What material would you not use a gib head key?
Cast iron
What are dowel pins not used for?
Not for holding the parts in place
What are the 2 reasons to use tapered dowel pins?
- When precise location is required
- When frequent assembly and disassembly is needed
Shear pins are designed to break. Give 2 reasons why.
- To prevent overloads in drive mechanisms
- For safety purposes
Is it recommended to reuse cotter pins?
No
What kind of washer is used in bearing assembly’s where positive location is important?
Tab washer
Where are beveled washers used?
Beveled washers are common with structural steel components, such as I-beams.
How does Anaerobic sealant work?
When exposed to air, aerobic sealants cure to form a firm flexible rubberized seal.
How much taper does a tapered dowel have per foot?
1/4 inch taper per foot
How much taper does a gib head key have per foot?
1/8 inch taper per foot
With a bolt having a tensile strength over 150000 psi, what nut would you use?
High carbon heat-treated nut, Grade 8 and higher
Which thread has the greatest strength, a fine or course thread?
Coarse thread
What is the purpose of wire locking?
Lockwiring is used to prevent fasteners from coming apart and falling off into nearby machinery.
What is the purpose of thread restoring inserts?
To restore damaged or stripped threads and to provide strong threads in soft or weak materials
