Fasteners, Gaskets, Fasteners, Gaskets, Seals, & SealantsSeals, & Sealants

Chapter 9Chapter 9

FastenersFasteners A A fastenerfastener is a hardware device that is a hardware device that

mechanically joins or affixes two or more mechanically joins or affixes two or more objects together. North American fastener objects together. North American fastener production is strongly tied to the production of production is strongly tied to the production of automobiles, aircraft, appliances, agricultural automobiles, aircraft, appliances, agricultural machinery, and other equipment.machinery, and other equipment.

FastenersFasteners BoltsBolts - A (usually) metal fastener consisting of a - A (usually) metal fastener consisting of a

cylindrical body, partially or completely threaded, and cylindrical body, partially or completely threaded, and a larger head; it is inserted into an unthreaded hole a larger head; it is inserted into an unthreaded hole (unlike a screw) up to the head, and a nut is threaded (unlike a screw) up to the head, and a nut is threaded on the other end The size of bolts, etc. is determined on the other end The size of bolts, etc. is determined by three dimensions. The first is the diameter of the by three dimensions. The first is the diameter of the bolt’s threads or the “bolt size". The second is the bolt’s threads or the “bolt size". The second is the number of threads per inch or millimeter. The three number of threads per inch or millimeter. The three primary thread classifications are: fine, course, and primary thread classifications are: fine, course, and metric. The third is the length. The length is normally metric. The third is the length. The length is normally measured from the underside of the bolt head to the measured from the underside of the bolt head to the end of the threaded area. So, the bolt below is 5/16”-end of the threaded area. So, the bolt below is 5/16”-18 x 1.50”18 x 1.50”

FastenersFasteners BoltsBolts – Reverse Threads, or a reverse threaded bolt, – Reverse Threads, or a reverse threaded bolt,

are used from time to time when a normally are used from time to time when a normally threaded bolt or nut might work itself loose. All it threaded bolt or nut might work itself loose. All it means is that instead of turning it clockwise (righty) means is that instead of turning it clockwise (righty) to tighten, you turn it counter-clockwise (lefty). To to tighten, you turn it counter-clockwise (lefty). To loosen a reverse threaded bolt, you turn it clockwise. loosen a reverse threaded bolt, you turn it clockwise.

FastenersFasteners BoltsBolts – – The The tensile strengthtensile strength

is the maximum is the maximum stress that a bolt stress that a bolt can withstand can withstand without breaking. without breaking. This is called the This is called the “GRADE”“GRADE” of the of the fastener. The fastener. The stronger bolt stronger bolt required for the required for the application the application the higher higher “GRADE”“GRADE” bolt is used.bolt is used.

FastenersFasteners NutNut - A nut is a type of hardware fastener with a - A nut is a type of hardware fastener with a

threaded hole. Nuts are almost always used opposite threaded hole. Nuts are almost always used opposite a mating bolt to fasten a stack of parts together. The a mating bolt to fasten a stack of parts together. The two partners are kept together by a combination of two partners are kept together by a combination of their threads' friction, a slight stretch of the bolt, and their threads' friction, a slight stretch of the bolt, and compression of the parts. Different types of nuts:compression of the parts. Different types of nuts:

Castle

Nyloc

Square

Wing Acorn

Flanged

Barrel Lug Hex Tee Peanut Speed

CapSerrated

FastenersFasteners

WASHERSWASHERS Flat WasherFlat Washer – Used under the head of – Used under the head of

a bolt or nut to distribute the forces a bolt or nut to distribute the forces applied when tightening.applied when tightening.

Lock WasherLock Washer – – A washer that is not A washer that is not completely smooth or flat, designed to completely smooth or flat, designed to prevent a nut from loosening. prevent a nut from loosening.

Serrated WasherSerrated Washer – acts as an anti- – acts as an anti-vibration device to prevent the nut vibration device to prevent the nut from loosening during rigorous service. from loosening during rigorous service.

Fender WasherFender Washer - Used under the - Used under the head of a bolt or nut to distribute the head of a bolt or nut to distribute the forces applied when tightening. forces applied when tightening.

FastenersFasteners

Machine Screws - Machine Screws - are similar to regular bolts but are usually smaller in diameter, are threaded all the way up to the head, and the head is often slotted.

FastenersFasteners

Self-tapping screws - or thread cutting screws have sharp threads that cut into a material such as sheet metal or plastic.

FastenersFasteners Torque SpecificationsTorque Specifications - - Most automotive fasteners

have specific tightening requirements. Torque Sequence - The order in which a series of

bolts or nuts should be tightened. This This bolt-tightening-bolt-tightening-sequencesequence is typically used to evenly tension large flat is typically used to evenly tension large flat parts, such as oil pans, valve covers, or cylinder heads, parts, such as oil pans, valve covers, or cylinder heads, to prevent the possible warping or distortion of the flat to prevent the possible warping or distortion of the flat surface while it is being attached with the bolts.surface while it is being attached with the bolts.

1995 ACURA GS CYLINDER HEAD TIGHTENING SEQUENCE

Step torque wrench up in increments:Step torque wrench up in increments: 20 - 40 - 50 - 56 foot-pounds,20 - 40 - 50 - 56 foot-pounds,following the torque sequence at right. following the torque sequence at right. Note: Avoid swivel-joints which will Note: Avoid swivel-joints which will cause the torque to be inaccurate.cause the torque to be inaccurate.

FastenersFastenersRemoving Broken Removing Broken

FastenersFasteners Method 1 – Use a stud extractor Method 1 – Use a stud extractor

or vise grips and grab the or vise grips and grab the protruding end and unscrew the protruding end and unscrew the broken fastener.broken fastener.

Method 2 – Drill a small hole down Method 2 – Drill a small hole down the center of the broken bolt and the center of the broken bolt and use a screw-extractor or easy out use a screw-extractor or easy out to remove the broken fastener.to remove the broken fastener.

Method 3 – Drill out the broken Method 3 – Drill out the broken piece of fastener completely and piece of fastener completely and re-tap new threads in the hole.re-tap new threads in the hole.

Gaskets and SealsGaskets and Seals Gasket - A deformable Gasket - A deformable

material clamped between flat material clamped between flat stationary surfaces to prevent stationary surfaces to prevent the passage of fluids or gasses the passage of fluids or gasses through an opening or joint. through an opening or joint.

Seal - A seal is a device which Seal - A seal is a device which helps join systems or helps join systems or mechanisms together by mechanisms together by preventing leakage (e.g., in a preventing leakage (e.g., in a fluid system), containing fluid system), containing pressure, or excluding pressure, or excluding contamination. They are contamination. They are typically used around rotating typically used around rotating shafts to provide a tight seal.shafts to provide a tight seal.

SealersSealers

Hardening SealersHardening Sealers – for use with – for use with gasketing materials in low gasketing materials in low temperature and low pressure temperature and low pressure applications, such as hose applications, such as hose connections, paper and cardboard connections, paper and cardboard gaskets on permanently mounted gaskets on permanently mounted assemblies.assemblies.

Non-Hardening Sealers - Non-Hardening Sealers - for use for use with or without gasket materials to with or without gasket materials to provide a seal between surfaces on provide a seal between surfaces on semi-permanently mounted semi-permanently mounted assemblies, such as water pumps, assemblies, such as water pumps, valve covers, and intake manifolds.valve covers, and intake manifolds.

More SealersMore Sealers

Anaerobic SealersAnaerobic Sealers – Dry or cure – Dry or cure without the presence of air.without the presence of air.

RTVRTV - Room temperature vulcanizer. - Room temperature vulcanizer. RTV is a silicone glue that solidifies RTV is a silicone glue that solidifies and stabilizes at room temperatureand stabilizes at room temperature

Form-In-PlaceForm-In-Place – or “Gasket Makers” – or “Gasket Makers” seal instantly, forming a reliable, long seal instantly, forming a reliable, long lasting elastomeric rubber gasket that lasting elastomeric rubber gasket that outperforms precut gaskets and do outperforms precut gaskets and do away with the need for gaskets away with the need for gaskets entirely. entirely.

QUESTIONS?QUESTIONS?

Check the textbook chapter 9 for any questions Check the textbook chapter 9 for any questions you still need answered.you still need answered.

Check with at least three other students to try Check with at least three other students to try and find the answers you are missing.and find the answers you are missing.

Finally, Check with the instructor to learn where Finally, Check with the instructor to learn where to go to find the answers you still need.to go to find the answers you still need.