We did our best and can be proud of what we've accomplished.. All of which sounds like a great plan for life, whether "in country" or back in the world. Amtrac Inbound. On the Watery Road Again!!! To Home page. See photos and more concerning the Santa Maria Incident or r ead the Comments of visitors to the site or a tribute to the Marines aboard the Hermitage or of the Corp's Discipline Problems in the s.
Or, perhaps you would just like to see some recent photos of the Corps' Parris Island Training Center or ad some interesting Military Anecdotes from the 60's. Then , maybe you'd just like to see recent photos of the Parris Island Training Center or an array of Links and Things. Equator Crossing. Photo by Richard Landry. Recife, Brazil Christmas Eve, Recife as seen from Olinda, Brazil. Nightime in Recife.
Brazilian Cruzeiros Shellback "Card. Amtrac Warfare. Leave Gearing, Return to Graham County. Guinean troops embark. Guinean troops evacuate Congo. General Dianne Embarks.
Guninean troops fill tank deck. Guinean troops disembark in Conakry, Guinea. After a record making trip up the tricky river, we arrived at Matadi where we embarked over "blue capped" United Nations troops with all of their gear For seven days we fed, entertained and observed our first combat-equipped African Army.
No Adware, Spyware or Pirated software. Home » Freeware Games » America's Army 2. Rating: 45 Player Ratings - Avg. Rating 4. Think again; that is not how the Army works. You are expected to use standard-issue army equipment. You are expected to work closely with your buddies and follow instructions. You are expected to identify your targets before you fire.
Most of all, you are expected to not act like an invincible hero. There are no re-spawns, extra lives or power-ups to find here; when you die in this game, you are out of the round forever! Forget everything you have learned in previous first-person shooters.
Before you can officially begin your career as a soldier, you must do what everyone who has come before you has done: complete boot camp. All the while, you must also do as the Army does and abide to its seven core values: loyalty, duty, respect, selfless courage, honor, integrity and personal courage. A soldier is nothing if he has none of these things. Training does not end once you graduate from boot camp.
In many ways, it will continue on for the rest of your life. Army truly stands for. Best of all, you can experience everything it has to offer for free without any strings attached! Get out there and be all that you can be! Players who complete the SFAS process have the opportunity to take on elite Special Forces roles and are qualified to play in multiplayer missions with units ranging from the elite 82d Airborne Division to the 75th Ranger Regiment.
The game features a number of training missions to get you familiar with the controls as well as learning the roles and weapons of a Special Forces soldier. Other game features include:.
Dave Galvin is a freelance writer and avid gamer. Somehow, he managed to find a way to combine the two passions. The very idea that the United States Army was developing its own in-house game seemed ludicrous. Many people doubted that they had the ability to pull it off. Others thought the whole thing was just rotten to its very core. Regardless of the controversy, it came out and many games and critics alike were ultimately stunned with the final result.
By doing away with many popular first-person shooter conventions, it introduced a more realistic way that those games could be experienced. There are three fastener dimensioning systems that are commonly used in the US: 1. Inch-based fastener dimensioning system dened by ASME standards ; 2.
International metric-based fastener dimensioning system dened by ISO standards. Thread class, t, series and designation within a particular fastener dimensioning system. Material properties, including strength, degree of corrosion resistance, temperature resistance, coating, and toughness. This section discusses how the three fastener dimensioning systems identify fasteners, and how each system denes thread class, t, and series.
It also discusses many of the fasteners that are considered as preferred for design and are available from the Federal Supply System.
Threaded inserts and nonstandard fasteners are also identied here. The markings used on fasteners to identify the fastener material are covered in Section 3 of this chapter.
Most US fasteners use the inch-based fastener dimensioning system for fastener dimensions. This is especially true for fasteners on US Navy ships, systems and equipments. In the inch-based fastener dimensioning system, all fastener dimensions are dened in inches or fractions thereof.
Some US fasteners use the US metric-based fastener dimensioning system for fastener dimensions. These metric fasteners are not always interchangeable with international metric fasteners.
This is because the dimensions of the US metric fasteners are not always the same as the dimensions of international metric fasteners. This is the most commonly used fastener dimensioning system in the world. As part of the global conversion to the international metric SI system, many countries replaced their unique fastener dimensioning systems with the international metric fastener dimensioning system.
All new, and most older, foreign origin systems or equipments use ISO metric standard fasteners. DIN fasteners are completely interchangeable with equivalent size, tolerance class, and material property ISO fasteners. In the international metric-based fastener dimensioning system, all fastener dimensions are dened in millimeters to ISO specications. This terminology differs from the terminology used by both the US and international metric-based fastener dimensioning systems.
Section Standard thread classes have been established in the inch-based fastener designation system to control the amount of tolerance and allowance used in forming threads. Compliance with the established tolerances and allowances ensures that threaded components will be interchangeable. There are six classes of clearance t threads: three for external threads, 1A, 2A, and 3A; and three for internal threads, 1B, 2B, and 3B.
Allowance is specied only for classes 1A and 2A, and the allowance is identical for both classes. Tolerance decreases as class number increases. The tolerance for class 3A is less than that for class 2A, which is less than that for class 1A that is, the higher the thread class number, the tighter the t.
The different classes of threads are distinguished from each other by the amounts of tolerance and allowance specied. Class 1A and 1B threads are intended for use where quick and easy assembly is necessary and where a liberal allowance is required to permit ready assembly, even with slightly bruised or dirty threads.
They are typically used for such applications as the threaded pins in rigging gear, turn-buckles, and other applications requiring thick zinc coatings.
In general, these classes are not commonly used by fasteners on board ship. Class 2A and 2B threads are the most frequently used thread classes for general shipboard applications. They provide a reasonable degree of strength being somewhat stronger than class 1 while having enough clearance to permit application of corrosion-resistant coatings. Class 3A and 3B threads are used in specic applications where closeness of t and accuracy of lead angle are important, such as for adjusting devices and long thread engagements.
They require high-quality production equipment and quality control and provide no allowance for assembly or coatings. Class 3 threads have no clearance at the extreme end of their tolerances and allowances. They are also increasingly used for studs which are set with anaerobic thread-locking compound, for socket-head capscrews, and for elastic stop nuts, where close ts improve locking performance. Class 5 threads are interference t threads and are available in the older NC National Coarse series only.
They are used where the set end of a stud needs to be restrained in its tapped hole against loosening in service or loosening when the nut is removed. Studs with a class 5 t on the set end can have either a class 2 or a class 3 t on the opposite end, as the application requires. Normally, using a class 5 t for the stud set end can be avoided by using a locking compound with a class 2 or class 3 t stud set end see paragraph The t of threads describes the predictable amount of clearance between the external and the internal threads in an assembly.
The t of threads is determined by the class of the internal and the external thread. The thread t ranges from loose, when class 1A and 1B threads are mated, to an actual interference t, where the external thread pitch diameter PD is larger than the internal thread PD with class 5 interference t threads.
Although it is common practice to mate external and internal threads of the same class together, for some applications the requirements for a specic thread t may be met by specifying an appropriate combination of external and internal thread classes. A class 1A external thread, for example, can be mated with a class 1B, 2B, or 3B internal thread to achieve a variety of thread ts.
Class 5 ts present problems in installation, removal and repair unless careful sizing and installation procedures are followed. Wherever temperature limits permit, it is better to use class 3A studs with anaerobic thread-locking compound on the set end. ASME B1. In repair applications, it may be necessary to use studs providing more interference by using thread forms with a slightly larger major diameter.
Guidance on thread interference requirements for repair is discussed in paragraph Five unied screw thread series have been established. Each thread series consists of a series of fastener diameters having a particular distribution of thread pitches. Only four of these ve series are in general use on board ship.
NC is still used for class NC5 t studs and their tapped holes. The most common series is the UNC, or coarse thread series, which makes up the bulk of all threaded fastener production. The eight thread series, 8UN, is the only thread in the constant pitch series in common use for nuts and bolts on board ship. The others are used primarily in pipe unions or special applications.
Differences are: the root must be rounded, the root radius and minor diameter must be inspected within the limits specied and the specied root radii are larger, thus creating a larger minor diameter, There are UNJC and UNJF threads. UNJ series threads are widely used by manufacturers of self-locking nuts. The NC, or National Coarse thread series, has the same pitch as the UNC series, but it is used only for class 5 interference t threads.
See paragraph Two basic concerns are associated with the suitability of a threaded fastener for a particular job: t and function. Whether a fastener will perform its function depends on its physical properties: hardness, tensile strength, proof load capacity, fatigue resistance, ductility.
The fasteners t determines if the fastener can be installed satisfactorily and if there is enough thread engagement and overlap to be Fasteners have to be measured for t and tested for function. Thread gauging is normally the manufacturers responsibility, not the installing activitys responsibility. These systems are thread measuring systems and are used to determine if the various dimensions of both external and internal threads are within acceptable limits; that is, will they t together properly.
Within these gauging systems, only the dimensions listed in paragraph Only three dimensions for external threads and two for internal threads are important in determining proper t. These are: major diameter, functional pitch diameter, and minimum pitch diameter class 3A only for external threads; and functional pitch diameter and minor diameter for internal threads. Unless directed by other guidance, system 21 may be used to check major diameter and functional pitch diameter for external threads, and minor diameter and functional pitch diameter for internal threads.
System 22 may be used to check minimum pitch diameter for class 3A external threads. Except for interference t thread applications, System 21 gauging may be used to determine the acceptability of tapped holes and fasteners for installation in repair actions even when the fastener specications require inspection in accordance with System The following thread gauges are available to identify the threads on inch- based and metric-based fasteners, and are not the thread gauges used to determine the t of the thread: National Stock No.
Includes center gauge with coarse and ne notches. While metric fasteners do have thread classes, they are not the same as the inchbased system thread classes. Instead, the metric-based fastener dimensioning system uses thread t and tolerance parameters that allow a large number of combinations, where the inch-based system uses a limited number of thread classes.
Thread t describes the predictable amount of clearance between the external and the internal threads in an assembly. Metric fasteners dene t using tolerance classes composed of two tolerance values: tolerance grade the tolerance amount and tolerance position. Fasteners can have either one tolerance value that applies to both major diameter and pitch diameter or two tolerance values the rst applies to pitch diameter and the second applies to major diameter.
Tolerance class values are written as tolerance grade followed by tolerance position. This is represented by a number that is added to the tolerance zone designation. The tolerance grades most commonly used for fasteners range from 3 to 9. This number is not an actual toler SCJ-STM ance value, instead it identies the specic tolerance amount to be used based on the fastener diameter range and thread pitch. For example a grade 3 pitch diameter tolerance for a fastener with a pitch diameter between This is the position of the tolerance zone in relation to the fasteners basic size.
It is designated by letters ranging from A to Z except I, K, L, O, Q , where capital letters designate tolerances on internal dimensions such as for nuts and where lower case letters designate tolerances on external dimensions such as for bolts.
The A and a end of the scale designates tolerances that guarantee clearance between external and internal threads. The Z and z end designates tolerances that guarantee interference between external and internal threads. The H and h tolerance designates tolerances that start at the basic size, and increase.
The JS and js tolerance designates tolerances centered on the basic size. The tolerance classes tolerance grade followed by tolerance position most commonly used in the metric-based system are:.
This is used only in the US metric-based system for this purpose. This is used by the international metric-based system where the inch-based system uses 3A. While metric fastener specications allow many different combinations of fastener diameter and thread pitch, there are two major thread series: coarse and ne.
However, the ne series is rarely used, and most metric fasteners use the coarse series. The following is an example of a complete thread designation for a 12 mm diameter external coarse thread fastener, with a t equivalent to 3A.
Identication has sometimes been difficult because the component drawings and logistical support documentation are decient.
Paragraph Use Table for material substitutions. For reactor plant applications, use the appropriate General Reactor Plant Overhaul and Repair Specication for allowed material substitutions. Detailed system and component drawings should identify the fasteners by a military or industry part identication number PIN. This PIN provides enough information to completely identify the required fastener.
However, many system and component drawings do not comply with part identication drawing requirements. Often, fastener hardware is identied only by a general military specication number or by a proprietary manufacturers part number, without identifying the applicable military or industry standard PIN. If the fastener is identied by a military or an industry part number, this number can be crossed-checked directly to a National Stock Number NSN if the part is stocked in the system.
If the part number is not identied on the system or component drawing, review the APL next. In , this policy was modied to only identify maintenance signicant replacement fastener hardware on APLs. Current policy identies maintenance signicant fasteners as fasteners meeting one or more of the following criteria: a. The fastener is part of a pressure boundary in a high energy or critical system where MIC level 1, high shock or weld classication P- 1 requirements apply , b.
The fastener is part of a rotating assembly, c. The fastener is subject to MIC level 1 requirements, The fastener must be replaced when it is removed during maintenance, or e.
The fastener may cause injury to personnel or damage to equipment when it fails. In identifying fasteners on APLs, the component piece number and manufacturers part number should be cross-referenced for those applications in which the standard part number for the fastener is not identied on the component drawing.
Where fastener hardware is identied on APLs, the NSN will be identied in addition to the standard part identication number. When support documentation is inadequate to identify the standard part identication numbers for fastener hardware, the following approach is recommended: a. Obtain the following information about the fastener from the component drawing or by inspecting the fastener: 1. Type fastener: Socket head capscrew, hex-head capscrew, machine bolt, stud, stud bolt, setscrew, etc.
Material and coating: for example, zinc-plated alloy steel, 4. Dimensions: diameter and length, threaded length, 5. For those activities that have access to Fastener Preferred for Design Standards, compare the fastener characteristics identied above with those fasteners listed in the applicable Preferred for Design Standard listed below. These standards have been cancelled due to specication reform efforts, but still can still help to identify inch-based fasteners.
However, they will not help identify preferred metric fasteners because metric fastener preferences were not considered when the standards were last revised. Each Preferred for Design Standard has a table of contents that identies fasteners by type and indicates the section of the document where that type fastener can be found. Each section contains a sketch of the type fastener covered along with applicable standards, material, material strength, protective nish coating , and some of the more important dimensions.
Also listed is the applicable standard part identifying number dash number. Take the following steps to identify a replacement fastener this applies to inch-based fasteners only. Many screws and bolts are identied by the MS num Sometimes more than one dash number may be required to identify the fastener.
Sometimes you will have to refer to the applicable standard to identify the appropriate dash numbers. If a standard part number for the required fastener cannot be located in the Preferred for Design Standard, or the Preferred for Design Standard is unavailable, the next step is to use the Federal Supply Classication to identify the fastener. There are two main ways to access fasteners through the Federal Supply Classication.
The use of these documents is described below. The ASG lists the most commonly used items by class. Less frequently used items may be stocked but not listed in the ASG.
The description of items in the ASG is often incomplete, and reference to the applicable standard may sometimes be necessary to determine if the part is suitable. The applicable standard often consists of an MS number and a dash number, although MS drawings are being replaced by commercial specications in many cases.
Therefore, identication of the standard part number is not required to order the item. This document is more comprehensive than the ASG but more difficult to use.
Classes and alone list approximately 1, standards for screws and bolts. The listing provides only the title of the standard and the preparing activity. Some standards list material and size in the title, but for others it is often necessary to review the document to determine whether it is applicable.
In every case, it will be necessary to review the applicable document to determine if there is a standard part number that can be used to order the required part. Sometimes the specication number can be used as a starting point to identify replacement fasteners. Also, if this is a Military or Federal specication, look in the specications Sec Section 6 usually requires that for military use the fasteners be limited to the variety shown on applicable military or industrial standards and then identies the standards.
In the case of MIL-DTL fasteners, however, this may require viewing the technical requirements for nearly 3, fasteners. In such a case, contact one of the activities identied in paragraph These fasteners are often used in hydraulic systems such as those found aboard submarines and advanced lightweight surface craft, where the space and weight of the components is limited.
The internal hex socket minimizes the size of components, since no space is required outside the bolthead diameter for a wrench or socket. On socket-head capscrews the head is cylindrical, and the sides of the heads are at right degree angles to the surface into which the screw is threaded. For military applications, FF-S requires the capscrews to be manufactured to one of the dimensional standards it lists.
The following dimensional standards are listed in FF-S; some are identied further in Table The replacement capscrews shall be of the same material and nish as those screws previously specied, except as indicated in paragraph The thread forms on the NAS and MS capscrews differ slightly but are interchangeable as long as the number of threads per inch designated as coarse or ne is the same. The reasons for using NAS capscrews for replacement are: a. Since , NAS and NAS capscrews have received a minimum hour bake after plating to provide hydrogen embrittlement relief, whereas most MS cadmium- and zinc-plated capscrews have received only a 3-hour minimum bake.
Some of the MS standards have not been updated to reect current FF-S requirements, or are obsolete The thickness of the cadmium plating on the NAS capscrews is 0. The NAS capscrew threads have a controlled root radius that provides improved fatigue resistance.
Same as MS Package only unless special marking is specied on procurement order Package only unless special marking is specied on procurement order Package only unless special marking is specied on procurement order Package only unless special marking is specied on procurement order. See dimensional specication for complete listing of available thread sizes, diameters, and lengths.
For new designs and replacements use NAS Using this table, you can identify part numbers for replacements for the MS cadmium-plated, socket-head capscrews listed below.
Each NAS standard covers three materials, which are identied in the part number as the following table shows:. The following substitutions are authorized for. NAS and NAS cadmium-plated high-strength alloy steel socket-head capscrews for the equivalent cadmium- and zinc-plated capscrews identied in paragraph When rusting of high-strength alloy steel is a problem, substitution of heat and corrosion resistant A Steel capscrews per NAS and NAS is authorized.
The slightly lower strength is considered to have minimal impact on shock resistance. The part number for the heat-resistant capscrew is the same as for alloy steel except that the dash - in the part number is replaced by an N. This letter N is also found on the head of the fastener for identication purposes. In addition, the last letter of the part number suffix may change to designate a surface nish change.
Heat and corrosion resistant capscrews should be silverplated or have dry lm lubricant per MIL-L applied to minimize the possibility of galling with thread inserts or metals of similar hardness.
The silver plate is designated by the suffix letter 5, as shown in the example in Table Dry lm lubricant should not be applied to heat and corrosion resistant fasteners where the operating temperature is above F. Example of authorized socket head capscrew substitution: Replace MS cadmium plated alloy steel capscrew: a.
Reference to MS or logistic system technical data for MS indicates this capscrew is 1. For applications not subject to MIL-S shock requirements, verify capscrew suitability, using the procedure illustrated in paragraph The lower strength capscrew may be used only if the torque required does not exceed that recommended in Table for the CRES capscrews. Substitution of a black-oxide-coated alloy steel socket-head capscrew for one of any other material or coating except for temporary emergency use.
Socket head capscrews made of different materials and with different coatings may appear similar but have signicant differences in strength and other properties. Therefore, the material and coating should be conrmed by 1 verifying documentation for new screws to be installed and 2 verifying the head marking and magnetic properties in accordance with Table These fasteners are similar to the socket head capscrews identied above but have unique characteristics that prevent their direct substitution for socket-head capscrews.
Only NASM fasteners shall be used for new design; they are preferred for replacement. These bolts have a relatively large radius between the head and the shank for better fatigue resistance, which precludes use of standard at washers. Using a standard washer can induce high stress at the radius between the head and the shank, which will result in bolt failure. Install the bolts with one of the countersunk washers identied in paragraph Because the internal wrenching bolts require countersunk washers, it is important to be able to readily distinguish them from sockethead capscrews.
The capscrews have cylindrical heads. The internal wrenching bolt heads are shaped like truncated cones; that is, the side of the head is tapered, with a larger diameter at the bottom of the head than at the top. The only identication marking on the NAS bolts is an R to indicate rolled threads, although some may be marked with a part number.
The NAS bolts are marked with the part number. The bolts must be used only with one of the countersunk washers identied in paragraph The countersink in the washer must face the head of the bolt.
Except for emergency use, internal wrenching bolts must not be substituted for socket head or hex-head capscrews unless approved by NAVSEA. In general, approval will be limited to applications where drawings and other technical documentation are revised to reect the change.
Another reason for NAVSEA approval is that many of the currently available internal wrenching bolts are not threaded for a sufficient length to use in many hydraulic components, particularly where the bolts are threaded into inserts in aluminum valve bodies.
For military applications, the capscrews must be in accordance with the appropriate military standard see Table When identifying replacement capscrews, be sure that the replacement is as strong as the original. If the strength of the original cannot be determined, select a replacement of the same material with the highest strength. To understand this part number, break it down into its elements and examine each element, as shown in table Applicable standards are:.
Wash hands thoroughly after working with cadmium-plated tools or parts to avoid poisoning from ingestion of cadmium. Do not use zinc or cadmium-plated parts in any hydraulic unit where they may come in contact with hydraulic oil. These coatings react chemically with hydraulic uid to the detriment of system operation. This restriction does not prohibit the use of zinc or cadmium-plated parts such as nuts, bolts, and screws where they are external to the hydraulic unit if there is no danger of uid contamination.
The Grade 8, , psi tensile strength, zinc plated hex head capscrews described in paragraph The use of the Grade 8 zinc plated fasteners are subject to the following restrictions: 1. The fasteners shall not be used in applications where they would be subject to submergence, wet spaces, or the weather.
When replacing a lower strength Grade 2 or Grade 5 fastener with a Grade 8 fastener, the installation torque for the Grade 8 fastener shall be limited to that for the lower strength fastener being replaced. When substituting Grade 8 fasteners for Grade 5 fasteners, use the Grade 5 fastener torque to preload the fastener. Do not use the Grade 8 torque, or you risk damaging the fastened material by applying too much preload. Replacement of Grade 2 or 5 fasteners with Grade 8 fasteners should be treated as a temporary repair, permitted only until the correct grade fasteners can be procured and installed.
The procedures for identifying replacement fasteners, in general, apply to identifying replacement washers. It lists many different types of washers and includes drawings, part numbers and dimensions, which will aid in identifying washers for both new design and replacement. Table identies the at and countersunk washer part numbers that most often apply to hydraulic equipment.
Only cadmium-plated steel washers are included in the table. See table to interpret NAS part numbers. Thread Diameter in. See dimensional standard for complete listing of Thread Types, Diameters, and Lengths. Medium carbon steel Grade 5 0. Part No. Countersunk washers must be used with the internal wrenching bolts described in paragraph The countersunk face of the washer must be placed under the bolt head to prevent the development of damaging stresses at the head-to-shank llet radius of the bolt.
Table lists part numbers for both at plain and countersunk washers one surface to MS alloy steel, cadmium plate. Washers with both surfaces countersunk are usually thicker than washers with only a single surface countersunk. Therefore, do not substitute the two-surface countersunk washers for thinner washers without an engineering analysis to determine that sufficient thread engagement will be maintained.
The double countersunk washers may sometimes be substituted when the available replacement fastener is slightly longer than desired, since the increased thickness may prevent the fastener from bottoming in a tapped hole. Plain hexagon nut machine screw of carbon steel Plain hexagon nut machine screw of carbon steel Plain hexagon nut jam of carbon B carbon steel Plain hexagon nut of grade B carbon steel Plain hexagon nut of grade B carbon steel.
Although lockwashers may be encountered, using the at washers with selflocking nuts, self-locking fasteners, self-locking inserts, or thread sealants such as MIL-S anaerobic compounds is preferable. Follow the procedures in paragraph Also, see Table Standards that contain part numbers for zinc-plated steel nuts are identied in Table , and part numbers for washers in Table These zinc-plated steel nuts and washers are to be used only when the applicable drawings specify this material.
MS No. Nominal Washer Size Inch 0. Thickness Basic , inch 0. Thread inserts are used to restore damaged threads in castings or forgings and to protect and strengthen tapped threads in light materials such as plastic and wood and low-shearstrength metals such as aluminum. Thread inserts are typically used in tapped holes for bolting anges to aluminum valve bodies and valve bodies to aluminum subplates. In repair applications, inserts are used to restore damaged tapped holes or existing damaged inserts previously installed in tapped holes.
The helicalcoil insert Figure consists of a diamond-shaped wire wound in the shape of a helical-coil. The outside diameter of this coil is designed to mate with a drilled and tapped hole sized for each application. The thin wall insert Figure is a bushing with a standard size internal thread and an external thread of a larger standard size for which the mating hole has been drilled and tapped. The helical-coil insert is held in place by the natural spring action of the coil.
The thin wall insert is held in place by expanding the upper two external threads that are serrated to dig into a prepared portion of the hole. Variations are available for both types of inserts with regard to internal thread size and class, internal thread locking features, external locking features to positively retain the inserts, length of inserts, oversized inserts to simplify repair applications, and insert materials.
Figure Typical Thin Wall Inserts The purpose of the following paragraph on helical-coil inserts is to provide a basic knowledge and general instructions on the use of this type insert, as well as the necessary tools and repair kits needed to repair parts with worn or stripped threads. Helical-coil thread inserts are precision formed coils of diamond-shaped wire used as screw thread bushings. They are available in unied coarse, unied ne, taper pipe, 14 millimeter and 18 millimeter metric thread sizes.
The installation process is simple and requires three basic steps: drilling, tapping, and installing; however, it is necessary to have the correct size drills, taps, inserts, and special tools Figure Identication of all of these parts to ensure the correct combination is available for any given installation is beyond the scope of this manual.
Thorough instructions are provided in manufacturers literature as well as in repair kits for a specic thread size and master kits containing several sizes of inserts, taps, and tools. Repair kits, individual inserts, and special taps and tools are available in the stock system for popular thread sizes.
Other helical-coil inserts may also be acceptable. Activities involved in the installation of helical-coil inserts should obtain a copy of technical manual General Installation of Heli-Coil Inserts, U. Air Force T. The thread size of the removed fastener will determine the size of insert and repair kit required. If the insert length needed is different from those supplied in the kits Table , inserts can be bought separately from the manufacturer or the stock system.
See Table through Table A partial listing of available helical-coil inserts is also provided in the Aoat Shopping Guide, Class Determine from the extracted insert whether it was free running or of the screw-locking type. Even in a partially mutilated state, the grip coil of the screw-locking insert can be identied by its non-circular polygonal conguration in the middle section of the insert.
Replace the screw-locking insert only by a screw-locking insert. Screwlocking inserts are usually colored red for identication purposes. Repair kits contain inserts that are usually either all free running type or all locking type. In determining insert size, measuring the length and diameter of the insert in its free state is not an adequate indication of those dimensions of the installed insert. Therefore, the old insert, damaged or otherwise, cannot be measured to determine the full thread depth of the hole.
The tapped hole is used to determine full thread depth. When ordering metric series inserts or repair kits, coarse or ne, also state both diameter and pitch of the threads, such as M18X2. National Stock Number Helical-coil inserts and tools comply with the following standards and specications. Where standard numbers exist to identify individual parts, such as MS , use these numbers in preference to a manufacturers part number See Table through Table This MS included for info only.
MS - Tapped Threads and Assembly. MS - 1. To remove the insert, place the blade of the extracting tool into the hole so that one edge of the blade is one quarter of a turn from the end of the top wire coil.
Strike the head of the tool lightly with a hammer to dig the blade into the top coil of the insert. Bearing down hard on the handle of the tool, turn it slowly counterclockwise maintaining rm pressure on the handle as the insert backs out.
Proper removal of the insert does not damage the parent material. If one or more coils protrude from the hole, cut the wire as close to the surface as possible with wire cutters and then use the extracting tool. Do not reuse inserts once removed, even Whenever an insert is removed, clean the threads of the parent material and inspect for damage. If parent material thread failure is suspected, conduct inspection by gauge. Extracting Tools and Thread Gauges are obtainable from the manufacturers.
Because of the hardness of the insert wire, do not attempt to drill out an insert that needs replacement. Grasp the top coil of the insert with a pair of long nose pliers. Pulling in the direction away from the hole, gyrate the handle of the pliers to free each coil of the insert individually. Once this procedure has begun, do not relieve the pulling force until the insert is fully removed otherwise the parent material threads may be scored and weakened. Using the inserting tool contained in the repair kit, follow the step-by-step installation instructions in the kit.
To remove the insert tang, place the punch type Tang Removal Tool into the installed insert contacting the tang at the bottom of the hole. The tang is snapped off clean by striking the top of the punch a sharp blow with a hammer.
In blind holes, the tang may be removed in the same manner if enough hole depth is provided below the tang with the insert installed. A through hole requires that the insert driving tang be removed.
This is not necessary in a blind hole provided the length of the insert permits the tang to clear the bottom of the screw or bolt when the parts are fully assembled. Retrieve the broken tang and discard. Thread gauges are available to check the tapped hole. The installed insert need not be gauged.
If the tapped hole is tapped correctly, the installed insert will automatically be within the thread tolerance. The insert may not always seat itself when rst installed; however, when a bolt or stud is installed and tightened, the insert will conform to the tapped thread. Oversize inserts, both free running and screw locking, are made of slightly larger wire, and are usually identied by yellow markings on the tang and rst coil.
They are used to repair oversize insert assemblies where an error has occurred in tapping for installation of inserts. Correct out-of-round tapped holes, tapered, and bell mouth conditions by installing oversize inserts.
In replacing oversize inserts, follow the same procedure as for standard inserts, and use the same tools as for the standard insert of the same nominal thread size. Oversize repair kits are supplemental to the regular Unied Coarse and Fine Thread repair kits. Each kit includes a special bottoming tap, instructions, and a quantity of inserts.
Check nal assembly with an appropriate standard thread gauge. If the hole is still oversize, remove insert and repair with a Twinsert.
Twinserts are proprietary to Heli-Coil Products and are special repair inserts for restoring off-center holes, damaged holes, stripped Heli-coil tapped holes, or damaged Twinserts.
A Twinsert assembly Figure consists of two inserts: an outer insert, which is always a free-running type, and an inner insert that may be either a free running or a screw-locking type.
Twinserts are installed in an oversize tapped hole produced with a special Twinsert tap. Installation instructions and part numbers for all kit components are contained in each tool kit. Two diameter length Twinsert sets may be ordered separately. When replacing Twinsert assemblies, remove the inner insert using the extracting tool for standard helical-coil inserts with the same nominal thread size.
Remove the outer insert using the proper extracting tool SCJ-STM for that larger size insert or use long-nose pliers as described in paragraph Break off the driving tang with the Tang Break Off Tool.
Install the inner insert to the position where its top end is ush with the top end of the outer insert Figure Installation is done with the installation tool for standard helical-coil inserts of the same thread size. Remove the tang of the inner insert with the Tang Break Off Tool for the standard coil insert of the same thread size. Stud-Lock helical-coil inserts Figure are an extension of the standard screw-locking insert and are designed to provide higher torque for studs complying with ANSI B 1.
These inserts are designed to provide these torques with inexpensive Class 3A studs and a minimum thread length to engage the complete length of the insert plus one full turn. When using these studs, no additional lubrication is required. Class 5 interference t UNC studs may be used because of the resilient locking chords.
The stud-locking torque is controlled within the proper range for a minimum of three cycles of installing and removing the stud. A new stud may be used for each cycle. In practice, however, the same stud can be reinstalled until the torque falls below minimum, at which point the installation of a new stud will increase the locking torque because the wear is primarily on the stud. Tapped hole preparation is identical to that for standard free-running and screw-locking insert assemblies, the class of t should be 3B.
Installation tools for studlock inserts have a reduced pitch diameter to accommodate the deeper grip coil conguration.
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