How Drilling Is Different From Reaming

What is a drill?

A drill is a handheld electric tool used to drill holes in materials or parts, and to tighten and unscrew fasteners. The principle of its operation is that the motor converts electrical energy into rotation, and then transfers it to the nozzle. If a drill acts as a nozzle, the drill can be used for drilling, if the bit is used for working with fasteners. Drills are widely used in many areas, including construction, repair work, manufacturing, assembly work, carpentry, etc. Electric drills are divided into two subcategories: impact drills and hammerless drills.

The hammer drill differs from the hammer drill in that it has an additional mode. hammer drilling. The impact is generated by the interaction of the ratchets with the shaft. This allows the drill to tackle hard materials such as stone, brick and concrete. She cannot completely replace the punch, since she lacks power and impact force.

When is it worth choosing a puncher?

• Working with hard materials. The hammer drill is much better at handling stone, concrete and brick. Its percussion mechanism generates an impact force sufficient to drill and destroy concrete, as well as large fragments of stone, showing itself many times more effective than a drill.
• Drilling large holes. The hammer drill can work with large diameter nozzles, which is not the case with a drill. For example, if drills are rarely able to create holes in concrete with a diameter of more than 20 mm, then a hammer drill (using a crown) can drill holes with a diameter of up to 120 mm.
• Dismantling. One of the differences between a hammer drill and a drill is that it has an impact mode without drilling (chiselling). It can be used to remove tiles, plaster from the walls, gouge walls, etc. The drill cannot cope with such tasks. it is not intended for them.

The main differences between an impact drill and a hammer drill

The hammer drill and hammer drill are tools that can partially replace each other. Both are capable of punching holes, working with hard materials, and using impact in their work. For this reason, one often hears questions about how these tools differ in general. Throughout the article, we will analyze what an impact drill and perforator are, what are the features of their design.

What is a puncher?

A hammer drill is also an electric tool, which differs from a drill in the details of its design and the specifics of use. In addition to the rotation of the nozzle, it also gives it a reciprocating motion. To create this movement, a special unit is provided in the perforator: a swinging (drunk) bearing. for straight perforators, and a crank mechanism. for barrel drills. Both units convert rotary motion into reciprocating and interact with a piston that transmits a shock impulse to the nozzle.

Despite the fact that the hammer drill is similar to a drill, it is much more often used for dismantling work and, as a rule, is not used for working with fasteners. This is due to the greater impact force of the hammer drill, its heavy weight, and the lack of chiseling mode in the drill.

Impact drill or hammer drill. what to choose?

In this section, we decided to give examples of the effective use of a rotary hammer and impact drill to make it easier for you to choose a tool for yourself.

The difference between a hammer drill and a hammer drill

A drill and a hammer drill have different mechanisms of impact. The very design of these instruments suggests that they need to be handled differently when using the percussion mode:

• In the case of an impact drill, the operator has to apply additional force, press on the tool. The stronger the impact on the drill, the faster the drilling takes place. But even with maximum effort, the impact force of a drill will be several times less than the lightest perforator.
• When using a hammer drill, force only needs to be applied to hold the tool with confidence. On average, the pressure should not exceed 2-3 kg.

Impact function is basic for a hammer drill. But in a drill, even a percussion one, this is only additional functionality. On the other hand, this makes the drill a versatile and multifunctional tool.

The correct choice of tool should depend on what kind of work you are going to do. In short: a drill is suitable for minor repairs, carpentry, work with fasteners, and a hammer drill is suitable for constant work with concrete, stone and brick, dismantling and chipping walls.

When to choose an impact drill?

• Rare use of tools for drilling small holes. If you need to drill something from time to time, but not too often, there is no point in buying a rock drill. A drill is more than enough to hang a painting, drill through metal, etc. When storing the tool, the drill takes up less space than a hammer drill.
• Working with wood and metal parts. the drill will handle these materials. Wood can drill any tool, and when working with steel or iron, a quality drill plays an important role.
• Tightening and unscrewing fasteners. A drill is much more convenient to work with screws and self-tapping screws, even if it does not have an impact mode. If you use a hammer drill for this purpose, the percentage of rejects. damaged fasteners will increase, and the comfort during work will decrease.
• Preferably work with relatively soft materials. If you do not need to frequently drill concrete, stone or brick walls, then it is quite possible to do without a hammer drill.

Countersinking: tool and features

Countersinking is an intermediate hole making process, usually located between drilling and reaming. This is a semi-finishing hole to:

• increasing hole accuracy up to grade 4 and even grade 5;
• improvement of roughness;
• giving a strict geometric shape.

Also, countersinking is used when machining holes obtained by casting or pressure treatment.

Processing is carried out using a countersink, a tool that looks like a drill, but has a number of design differences. The main differences are the increased bridge between the cutting edges, the increased number of working edges and the cut corner. All this ensures high stability of the countersink and its alignment with the machined hole. So, the presence of 3-4 cutting edges provides a smooth distribution of forces in the zone of contact of the countersink with the workpiece. The geometry of the cutting part allows for machining the hole without metal removal in the longitudinal direction.

Countersinks differ in the number of teeth (3 or 4) and designs. push-on, solid and plug-in. The choice of tool depends on the diameter of the hole. So, the use of plug-in countersinks (with plug-in knives) is recommended for holes with a diameter of 20 mm., Solid ones are used for small diameters (from 12 mm.).

To obtain more accurate and complex surfaces, combined types of tools with a large number of cutting edges (up to 8) are used. In this case, prefabricated countersinks are used in conjunction with other metal-cutting tools. drills, reamers, etc.

Hide Open

Countersinking and countersinking, despite the similarity of names, are different metalworking operations with the corresponding tool. The similarity of operations in the type of processing and the processed surface. Both countersinking and countersinking involve machining by cutting the inner surface of the holes. Differences in the nature of processing and, accordingly, the result obtained.

What is the difference between countersinking and countersinking

Features of countersinking

Countersinking is the machining of holes to create various geometric recesses for the concealed placement of fasteners. It is also used for internal chamfering. For these purposes, there is a special tool. a countersink, which have a different shape. The choice of countersink depends on the desired end result.

The main types of countersinks

Cylindrical countersinks. Used to produce cylindrical grooves in drilled holes for bolts and screws.

Conical countersinks. Used for cutting tapered holes inside the part, as well as for cleaning sharp edges, chamfering and preparing recesses for fasteners. Most commonly used 90 ° and 120 ° tapered tools.

Flat or end countersinks, you can also find the name counterbore. Mainly used for stripping and machining grooves before installing fasteners.

The countersink consists of a working part and a shank with a special trunnion that acts as a guide belt. The trunnion is necessary to control the alignment during the cutting process.

Fundamentals of Reaming

Equipment

For countersinking and countersinking, drilling machines of various types are most often used. A machining center or a lathe can also be used. almost the same equipment on which drilling operations are performed. It is not recommended to use a hand tool for both operations due to insufficient positioning accuracy.

6.6. Drilling and reaming technology

Depending on the required quality and the number of workpieces to be processed, holes are drilled according to a marking or a jig. In the process of work, the following basic rules must be observed:

• when drilling through holes in workpieces, it is necessary to pay attention to the method of their fastening; if the workpiece is mounted on the table, then you need to install it on a lining to ensure free exit to the drill after finishing processing;
• the drill should be brought to the workpiece only after turning on the spindle rotation so that when it touches the surface of the workpiece, the load on it is small, otherwise the cutting edges of the drill may be damaged;

• do not stop the spindle rotation while the drill is in the hole to be machined. First you need to withdraw the drill, and then stop the spindle rotation or stop the machine, otherwise the drill may be damaged;
• in the event of a screeching noise, vibrations occurring during drilling as a result of jamming, skewing or wear of the drill, immediately remove it from the workpiece and then stop the machine;
• when drilling deep holes (l 5d, where I is the depth of the hole, mm; d is the diameter of the hole, mm), it is necessary to periodically withdraw the drill from the hole being machined to remove chips, as well as to lubricate the drill. This significantly reduces the likelihood of breakage of the drill and its premature bluntness;
• it is recommended to drill a hole with a diameter of more than 25 mm in solid metal in two passes (with reaming or countersinking);
• drilling should be performed only according to the modes indicated in the technological maps or in the tables of reference books, as well as according to the recommendations of the master (technologist);
• when drilling holes in workpieces made of steel or viscous materials, it is imperative to use coolant to protect the cutting tool from premature wear and increase cutting conditions.

Drilling by marking is used in one-off and small-scale production, when the manufacture of conductors is economically unjustified due to the small number of processed parts. In this case, marked workpieces with control circles and the center of the future hole applied to them are supplied to the driller (Figure 6.21, a). In some cases, the marking is done by the driller.

Fig. 6.21. Drilling holes according to the marking:
a. marking and punching the center of the hole; b. marking and punching the control circle; в. drift of the drill from the center of the hole; d. correcting the direction of the drill; 1. trace from the center punch; 2. groove from a pre-drilled hole; 3. machined hole

Drilling according to the marking is carried out in two stages: first, preliminary drilling, and then. final. Pre-drilling is done manually by drilling a small hole (0.25d). After that, the spindle and the drill are taken back, the chips are removed, and the alignment of the circle of the drilled hole with the marking circle is checked.

If the preliminary hole is drilled correctly (Figure 6.21, b), drilling should be continued and completed, and if the hole has gone to the side (Figure 6.21, c), then the appropriate adjustment is made: two or three grooves are cut with a narrow chisel (crosscutter) 2 on the side of the center where you want to move the drill (Figure 6.21, d). The grooves guide the drill to the location marked with the center punch. After correcting the offset, continue drilling to the end.

Drilling on the conductor. Various conductors are used to guide the cutting tool and fix the workpiece in accordance with the requirements of the technological process. Permanent fixture mounting bases and drill bushings to guide the drill increase machining accuracy. When drilling along the jig, the driller performs several simple techniques (sets the jig, the workpiece and removes them, turns on and off the spindle feed).

Drilling through and blind holes. In workpieces, there are mainly two types of holes: through, passing through the entire thickness of the part, and blind, drilled only to a certain depth.

The process of drilling through holes is different from the process of drilling blind holes. When the drill comes out of the hole when drilling through holes, the resistance of the workpiece material decreases abruptly. If you do not reduce the feed rate of the drill during this time, then it may jam and break. This happens especially often when drilling holes in thin workpieces, through intermittent holes and holes located at right angles to one another. Therefore, the through hole is drilled at a high speed of the mechanical spindle feed. At the end of drilling, turn off the feed rate and drill the hole manually at a speed lower than the mechanical one.

When drilling with manual feed of the tool, the feed rate should also be slightly reduced before the drill exits the hole, drilling should be done smoothly.

There are three main methods for drilling blind holes.

If the machine on which the blind hole is drilled has some device for automatically turning off the spindle feed rate when the drill reaches a given depth (rulers, dials, hard stops, automatic stops, etc.), then when setting up for this operation, it is necessary adjust to the specified drilling depth.

If the machine does not have such devices, then to determine the achieved drilling depth, you can use a special chuck (Fig. 6.22, a) with an adjustable stop. The thrust sleeve 2 of the chuck can be moved and installed relative to the housing 1 with a drill at a given working depth. The spindle of the machine moves down to the stop of the end face of the bushing 2 against the end face of the jig bushing 3 (when drilling along the jig) or into the surface of the workpiece. Such a chuck provides an accuracy of the hole depth within 0.1. 0.5 mm.

If greater accuracy of the drilling depth is not required and there is no specified chuck, then you can use a stop in the form of a sleeve, fixed on the drill (Fig. 6.22, b), or mark the hole depth on the drill with chalk. In the latter case, the spindle is fed until the drill goes deep into the workpiece to the mark.

Fig. 6.22. Tool for limiting the movement of the spindle feed:
a. a cartridge with an adjustable stop; b. a thrust ring; 1. chuck body with drill; 2. persistent sleeve; 3. jig bushing

The drilling depth of the blind hole is periodically checked with a depth gauge, but this method requires an additional investment of time, since it is necessary to remove the drill from the hole, remove the shavings and, after measuring, re-enter it into the hole.

Drilling holes. Holes with a diameter of more than 25 mm are usually drilled in two passes: first with a smaller diameter drill, and then with a larger diameter.

The diameter of the first drill is approximately equal to the length of the transverse cutting edge of the second drill. This allows you to significantly reduce the cutting force when machining with a larger drill diameter.

When reaming, it is recommended to select the size of the drill according to the smallest hole diameter. You can only drill holes that have been previously drilled. It is not recommended to re-drill holes obtained by casting, stamping, since in these cases the drill drags away greatly due to the misalignment of the hole center with the drill axis.

Rules and techniques for drilling holes are similar to those for drilling.

test questions

• List the basic rules for performing drilling operations on drilling machines.
• Tell us about the features of drilling according to marking.
• How is drilling done using a jig?
• What are the features of drilling through and blind holes on drilling machines do you know?
• What is the order of drilling holes on drilling machines?

The use of countersinks

When using any type of countersinks for work with steel products, it is recommended to use coolant. For cast iron and non-ferrous metals, lubrication is not required. It is very important to choose the right tool for the operation. This takes into account:

• Part material and nature of processing, as well as the location of the hole and the planned number of operations.
• Depending on the method of fastening on the machine, the design of the countersink is selected.
• The choice of tool material depends on the material of the part, the intensity of work, as well as some other factors.

What are these tools in our time

Countersinks of all types are made of high-alloy steel materials, as well as alloys with different cutting angles. Countersinks are divided into different types. It depends on which specific type to apply?

These instruments differ primarily in their design. Their differences depend on the conditions of use on CNC equipment and on machine tools, as well as on GOST. By design, countersinks are divided into the following types.

Occupational Safety and Health

When performing production tasks directly, you should not forget about your own safety, no matter what tool is used with a drill, countersink or countersink.

List of rules and recommendations:

• Work in special clothing, while there should be no twisting threads and scraps of fabric, the buttons should all be fastened.
• Shoes should be closed type, such as shoes or sandals, specially made. You can’t work in shale.
• Protective screen to ensure protection of the entire face against possible swarf ingress.
• Headwear is required.
• Do not work with gloves while rotating the chuck.
• Before work, it is necessary to check the presence of a grounding device and the integrity of the grounding wire.
• Inspect the tool for cracks, chips and burrs to avoid injury.

If in the workplace, in the opinion of the employee, there are health and safety requirements, then you should report this to the management and start work only after obtaining permission.

Countersinking: tool and features

Countersinking is an intermediate hole making process, usually located between drilling and reaming. This is a semi-finishing hole to:

• increasing hole accuracy up to grade 4 and even grade 5;
• improvement of roughness;
• giving a strict geometric shape.

Also, countersinking is used when machining holes obtained by casting or pressure treatment.

Processing is carried out using a countersink, a tool that looks like a drill, but has a number of design differences. The main differences are the increased bridge between the cutting edges, the increased number of working edges and the cut corner. All this ensures high stability of the countersink and its alignment with the machined hole. So, the presence of 3-4 cutting edges provides a smooth distribution of forces in the zone of contact of the countersink with the workpiece. The geometry of the cutting part allows for machining the hole without metal removal in the longitudinal direction.

Countersinks differ in the number of teeth (3 or 4) and designs. push-on, solid and plug-in. The choice of tool depends on the diameter of the hole. So, the use of plug-in countersinks (with plug-in knives) is recommended for holes with a diameter of 20 mm., Solid ones are used for small diameters (from 12 mm.).

To obtain more accurate and complex surfaces, combined types of tools with a large number of cutting edges (up to 8) are used. In this case, prefabricated countersinks are used in conjunction with other metal-cutting tools. drills, reamers, etc.

the engineer will help. Countersink for metal

The countersinking operation can be either the final one in the part manufacturing process, or one of the processing stages before threading. A countersink is usually used to modify a hole in stampings, castings, forgings and workpieces after chiselling, expanding the diameter, after boring with cutters or drilling before subsequent reaming of parts. With this tool, you can get the desired hole profile for fasteners (screws, bolts, self-tapping screws) or process the end surfaces of parts. In the absence of increased requirements for the quality of parts and the need for threading inside the hole, countersinking will be the final operation of the technological process. Countersink helps to remove defects in castings, etc. Roughness indicators increase, geometric inaccuracies disappear, such deviations from alignment, taper and ovality, etc.

Countersinks for metal vary in structure. They are manufactured in one-piece, slip-on, assembled, fitted with carbide teeth, with and without a tapered shank. The countersink is fixed in two ways: using a tapered shank (three-fluted for small diameters) and a mandrel (four-fluted for diameters up to 100 millimeters). High-speed steel is used for the manufacture of countersinks, for the teeth. depending on the destination. For countersinking steel blanks, teeth made of T15K6 alloy are used, for cast iron. teeth made of VK4, VK6 or VK8 material. The cutting inserts are soldered onto the tool. If the teeth are removable, they can be removed for sharpening.

Small countersinks with a diameter of less than 32 millimeters, having three cutting spirals, at first glance resemble a twist drill. Unlike a drill with two flutes, the number of countersink cutting spirals ranges from three to six, and there is no jumper. Several guide strips, according to the number of teeth, contribute to the precise centering of the robust cutting tool. The blades remove metal evenly and efficiently layer by layer, increasing the accuracy class of the bore diameter. For a tool whose material is high-speed steel, the angle of inclination of the cutting part is 45-60 degrees, for a hard alloy countersink. 60-75, a rake angle of 8-15 degrees for steel parts, 6-8 for cast iron and 25-30 degrees for non-ferrous alloys. For a hard-alloy steel countersink, this angle is 0-5 degrees when cutting a steel product, for cast iron it will be 5 degrees. The incline of the cutting edge ranges from 10 to 25 degrees. The chamfer is sharpened on the teeth with a size of 1.2-2.8 millimeters, ensuring the correct direction of the tool.

There are the following types: countersink for cylindrical holes (also called counterbore), countersink for cleaning the ends, cylindrical countersink and conical countersink. When countersinking, we get small recesses in the form of a cone or cylinder, into which bolts or screws with a corresponding head are subsequently screwed in. Countersinking is used for both blind cylindrical holes and through holes.

A more precise machining operation that follows the countersink boring is reaming. The hole in the workpiece during the reaming process is brought to the desired quality before threading. The reamer is an improved model of the countersink by increasing the number of cutters (from six to twelve) and reducing the height of the cut metal layer. The main parts of the tool. the shank, fixed in the machine, and the working part, which is divided into two more segments. cutting and calibrating. The calibrating section also consists of two zones. a conical, in the form of an inverse cone, and a cylindrical one. This design facilitates hole formation and reduces the friction of the reamer against the metal during operation. Cutting occurs with a cutting edge inclined at an angle to the tool axis. Reamers can be solid and mounted, machine (as the name implies. For machine tools) and manual. According to the shape of the holes to be machined, they are conical and cylindrical.

Holes with dimensions not exceeding 50 millimeters can be machined by hand with a cylindrical shank tool. The reamers are fixed on turning units and other machines using a tapered or cylindrical shank. The diameters of the reamed holes are from 3 mm to 10 cm. For large diameters up to 300 mm or for the processing of strong metals, push-on reamers with attachment to the mandrel are chosen. The material for their manufacture is high-speed steel, the teeth are obtained from hard alloys, as well as similar prefabricated countersinks. Solid sweep material. carbon steel.

In the factories of the metalworking industry, countersinking is carried out on different types of machines. drilling and milling, boring and others. First, we outline the starting position for countersinking. To do this, we bore a groove only 5-10 millimeters long in a forging or casting with a cutter. The countersink will subsequently cut this hole much faster than the cutter. For the final countersinking, we use the tool with the same diameter as the diameter of the hole you want to get. In addition to the size, when choosing a countersink, we also pay attention to the type of material from which the workpiece is obtained. Other parameters are also important: the purpose of the product, the volume of production, where the hole will be located, how far we cut in depth, what cutting speed we need and what quality of the surface we want to get. We decide what material our tool should be made of, and with the help of what we will be fixing it on the machine. For small holes in workpieces made of ordinary metal, not of increased strength, it is possible to mount the countersink with a shank, in other cases we securely fix it on a mandrel.

For countersinking, if it will be the final operation of processing a part, we prepare a hole by boring with a cutter or reaming with a drill, taking into account an allowance of 0.8-2 millimeters. We take the diameter of the countersink less than the size of the hole, providing the reamer, for example, cut off the missing 0.02-0.04 millimeters.

When processing steel blanks, in order to avoid strong heating in the cutting zone, we will use coolant cooling. For countersinking the diameter in cast iron or when working with products made of non-ferrous metals, we will not cool the working area.

Terminology

Countersink is a multi-edge cutting tool used when machining holes in metal parts. After machining, conical / cylindrical depressions are obtained, you can create a reference plane near the holes, chamfer at the center hole.

Hole countersinking is a secondary preparation of finished holes for placement of hardware heads. bolts, screws, rivets

Countersink is a cutting tool with a multi-edge surface. It is used in cylindrical / tapered hole machining in workpieces to expand diameter, improve surface characteristics and accuracy. This type of machining is called countersinking. This is a semi-finishing cut.

A. drilling with a drill B. boring on a lathe C. countersinking with a countersink D. reaming with a reamer E, F. counterbiting with counterbores G. countersinking with countersinks H. tapping

Hole countersinking is the process of cultivating the top of an opening to, for example, deburring the edge of a hole or create indentations to hide the head of a rivet or screw and level it with the surface of the part. The device used for this task is called a countersink.

Some requirements that this tool must meet

The selected countersink (according to GOST or according to reference books, or both) must comply with the following technical conditions of use:

Varieties of screws

These fasteners are classified in the same way as self-tapping screws:

• Hat type: semicircular, countersunk, hexagonal, square. However, it should be noted that self-tapping screws have a wider range of caps, so the range of their application is wider.
• Tip shape: blunt (used when screed furniture or plastics), sharp.
• Rod thread: single-start (coarse, frequent, fine), double-start (same or variable height).
• Slots. Like self-tapping screws, they can be cross-shaped, straight, hexagonal.

After the above description of both products, you can combine the data obtained and conduct a comparative analysis that will show how the screw differs from the self-tapping screw. This will help determine which element is more suitable in a particular case.

What is a self-tapping screw?

This is a fastener with a special thread. It is a rod with a head having an external thread. Self-tapping screws are made of stainless or carbon steels. Made in accordance with GOST 27017-86 “Fasteners. Terms and Definitions”. To protect against the corrosive process at the production stage, such products are phosphated, galvanized or oxidized.

Reaming Operation | Machining Operations | Manufacturing Processes

Where is applied?

A special feature of the screw is the fact that it can be used to fasten structures with moving parts. This is possible due to the fact that part of the cylindrical base has no threads.

What are they for?

Self-tapping screws are designed for fastening various structures or their elements to solid foundations. Thanks to their self-tapping ability, they do not require additional measures such as drilling holes. The thread on the self-tapping screws is applied to the entire cylindrical surface of the rod. Thanks to this, a more reliable fixation and fastening occurs.

Varieties of self-tapping screws

Such fasteners can differ in several ways:

• By purpose: for metal, plastic, wood, drywall, etc.
• By type of head: semicircular, cylindrical, countersunk, press washer (used for roofing work), truncated cone, hexagonal (used together with a plastic dowel for attaching heavy objects).
• By the type of tip. The tip of the self-tapping screw can be sharp or made in the form of a drill. Such products are used for fastening metal.
• By type of slot. Simply put, looking like a screwdriver: straight, cross-shaped, hex (furniture).
• By the type of thread. Frequent. for metal and plastic, rare. for woodwork. There are also self-tapping screws with a mixed type thread, most often it becomes less common closer to the head. Such elements are used for fastening structures to concrete bases and are made of high-alloy steels.

It is worth noting that the self-tapping screws for fixing gypsum fiber sheets differ in a special head, it is countersunk and has a thread, directly on the head itself.

What is a screw?

A screw, like a self-tapping screw, is a cylindrical rod with different types of heads and external threads. Designed for attaching various elements to soft bases. Has a head and a cylindrical part, which is partially covered by a thread, which makes it different from a self-tapping screw.

When screwing in the screw, it is necessary to drill a hole with a diameter of up to 70% of the screw thickness. This is the main difference, showing how the screw differs from the self-tapping screw. When working with this fastener, it is important to choose the diameter of the drill in order to properly perform the connection of materials. Screws provide a durable and most often non-separable connection of parts.

How is a screw different from a self-tapping screw? What is the difference?

As you know, various fasteners are present in many products. And most people face it all the time. This is especially true for construction and repair work. So what to use for fixing certain materials or structures? How does a screw differ from a self-tapping screw, what is the difference between these fasteners?

It would seem that at first glance these products are no different from each other. For a long time it was believed that the screw is the prototype of the self-tapping screw. But don’t jump to premature conclusions. Before carrying out repair work, it is better to understand in detail how a screw differs from a self-tapping screw. Photos of these fasteners are presented in the article. At first glance, they are similar, but in fact there are many differences.

How does a screw differ from a self-tapping screw: differences

Outwardly, these fasteners can be very similar, but they have many signs of difference:

• A screw is not as strong as a self-tapping screw, which is made of more resistant alloys and is used to fasten a large number of materials. These include products made of metal or concrete. Therefore, the range of application of self-tapping screws is wider, in contrast to screws. At the same time, hard alloys are not always convenient for some jobs. For example, many craftsmen have noticed that when working with dense materials, sometimes the heads of self-tapping screws are simply cut off. This causes some inconvenience during work. While a screw made of soft material does not break, but simply bends. It is easier to replace it with a new one.

• There is also a significant difference in the manufacturing technology of these fastening materials. All self-tapping screws are heat treated and coated with special compounds.
• Another main difference, showing how a screw differs from a self-tapping screw, is that it cannot be screwed in without pre-drilling a hole. This should be taken into account when carrying out installation work.
• If you look closely, you can clearly see how a screw differs from a self-tapping screw. This is the thread height and pitch. In addition, the thread of the self-tapping screw completely covers its cylindrical part.
• Another external difference is in the tips. With a self-tapping screw, it is always sharper. However, in rare cases, there are also screws of this kind.