Punch Tool

A punch is a hard metal rod with a shaped tip at one end and a blunt butt end at the other, which is usually struck by a hammer. Most woodworkers prefer to use a ball-peen hammer for using punches. Punches are used to drive objects, such as nails, or to form an impression of the tip on a workpiece. Decorative punches may also be used to create a pattern or even form an image.

• Nail or pin

A nail punch also called a nail set, is used to drive the head of a nail flush with or below a surface. A pin punch is a similar tool used to drive pins for affixing a fixture to a rotating shaft. Nail and pin punches have a body by which the punch is held, with a flat ended cylindrical section whose diameter suits the object to be driven into the wood.

• Center

A center punch is used to mark the center of a point. It is usually used to mark the center of a hole when drilling holes. A drill bit has the tendency to "wander" if it does not start in a recess. A center punch forms a large enough dimple to "guide" the tip of the drill bit. When drilling larger holes, and the web of the drill is wider than the indentation produced by a center punch, the drilling of a pilot hole is usually needed.

An automatic center punch operates without the need for a hammer.

• Prick

A prick punch is similar to a center punch but used for marking out. It has a sharper angled tip to produce a narrower and deeper point. It is also known as a Dot punch. The mark can then be enlarged with a center punch for drilling.

• Transfer

A transfer punch is a punch (usually in an index set) of a specific outer diameter that is non-tapered and extends the entire length of the punch (except for the tip). It is used to tightly fit the tolerances of an existing hole and, when struck, precisely transfer the center of that hole to another surface. It can be used, for example, to duplicate the hole patterns in a part, or precisely set locations for threaded holes (created by drilling and tapping) to bolt an object to a surface.

• Doming

A doming punch is used in conjunction with a doming block to make spheres or hemispheres out of sheets of metal. The punch is generally made of tool steel, but can be made of wood. They come in a number of different sizes, the punch size determining what size the finished product will be.

• Drift

A drift "punch" is misleadingly named; it is not used as a punch in the traditional sense of the term. A drift punch, or drift pin, or lineup punch, is used as an aid in aligning bolt or rivet holes prior to inserting a fastener. A drift punch is constructed as a tapered rod, with the hammer acting on the large end of the taper. The tapered end of a drift punch is placed into the semi-aligned bolt holes of two separate components, and then driven into the hole. As it is driven in, the taper forces the two components into alignment, allowing for easy insertion of the fastener. Unlike most punches, force is never (and should never be) applied to the tip, or end of a drift pin.

• Roll Pin

Roll Pin Punches are used to drive roll pins. Standard Pin Punches should NEVER be used on a roll pin. Because of the hollow, thin wall construction of a roll pin, a standard pin punch will often collapse,mar or distort the end of the pin or be driven into,and jammed inside, the hollow core of the roll pin. When choosing a Roll Pin Punch, select one that is no larger than the compressed diameter of the pin. If a punch is used that is larger than the pin,the surrounding metal in which the pin is seated can be damaged.Also, a Roll Pin Punch should not be used which is smaller than the compressed diameter of the pin. If this occurs, it may be possible to drive the punch through the hollow center of the roll pin.

Roll pin punches are designed with a small projection in the center of the pin tip to support the circumference of the roll pin. The tips of Roll Pin Punches are NOT FLAT and should NEVER be used on regular solid pins. If a roll pin punch is used on a solid pin, it will mar or mark the pin.

If the end of a Roll Pin Punch is damaged or deformed, it should be discarded. It is virtually impossible to regrind the tip of the roll pin punch and properly shape the center projection. When using a Roll Pin Punch, make sure the axis of the shank of the Roll Pin Punch is in line with the axis of the roll pin. DO NOT cant the Roll Pin Punch off to one side.When you strike the Roll Pin Punch, hit it directly on the top of its head. If you strike the head of the Roll Pin Punch at an angle you may bend the shank.

• Letter

Also known as letter stamps or number stamps. These are used to emboss the impression of a letter or number into a workpiece. They are most common in the reverse image, this allows the end result to be immediately readable, however they may be made as a positive image. This is essential in the case of die or mold making and ensures that the finished product will be readable, as a die is a negative image.

Symbols And Conventions Used In Welding Documentation

The symbols and conventions used in welding documentation are specified in national and international standards such as ISO 2553 Welded, brazed and soldered joints -- Symbolic representation on drawings and ISO 4063 Welding and allied processes -- Nomenclature of processes and reference numbers. The US standard symbols are outlined by the American National Standards Institute and the American Welding Society and are noted as "ANSI/AWS". Due in part to the growth of the oil industry, this symbol set was used during the 1990s in about 50% of the world's welding operations. An ISO committee sought to establish a global standard during this decade.

In engineering drawings, each weld is conventionally identified by an arrow which points to the joint to be welded. The arrow is annotated with letters, numbers and symbols which indicate the exact specification of the weld. In complex applications, such as those involving alloys other than mild steel, more information may be called for than can comfortably be indicated using the symbols alone. Annotations are used in these cases.

• Component Elements

In the US, the component elements of the weld specification are:

1. The reference line - the body of the arrow which is the baseline for the specification.
2. The arrow tip which goes at an angle to the reference line, pointing to the joint to be welded.
3. The tail which goes at the other end of the reference line.
4. The basic welding symbol which goes on the reference line to indicate the shape of the weld such as a fillet or plug. The symbol is placed on the arrow side or other side of the line to indicate which side of the joint the weld goes.
5. The dimensions and other numbers such as the length of the weld or number of spot welds go above and below the reference line.
6. Supplementary symbols go at the junction of the reference line and the arrow tip. One such symbol is a circle to indicate an all-around weld, which goes on every side of the joint.
7. Finish symbols go above the reference line to indicate the surface contour or finish of the weld such as flush, convex or concave.
8. Letters indicating the welding process are placed at the tail end, such as AHW for atomic hydrogen welding. Further examples include:

• Abbreviations For Welding Process

If a particular welding process needs to be indicated in addition to the symbols, the following abbreviations are commonly used in North America:

Designation	Welding process
CAW	Carbon-arc welding
DB	Dip brazing
FB	Furnace brazing
FW	Flash welding
GMAW	Gas metal-arc welding
GTAW	Gas tungsten-arc welding
IB	Induction brazing
OAW	Oxy-acetylene welding
OHW	Oxy-hydrogen welding
PGW	Pressure gas welding
RB	Resistance brazing
SAW	Submerged arc welding
TB	Torch brazing
UW	Upset welding

Protractor

A protractor is a square, circular or semicircular tool, typically made of transparent plastic, for measuring angles. Most protractors measure angles in degrees (°). Radian-scale protractors measure angles in radians.

They are used for a variety of mechanical and engineering-related applications, but perhaps the most common use is in geometry lessons in schools.

Some protractors are simple half-discs. More advanced protractors, such as the bevel protractor, have one or two swinging arms, which can be used to help measure the angle.

• Bevel Protractor

A bevel protractor is a graduated circular protractor with a pivoted arm; used for measuring or marking off angles. Sometimes Vernier scales are attached to give more precise readings. It has wide application in architectural and mechanical drawing, although its use is decreasing with the availability of modern drawing software or CAD.

Universal bevel protractors are also used by toolmakers; as they measure angles by mechanical contact they are classed as mechanical protractors.

The bevel protractor is used to establish and test angles to very close tolerances. It reads to 5 minutes or 1/12° and can measure any angle from 0° to 360°.

The bevel protractor consists of a beam, a graduated dial and a blade which is connected to a swivel plate (with Vernier scale) by thumb nut and clamp. When the edges of the beam and blade are parallel, a small mark on the swivel plate coincides with the zero line on the graduated dial. To measure an angle between the beam and the blade of 90° or less, the reading may be obtained direct from the graduation number on the dial indicated by the mark on the swivel plate. To measure an angle of over 90°, subtract the number of degrees as indicated on the dial from 180°, as the dial is graduated from opposite zero marks to 90° each way.

Since the spaces, both on the main scale and the Vernier scale, are numbered both to the right and to the left from zero, any angle can be measured. The readings can be taken either to the right or to the left, according to the direction in which the zero on the main scale is moved.

The above picture illustrates a variety of uses of the bevel protractor.

Reading the Vernier scale:

The bevel protractor Vernier scale may have graduations of 5′ (minutes) or 1/12°. Each space on the Vernier scale is 5′ less than two spaces on the main scale. Twenty four spaces on the Vernier scale equal in extreme length twenty three double degrees. Thus the difference between the space occupied by 2° on a main scale and the space of the Vernier scale is equal to one twenty-fourth of 2°, or 5′.

Read off directly from the main scale the number of whole degrees between 0 on this scale and the 0 of the Vernier scale. Then count, in the same direction, the number of spaces from the zero on the Vernier scale to a line that coincides with a line on the main scale; multiply this number by 5 and the product will be the number of minutes to be added to the whole number of degrees.

For example: Zero on the vernier scale has moved 28 whole degrees to the right of the 0 on the main scale and the 3rd line on the vernier scale coincides with a line upon the main scale as indicated. Multiplying 3 by 5, the product, 15, is the number of minutes to be added to the whole number of degrees, thus indicating a setting of 28 degrees and 15 minutes.

• Gallery
• 

  A half circle protractor marked in degrees (180°).
 
• 

  A 360° protractor marked in degrees.
 
• 

  Another 360° protractor marked in degrees.
 
• 

  A 400^g protractor marked in grads.
 
• 

  A "Cras Navigation Plotter" double-protractor, in foreground.
 
• 

  A half circle protractor marked in degrees (180°).

Technical Drawing Tools

Technical drawing tools are the tools used for technical drawing, including pens and rulers. Drawing tools may be used for measurement and layout of drawings, or to improve the consistency and speed of creation of standard drawing elements. Many of the tools used for manual technical drawing are obsolescent, where computer-aided drawing has become common.

• Drawing Tools

• Pens

Traditional and typical pens used for technical drawing are pencils and technical pens.

Pencils in use are usually mechanical pencils with a standard lead thickness. General line widths are 0.18 mm, 0.25 mm, 0.5 mm and 0.7 mm. Hardness varies usually from HB to 2H. Softer lead gives a better contrast, but harder lead gives more accurate track. Bad contrast of the lead track in general is problematic at photocopying, but new scanning copy techniques have improved the final result. Paper or plastic surfaces do require their own lead types.

"Drawing pens"

Traditional already in the 1600s used ruling pen.   Grafos-stylus.   A disassembled Grafos and nibs of different widths.   Rapidograf styluses of different widths: 0.35, 0.5 and 0.7 mm.   Rapido graph stylus parts. The head is possible to disassemble to even smaller parts

In most cases, the final drawings are drawn with ink, on either plastic or tracing paper. The pen is generally Rapido graph-type technical pen, a marker pen that draws lines of consistent width (so-called steel marker pen). The pen has an ink container which contains a metal tube, inside which is a thin metal needle or wire, the soul. Ink is absorbed between the needle and the tube wall, preventing an excessive amount of ink from being released. The needle has a weight and by waving the pen back and forth the needle is released and the ink can run. Previously, the tank was filled from an ink bottle, newer styluses use ink cartridges.

Each line width has its own stylus. Width of the line is standardized: In Finland, the most commonly used set is 0.13 mm, 0.18 mm, 0.25 mm, 0.35 mm, 0.50 mm and 0.70 mm. There are their own style for tracing paper and plastic, because plastic requires a harder pen tip. To function well they require regular maintenance, the finest marker pens in particular

• Drawing Board

The drawing board is an essential tool. Paper will be attached and kept straight and still, so that the drawing can be done with accuracy. Generally, different kind of assistance rulers are used in drawing. The drawing board is usually mounted to a floor pedestal in which the board turns to a different position, and also its height can be adjustable. Smaller drawing boards are produced for table-top use. In the 18th and 19th centuries, drawing paper was dampened and then its edges glued to the drawing board. After drying the paper would be flat and smooth. The completed drawing was cut free. Paper could also be secured to the drawing board with pins. More recent practice is to use self-adhesive tape to secure paper to the board. Some drawing boards are magnetized, allowing paper to be held down by long steel strips. Boards used for overlay drafting or animation may include registration pins or peg bars to ensure alignment of multiple layers of drawing media.

• Drafting Machine

A drafting machine is a device which is mounted to the drawing board. It has rulers whose angles can be precisely adjusted with a controlling mechanism. There are two main types of apparatus: an arm-type parallelogram apparatus based on a hinged arm; and a track-type apparatus which moves on a rail mounted to the top of the drawing board. The accuracy of the arm type apparatus is better in the middle of the board, decreasing towards the edges, whereas a track machine has a constant accuracy over the whole board. The drawing head of a track-type drafting machine slides on bearings in a vertical rail, which in turn is moved along a horizontal, top-mounted rail. Both apparatus types have an adjustable drawing-head with rules attached to a protractor scale so that the angle of the rules may be adjusted.

A drafting machine allows easy drawing of parallel lines over the paper. The adjustable angle between the rulers allows the lines to be drawn in varying accurate angles. Rulers may also be used as a support for separate special rulers and letter templates. The rules are replaceable and they can be for example scale-rules.

Drawing apparatus has evolved from a drawing board mounted parallel ruler and a pantograph, which is a device used for copying objects in an adjustable ratio of sizes.

• Rulers

Rulers used in technical drawing are usually made of polystyrene. Rulers come in two types according to the design of their edge. Straight edge can be used with lead and felt pens, whereas when technical pen is used the edge must be grooved to prevent the spread of the ink.

Architect's scale is a scaled, three-edged ruler which has six different scales marked to its sides. A typical combination for buildings details is 1:20, 1:50, 1:100, 1:25, 1:75 and 1:125. There are their own rulers for zoning work as well as for inch units. Today scale rulers are made of plastic, formerly of hardwood. A pocket-sized version is also available, with scales printed on flexible plastic stripes

Dimensions Of Letters

• The Nominal Size of lettering is defined by the height (h) of the outline contour of the upper-case (capital).
• Central Line is the imaginary line in the middle of each line or line element which is a constitutive part of a graphic character set.
• If we consider d as the width of the line element and h as the height of the line element, then the two standard ratios for d/h are: 1/14 and 1/10, which are feasible because they result in a minimum number of line thicknesses.
• Location of Central Lines- The nominal size (h) and the spacing between characters (a) shall be taken as the basis for defining the central line.
• Range of Nominal Sizes -The range of nominal sizes are 2.5 mm ;3.5mm ; 5 mm; 7 mm; 10 mm; 14 mm; 20 mm;
• The multiple of 1.414(square root of 2) is the range of heights for lettering is derived from the standardized progression of dimensions for paper sizes.
• Lettering Angle-The lettering may be vertical (upright) or inclined (sloped) to the right at 75° from the horizontal.
• The spacing between two characters may be reduced by half, if this gives a better visual effect.
• various letters are divided into no. of parts so that dimensions will be accurate.
  
• The size of letter is described by its height. According to the height of letters, they are classified as :

Lettering A

Characteristic	Parameter	Ratio	Dimensions(mm)
Lettering Height (Height of capitals)	h	(14/14)h	2.5	3.5	5	7	10	14	20
Height of lower case letters (without stem or tail)	c	(10/14)h	-	2.5	3.5	5	7	10	14
Spacing between characters	a	(2/14)h	0.35	0.5	0.7	1	1.4	2	2.8
Minimum spacing of base characters	b	(20/14)h	3.5	5	7	10	14	20	28
Minimum spacing between words	e	(6/14)h	1.05	1.5	2.1	3	4.2	6	8.4
Thickness of lines	d	(1/14)h	0.18	0.25	0.35	0.5	0.7	1	1.4

Lettering B

Characteristic	Parameter	Ratio	Dimensions(mm)
Lettering Height (Height of capitals)	h	(10/10)h	2.5	3.5	5	7	10	14	20
Height of lower case letters (without stem or tail)	c	(7/10)h	-	2.5	3.5	5	7	10	14
Spacing between characters	a	(2/10)h	0.5	0.7	1	1.4	2	2.8	4
Minimum spacing of base characters	b	(14/10)h	3.5	5	7	10	14	20	28
Minimum spacing between words	e	(6/10)h	1.5	2.1	3	4.2	6	8.4	12
Thickness of lines	d	(1/10)h	0.25	0.35	0.5	0.7	1	1.4	2

Mechanical Lettering

In topic we discussed pens that are used primarily for freehand lettering. At times, however, you will be tasked with preparing drawings, charts, maps, or signs that require the use of mechanical lettering. When we refer to mechanical lettering, we mean standard uniform characters that are executed with a special pen held in a scriber and guided by a template. Mechanical lettering does not normally require the use of lettering guidelines. You will use mechanical lettering principally for title blocks and notes on drawings, marginal data for special maps, briefing charts, display charts, graphs, titles on photographs, signs, and any other time that clear, legible, standardized lettering is required. It should be noted that freehand lettering is the required lettering on most of your drawings;mechanical lettering should be confined to special uses similar to those described above. The availability of mechanical lettering devices should not deter you from the daily practice required to execute freehand lettering. With continuous practice you will become proficient with both mechanical and freehand lettering.

One of the most popular types of mechanical lettering sets is the LEROY lettering set. A

standard Leroy lettering set consists of a set of templates, a scriber, and a set of pens.

Templates

Templates are made of laminated plastic with the characters engraved in the face so that the lines serve as guide grooves for the scribe. The height of the characters, in thousandths of an inch, is given by a number on the upper right-hand side of the template. For example, 3240-500CL indicates a No. 500 template. The entire number and letter designation identifies the template in the manufacturer’s catalog. The range of character heights offered by a standard set of templates is from 80 (0.08 in. or 5/64 in.) to 500 (0.5 in. or 1/2 in.). The scale at the bottom of each template has the zero in the center and is arranged for proper spacing in relation to character heights. The distance between each scale division represents the center-to-center distance of normal-width letters.

Pens

A standard set of pens for producing various line weights consists of 11 sizes ranging from 000, the finest, to 8. Each pen is composed of two parts: the ink reservoir and the cleaning pin. The reservoir is a series of connected tubes of decreasing diameters, the smallest establishing line thickness. The cleaning pin acts as a valve, protruding beyond the edge of the bottom tube when the pen is not touching the drawing surface. In this position, no ink flows. When the pen is resting on a drawing surface, the cleaning pin is pushed up, allowing a flow of ink. Action of the pin in the tube minimizes ink clogging.

NOTE: As stated in chapter 2, some reservoir pens are made so the point section will fit in a Leroy scriber. They have become popular with the SEABEEs (and widely used over the standard pens contained in the Leroy lettering set), especially for long hours of uninterrupted lettering. A SCRIBER holds the pen in alignment and controls its motion as the tracing pin is guided through the character grooves of the template. Two types of scribes are available: adjustable and

fixed. An adjustable scriber produces letters with any slant from vertical to 22 1/2 degrees forward from a single template; a fixed scriber produces only vertical letters. Both scribers consist of a tracing pin, pen socket, socket screw, and a tail pin. Figure 3-59 shows a fixed scriber. The tracing pin on most Leroy scribers is reversible, One point is used with fine groove templates (Nos. 060, 080, and 100), and the other point is for wider groove templates (No. 120 to No. 500).

Orthographic Projection

The orthographic projection shows the object as it looks from the front, right, left, top, bottom, or back, and are typically positioned relative to each other according to the rules of either first-angle or third-angle projection. The origin and vector direction of the projectors (also called projection lines) differs, as explained below.

• In first-angle projection, the projectors originate as if radiated from a viewer's eyeballs and shoot through the 3D object to project a 2D image onto the plane behind it. The 3D object is projected into 2D "paper" space as if you were looking at a radiography of the object: the top view is under the front view, the right view is at the left of the front view. First-angle projection is the ISO standard and is primarily used in Europe.

• In third-angle projection, the projectors originate as if radiated from the 3D object itself and shoot away from the 3D object to project a 2D image onto the plane in front of it. The views of the 3D object are like the panels of a box that envelopes the object, and the panels pivot as they open up flat into the plane of the drawing. Thus the left view is placed on the left and the top view on the top; and the features closest to the front of the 3D object will appear closest to the front view in the drawing. Third-angle projection is primarily used in the United States and Canada, where it is the default projection system according to British Standard BS 8888 and ASME standard ASME Y14.3M.

Until the late 19th century, first-angle projection was the norm in North America as well as Europe but circa the 1890s, the meme of third-angle projection spread throughout the North American engineering and manufacturing communities to the point of becoming a widely followed convention and it was an ASA standard by the 1950s. Circa World War I, British practice was frequently mixing the use of both projection methods.

As shown above, the determination of what surface constitutes the front, back, top, and bottom varies depending on the projection method used.

Not all views are necessarily used. Generally only as many views are used as are necessary to convey all needed information clearly and economically. The front, top, and right-side views are commonly considered the core group of views included by default, but any combination of views may be used depending on the needs of the particular design. In addition to the 6 principal views (front, back, top, bottom, right side, left side), any auxiliary views or sections may be included as serve the purposes of part definition and its communication. View lines or section lines (lines with arrows marked "A-A", "B-B", etc.) define the direction and location of viewing or sectioning. Sometimes a note tells the reader in which zone(s) of the drawing to find the view or section.

Orthographic Projection

Orthographic projection (or orthogonal projection) is a means of representing a three-dimensional object in two dimensions. It is a form of parallel projection, where all the projection lines are orthogonal to the projection plane, resulting in every plane of the scene appearing in affine transformation on the viewing surface. It is further divided into multi-view orthographic projections and axonometric projections. A lens providing an orthographic projection is known as an (object-space) telecentric lens.

The term orthographic is also sometimes reserved specifically for depictions of objects where the axis or plane of the object is also parallel with the projection plane, as in multi-view orthographic projections.

Multi-view Orthographic Projection

With multi-view orthographic projections, up to six pictures of an object are produced, with each projection plane parallel to one of the coordinate axes of the object. The views are positioned relative to each other according to either of two schemes: first-angle or third-angle projection. In each, the appearances of views may be thought of as being projected onto planes that form a 6-sided box around the object. Although six different sides can be drawn, usually three views of a drawing give enough information to make a 3D object. These views are known as front view, top view and end view.

Sizes Of Drawings

Paper Size

Sizes of drawings typically comply with either of two different standards, ISO (World Standard) or ANSI/ASME Y14 (American), according to the following tables:

            ISO A Drawing Sizes(mm)

A4	210 X 297
A3	297 X 420
A2	420 X 594
A1	594 X 841
A0	841 X 1189

            ANSI/ASME Drawing Sizes (inches)

A	8.5" X 11"
B	11" X 17"
C	17" X 22"
D	22" X 34"
E	34" X 44"

            Other U.S. Drawing Sizes

D1	24" X 36"
E1	30" X 42"
H	larger still [intra company standards]
I	larger still [intra company standards]
J	larger still [intra company standards]

 

The metric drawing sizes correspond to international paper sizes. These developed further refinements in the second half of the twentieth century, when photocopying became cheap. Engineering drawings could be readily doubled (or halved) in size and put on the next larger (or, respectively, smaller) size of paper with no waste of space. And the metric technical pens were chosen in sizes so that one could add detail or drafting changes with a pen width changing by approximately a factor of the square root of 2. A full set of pens would have the following nib sizes: 0.13, 0.18, 0.25, 0.35, 0.5, 0.7, 1.0, 1.5, and 2.0 mm. However, the International Organization for Standardization (ISO) called for four pen widths and set a color code for each: 0.25 (white), 0.35 (yellow), 0.5 (brown), 0.7 (blue); these nibs produced lines that related to various text character heights and the ISO paper sizes.

All ISO paper sizes have the same aspect ratio, one to the square root of 2, meaning that a document designed for any given size can be enlarged or reduced to any other size and will fit perfectly. Given this ease of changing sizes, it is of course common to copy or print a given document on different sizes of paper, especially within a series, e.g. a drawing on A3 may be enlarged to A2 or reduced to A4.

The U.S. customary "A-size" corresponds to "letter" size, and "B-size" corresponds to "ledger" or "tabloid" size. There were also once British paper sizes, which went by names rather than alphanumeric designations.

American Society of Mechanical Engineers (ASME) Y14.2, Y14.3, and Y14.5 are commonly referenced standards in the U.S.