A brief history…

“Man is a tool-using animal. Weak in himself and of small stature, he stands on a basis of some half square foot, has to straddle out his legs lest the very winds supplant him. Nevertheless, he can use tools, devise tools; with these the granite mountain melts into light dust before him; seas are his smooth highway, wind and fire his unwearying steeds. Nowhere do you find him without tools. Without tools he is nothing, with tools he is all.”
Thomas Caryle (1795-1881)

Since 1880 for over 140 years of precision toolmaking, the L. S. Starrett Company has encouraged higher standards of workmanship by helping vocational students, apprentices, mechanics and tool makers understand tools and how to use them effectively. There are no tools throughout history more suited to Thomas Caryle’s quote than the steel punch and no tool we take as much pride in making.
The basic definition of 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. At Starrett we would also include: Punches are well proportioned, hardened, properly tempered, nicely finished, and have a knurled finger grip. Punches are used to drive objects, such as nails, or to form an impression of the tip on a work piece and usually struck with a ball-peen hammer. Various decorative punches may also be used to create a pattern or even form an image. Various Punch Styles include; Drive Pin, Center, Automatic Center, Prick, Transfer, Drift, Roll Pin, Decorative, Letter, and Nail.

Types of Punches

Drive Pin Punches
A Drive Pin Punch is a tool used to drive pins for affixing a fixture to a rotating shaft. 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. Accurate sizing of the punch is critical as well the tempering of punch. Drive Punches come in two overall lengths standard the 4 inch with varying drive lengths, the smaller the punch diameter the shorter the allowable drive length the smallest 1/16th diameter being ¾ inch long while the largest being 5/16 in diameter having a 1 inch long area. And extended drive punches Starrett 248 and 248B that are 8 inches long with their 3 ½ long drive lengths. These punches as the name implies are used on pin drive lengths longer than the shorter 565 can push. Designed to withstand hard use, they provide a most satisfactory punch for machine shop and motor service work.

Pin Punches are also made out of brass which is ideal for softer materials. Solid brass prevents damaging delicate work. One technique is to use the steel style first to loosen the pin and when it begins to move you then switch to the brass style so as not to damage the original surface should the pin suddenly loosen and pull free.

Center Punches
A center punch is used to mark the centre of a point. It is usually used to mark the centre of a hole when drilling holes. A drill has the tendency to "wander" if it does not start in a recess. A centre punch forms a large enough dimple to "guide" the tip of the drill. The Tip of Centre Punch has an angle of 90 Degrees. A quality Center Punch is ground at the proper angle and accurately centered at the tip When drilling larger holes, and the web of the drill is wider than the indentation produced by a centre punch, the drilling of a pilot hole is usually needed.
The punches have either round knurled shanks for ease of grip or in square shank style so the punch does not roll of the work bench. These punches are heat treated so as to have hardened tips while the opposite end is drawn back softer so as not to shatter when struck by a hammer.

Prick Punches
A prick punch also know as a dot 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 allowing more precise positioning than can be achieved using the more blunt Center punch. The mark can then be enlarged with a center punch for drilling. The Tip of Prick Punch is less than 60 Degrees.

 
Transfer Punches
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.

Drift Pin Punches
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 Punches
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 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. Roll pin punches are designed with a small projection in the center of the pin tip to support the circumference of the roll pin.

Decorative Punches
Punches with a decorative motif have been used to create patterns or images on metals and various other materials, notably leather.

Letter Punches
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.

Nail Punches
Similar to a Pin Punch, a nail punch also called a nail set, is used to drive the head of a nail flush with or below a surface. Quality Nail Sets include an accurate cupped punch surface to engage the nail head. When a finish nail is driven into the wood a carpenter stops hammering, leaving its head exposed. This reduces the chance of striking the wood and leaving a “blossom” mark from the hammers face. To “set” a finish nail below the wood surface select the proper punch from the set so that its tip properly fits the nails head, then drive the nail, setting its head below the woods surface allowing finishing.

Safety Precautions

The most important precaution to take, aside from the common one of always wearing eye protection is to use the correct size hammer the use of too large a hammer could result in the bending of the smaller diameter tools. Light taps to begin the release are expected. And if unsuccessful other means may be required like soaking the area with a penetrant to loosen any rust that might be present.

Why use an Automatic center punch?
An automatic center punch operates without the need for a hammer. An internal mechanism automatically strikes a blow when downward pressure is applied. Spring tension, which regulates the blow, is constant so marks made by the point are uniform in depth and size for each setting.

Most punches are made of steel and are a spring loaded with a knurled cap that also is spring loaded to adjust the striking pressure. The tools have an easily replaceable tip should it ever be damaged. Starrett also offers the 818 style with an aluminum body designed to resist the rusting that could occur on the standard catalog 18 tools.

 
The catalog 18 punch group is available in three varieties, the 18AA being the smallest in 4 inches long with a striking pressure of 4-6 pounds and being 7/16 inch in diameter. The 18A is next being 5 inches long with the 9/16 diameter and having a strike of 15-20 pounds the largest in the series is the 18C with a body diameter of 11/16 and length of 5 ¼ and striking pressure of 40-65 pounds.

 
Position the punch in place and using the palm of your hand press down on the tool. The punch tip will retract into the body and at a set point will “trip” causing the point to fire and produce the dimple. Relaxing your palm will allow the tool to reset and be ready to produce another point. To adjust the striking pressure turn the knurled cap counter clockwise to decrease the strike.

Starrett also offers the Catalog 819 auto punch, this aluminum bodied tool is constructed in the same manner as the tools listed above but it has one distinction in that is designed to be used by the carpenter to set the hinges on a door. It specially equipped collar at .183 is designed to fit in the countersunk holes in the doors hinges. This cone automatically aligns the center punch so it strikes in the center of the hinge hole assuring the correct alignment and eliminating the doors chance of being hinge bound.

 
My punch is not consistent and sometimes refusing to fire!
If the 18 has an issue with activating its mechanism, there is a simple thing you can try: Unscrew and remove the cone style tip and remove the trip pin and its spring. Take the spring off the pin (making note it is tapered, the smaller diameter slid over the pin). Stretch this spring out to about half its length and replace, making sure it is on the pin correctly. Replace the cone and try the tool. If this does not correct the issue it should be returned to Starrett repair department.

Hammers

Information on punches is not complete with out talking about the companion piece the hammer.

Brief history

The first hammer is believed to be used about 3 million years ago it was possibly a simple rock, shaped to fit in the hand and used to pound flesh for removing the skin before consuming.

No one knows for sure when the design was upgraded to include the attachment of a handle, cave drawings dated to about 30 thousand years ago show this improvement, most likely the design was upgraded as a weapon. Much later we find the Norse word Hamarr which translates to Stone Crag or “tool with stone head.

Next improvements were made during the bronze age and that gave way to iron around 2000 B.C. this change allowed the hammer to be offered in more styles again driven by the need for advanced weapons (the hatchet) but also tools for blacksmiths and carpenters.

Today the most common hammers are the claw style used by carpenters and they are available in many styles designed to allow the extraction of nails. Second most popular are the ball pean style and they come in many weights.

There is even a federal specification (GGG- P-831C) for the recommended size/weight for use with drive pin style punches: 1/16-5/16 inch punches recommended use is a tool no larger than 8 ounces. 3/8-1/2 inch are 16 ounce and 5/8 can use 24 ounce.

Catalog 815 Hammer:
Along with the punches listed above Starrett offers a unique tool, it is our 815 Hammer. This small light weight forged steel hammer has both a flat and ball end along with a  built in magnifying glass (ten Power) that eliminates the usual fumbling and looking away involved when a separate magnifying glass and hammer are used. The high power of the glass allows you to position the tip of the 816 prick punch on the scribed line, turn the hammer and strike without taking your eyes off the work.