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tech
jeepfan.com
Guide to a Jeeper's Garage
Hand Tools
Punches
Like most tools
a punch can come in many sizes and varieties. In this
article we cover the most common types of punches that may
be used in a typical Jeeper's garage. As with all
tools use proper safety equipment and procedures when in
use.
Center Punch
A center punch
is typically used as an aid to drilling operations; a drill,
when brought into contact with a flat surface, will have a
tendency to wander on the surface until it gains sufficient
purchase to start cutting a hole. A center punch forms a
small dimple in which the tip of the drill (if it is small
enough) will fit. 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. A
center punch usually has a tip, that when viewed on a
profile, has sides at a 90 degree angle to one another.
Prick Punch
 A
prick punch, while easily confused with the similar looking
center punch, serves an entirely different purpose. A prick
punch is primarily used for the purposes of layout. By
design it produces a smaller indentation than a center
punch, which acts as a useful datum point in layout
operations. When layout is complete, the indentation made
with a prick punch can be enlarged with a center punch to
allow for drilling. A prick punch usually has a tip, that
when viewed on a profile, has sides at a 30-60 degree angle
to one another.
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Transfer Punch
 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. |
Pin Punch
 The
purpose served by pin punches is somewhat different to the
center or prick punches. A pin punch is used as a driving
tool, typically, as the name implies, to drive pins that are
used to affix a fixture to a rotating shaft. Pin punches are
typically characterized by a hexagonal body, with a long,
flat ended cylindrical section.
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, 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.
Recommendation
A set of center
punches, drifts, and pin punches. Usually best bought
in a set from a quality tool reseller. A set of
transfer punches in common hole sizes would be an add on.
Popular Punch
Manufacturers and Resellers
Craftsman
SnapOn
Matco
Husky
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