A heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable. It involves heating a material above its recrystallization temperature, maintaining a suitable temperature for a suitable amount of time, and then cooling. Mill-Max brass pins and Receptacles are often annealed to make them easier to crimp, rivet (swage) or bend.
Barb Example

Sometimes referred to as a fish hook, a barb is a common press-fit feature provided on many pins, receptacles, and spring pins used for retention purposes in insulators or plastic housings. Barbs do not offer any anti rotation properties. For these applications engineers should consider a knurl retention feature.

Blind Mate

Mating of one or more components where visibility is obstructed or limited.


Refers to the central section of a pin, receptacle, or spring pin. Typically machined out of a brass alloy material.

Bottom Entry Receptacle

A type of receptacle that requires the mating pin/lead to be inserted from the exit to the entry. View Examples.


A slight deformation of the receptacle shell that might occur after a contact clip is inserted during the assembly process. Typically results in a .001”-.003” increase in the outer diameter of the receptacle shell located near the contact entrance.

A primary component of a spring-loaded pin that holds the assembly together. It is typically the largest diameter or base of the product.

An assembly consisting of an insulator with male dummy pins onto which receptacles are loaded. This assembly is employed as a fixture during the soldering operation and is then removed leaving a PC board populated with individual receptacles. Carriers that load male pins are also available for special applications as custom/made to order solutions. View Examples.

Clip (Contact)

Multi-finger spring insert of a receptacle which completes the electrical path between a male pin and a female receptacle. Also referred to as a clip. Typically stamped and formed from Beryllium Copper and/or Beryllium Nickel.

Closed Entry/Bottom

Refers to female contacts where the front rim prevents the insertion of an oversize pin that would otherwise damage the contact. View Examples.


A contact clip's ability to accept multiple insertions and extractions of a wide range of pin shapes and sizes while retaining its original configuration.

Compliant Press Fit

Method of mounting an interconnect component to a PC board where a drilled and slotted receptacle or pin feature is pressed into a plated through hole without damaging the hole.

Constant Usage Temperature (CUT)

Constant Usage Temperature is a measure of the maximum temperature that a material may be exposed to for long periods of time, 1000-1500 hrs., before degradation of its electrical and mechanical properties occurs.

Contact (and Contact Clip)

Multi-finger spring insert of a receptacle which completes the electrical path between a male pin and a female receptacle. Also referred to as a clip. Typically stamped and formed from Beryllium Copper and/or Beryllium Nickel.

Contact Rating

Current carrying capability of a contact measured in amperes with respect to temperature rise above ambient.

Contact Resistance

The electrical resistance at the point of connection determined by the contact geometry, area of contact, plating and normal force.


Refers to the measurement of multiple points and their distance from a respective plane. This is particularly useful for surface mount parts to determine the maximum amount of difference in the height of the surfaces that need to be soldered.


A deformation, typically located on the body/barrel of a pin, receptacle, or spring pin. The deformation is created from a Crimp Tool. This deformation allows for solderless wire termination to the product.For more information view the following video, How to Crimp Contacts, By Daniels Manufacturing Corporation.

Device under Test (DUT)

Device or part being tested

Dual Entry Receptacle
Receptacle containing contact clips at both openings or containing an individual contact clip that is suitable for either top or bottom entry.

A product’s anticipated life expectancy. Actual life is derived from the application along with the application conditions, temperature/cleanliness of the environment, and mating pin specifications.

Early Engagement

A contact clip designed to form a strong connection with a mating lead/pin without needing to pass its fingers/tines. View Examples

Electro-Vibratory Plating
An electroplating system where the parts are processed in a vibrating basket which ensures uniform plating thickness and avoids damage to delicate parts.
Electroless Plating
Plating activation with the use of acid or solutions rather than means of an electric current to form a deposit.

To relate to or involve an electrically operated mechanical device


One of the most important processes in the manufacturing of electronic parts and components is electroplating, which involves the application of a metal coating via electrodeposition. This is done for a number of reasons such as improving corrosion resistance, enhancing electrical conductivity, increasing the solderability of the substrate and protecting against wear.

Electrostatic Discharge (ESD)

The momentary electric current that flows between two objects that may cause damage to electronic equipment.

End Stackable

The ability for connectors to be mounted end to end while maintaining grid or spacing.


Woven glass cloth epoxy laminate. Classified as a thermoset, the woven fibers of these materials enable them to withstand high temperatures without being damaged. Cut from large sheets of material, the insulator is then machined on a high speed drill/router, the same way as printed circuit boards are fabricated.

Extraction Force

The force required to remove a lead from a contact. Also known as withdrawal force.

Fibre Plug / OFP® Solder Barrier
An organic paper plug used to create a solder barrier in open bottom receptacles. Once soldering is complete, the mating lead knocks the plug out.

An external or internal rib, or rim (lip), typically used for strength/support purpose.

Flash (Plating)

A very thin plating, usually less than 10 micro inches, only enough metal to uniformly cover the surface of the base metal.


Sometimes used in place of coplanarity, flatness refers to the amount of variation of a plane or surface.

Floating Contact

In surface mount sockets, a receptacle designed to move up and down freely in an insulator to compensate for unevenly dispensed solder paste.

Free Machining Alloy

An alloy which is easy to machine, e.g. brass alloy 360.


A form of corrosion caused by vibration.

Gas Tight Connection

An electrical connection of sufficient pressure to prevent the intrusion of a corrosive atmosphere into the contact area.

Gold Plating

Gold is commonly used in the plating of many different electronic components. Gold offers low and stable contact resistance and superior protection against corrosion. 

Nickel is often used to provide an underlying coating when using gold to plate electronics. Nickel acts as an extra corrosion inhibitor by preventing rust from penetrating pores in the surface. Nickel also prevents the diffusion of other metals into the gold surface such as zinc or copper. What's more, nickel can increase the durability of the gold-plated surface.

Mill-Max offers most of its products in standard platings ranging from 5 to 30 µin of gold over nickel. Since plating operations are conducted in house other thicknesses are available on request. 

Heat Deflection Temperature (HDT)

An industry recognized test for comparing the short term effects of high temperature on plastics.

Heat Treating

The process of using specific heating and cooling cycles to alter the mechanical properties of an alloy. Generally, heat treating can harden or soften a metal depending on the material, the parameters used and the desired physical property.

Example of a Hex Press-Fit

A hexagonal cross section machined around the body of a receptacle or pin providing a retention feature for press-fitting in a PC board with a Plated Through-Hole (PTH). It can also prevent rotation of the pin, while still maintaining a Gas Tight Connection. View Examples.


High Speed Turning

See Precision-Machined.

Injection Molding

A method of molding plastics by first heating granular plastic to its molten state and injecting it into the mold cavity where the plastic solidifies and is then ejected from the cavity.

Insertion Force

The force required to insert a male lead into a female socket.


Means of connection that supplies an electrical connection between the cells.

IP Rating
Measurement of how well a piece of equipment or device can resist penetration of water, chemicals, dust and other fluids or debris. Sometimes known as the water resilience or level of ingress protection a product has.
Example of a Knurl

A vertical serration machined around the diameter of a receptacle or pin providing a retention feature for press-fitting in a PC board or insulator while also preventing rotation of the pin. View Examples.



Typically, gold plated, round or flat surface, commonly used for mating purposes also known as a target.

LCP (Liquid Crystal Polymer)

Classified as a thermoplastic, LCP is a hard, rigid material which exhibits outstanding strength at high temperatures and exceptional strength and toughness in its thin walls. Applications: LCP is used as an insulator material for tight grid (.050", 2mm) connectors and extremely high temperature requirements.

Light Insertion Force

Manufacturing process whereby a rapidly turning solid metal rod is cut to precise tolerances. Also known as Screw-Machined or Precision Machined.

Mated Height
The assembled height of a male and female interconnect once engaged/mated.
Mating Pin

The pin used to interconnect two electronic devices by inserting it into the contact. Critical features are diameter, length, and shape (but not limited to.)

Max Stroke

The maximum distance a plunger on a spring-loaded pin can be compressed.


Considered the optimal stroke distance for all spring-loaded products. The Mid-Stroke will be (~) approximately half of the Max Stroke.


Having incorrect alignment between mating components, features or products within a system.

Mounting Hole Size

Size call out for the mounting holes.

Nail Head Pins
A male pin in the shape of a nail.
Nylon 46

Classified as a thermoplastic, Nylon 46 offers superior heat resistance, good electrical properties and excellent toughness in its thin walls, which are desirable characteristics for connector insulators. Its superior strength in thin walls enables the press-fitting of pins in close proximity to each other without cracking or warping the material, making it ideal for molding 1mm, 2mm and .050" grid insulators. Nylon 46 is suitable for high temperature applications including vapor phase, infra-red reflow and wave soldering operations.

OFP® Solder Barrier/Fibre Plug

An organic paper plug used to create a solder barrier in Open Bottom receptacles. Once soldering is complete, the mating lead knocks the plug out.

Open Bottom

Receptacle shell has a full length internal coaxial hole. The part is hollow or straw-like. View Examples.

Operating Temperature
The operating temperature is the temperature at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the maximum operating temperature (or peak operating temperature). Outside this range of safe operating temperatures the device may fail.

Sometimes occurs when a spring is compressed to the point where it sets and holds a position, essentially deforming and stretching the spring to an undesired position.

Passive Device or Component

An electronic connector that consumes electrical energy, but does not produce electrical energy. Passive devices are not susceptible to significant ESD damage.

A printed circuit board (PCB) mechanically supports and electrically connects electronic components or electrical components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Components are generally soldered onto the PCB to both electrically connect and mechanically fasten them to it.
PCB Connectors

PCB Connectors can be referred to as PCB Interconnects or Rectangular Connectors. Specific terms are also used for the two sides of the connection. Male PCB Connectors are often referred to as Pin Headers, as they are simply rows of pins. Female PCB Connectors can be called Sockets, Receptacles, or Socket Headers.

PCT (Polycyclohexane Terephthalate)

Thermoplastic polyester is rated for higher temperatures. PCT is a standard material on DIP and SIP insulators for higher temperature operations. All PGA and surface mount products are molded from PCT and are suitable for infra-red, vapor phase and wave soldering.

Pick & Place Cap/Clip
A removable component typically molded out of plastic that assists with keeping the parts centered in the carrier tape pocket while also presenting a larger surface for easier vacuum pick up.
Plated Through-Hole (PTH)

A hole in a printed circuit board which has metallic walls connected to conductors on the surface or inside the board, in which the component lead is inserted and soldered.


A process in which metals (e.g. gold, tin-lead, nickel, silver) are electrically deposited onto a base metal in very thin and precise thicknesses.


An active driving component, typically driven by a spring.


Manufacturing process whereby a rapidly turning solid metal rod is cut to precise tolerances. Also known as Screw-Machined or just simply Machined.


To use a designed (Barb, Hex, Square, or Knurl) feature to secure a pin, receptacle, or spring-loaded pin into a board, housing, or Plated Through-Hole (PTH).

Sometimes referred to as PCB sockets, micro-plugs or connector jacks, machined pin receptacles are known for their reliability and versatility. The pin receptacle is a 2 piece female contact consisting of an outer shell and inner spring contact (clip) designed for multiple mating/unmating cycles with a male pin or component lead. Used discretely in a PC Board or in plastic as connector arrays, receptacles make devices and modules pluggable for repair and replacement.

Manufacturing process whereby a rapidly turning solid metal rod is cut to precise tolerances. Also known as Precision-Machined or just simply Machined.

Secondary Machining

A process in which holes, slots, flats, squares or other special features may be machined onto a pin or receptacle after the basic shape of the part has been turned on a high speed lathe.

A precision screw machined housing for the internal contact clip.

An external or internal rib, or rim (lip), typically used for strength/support purpose.

Shrink DIP Package

An IC which has a pin spacing of.070" on centers.

Side Load

A horizontal or lateral force that is applied to a part or component in an application.


The removal of a thin amount of plating when pins or contacts are press fit. For example, soft platings may yield some amount of skiving upon press fitting into an insulator or board. Skiving may also appear under a contact clip pressed into a receptacle shell.

Solder Tail

For Through-Hole requirements, this tail feature serves as a stable anchor for either soldering or mounting.

Spring Force

The amount of force required to compress a plunger to a specified distance.

Spring Force Constant

(Conducted on a MM # 0900-X Spring Pin Connector)

k = Force (60) - Preload (25)/Travel (.0275) = 1272.73 g/in.

Preload = 25 g
Force = 60 g
Travel = .0275"

Spring Rate

The spring rate of a spring will be determined by spring material, diameter of the material, and number of coils per the spring length.

Standoff / Mounting (Alignment) Peg

A protrusion at the bottom of the connector used to raise it off the PC board to aid in solder fillet formation, board inspection, flux removal and cleaning.

Swage Mount

A type of mounting commonly used with solder terminals and printed circuit pins where one end of the terminal is flared out (riveted) securing it to the PCB.


Typically, gold plated, round or flat surface, commonly used for mating purposes also known as a land or pad.

Thermal Coefficient of Expansion (TCE)

Expansion of material caused by an increase in temperature.


Type of plastic which is molded under heat and pressure and can be remelted & reused many times.


Type of plastic which is heat cured into a permanent shape, and due to chemical reaction, cannot be remelted.

Top Plate

Final surface plating over base metal and underplating.


Plating between the base metal and the top plating.

Wire Crimp

Please see Wire Termination

Wire Termination

Typically involves wire insertion, crimping or soldering into the vacant coaxial hole located on the pin/receptacle.

Withdrawal Force

The force required to remove a lead from a contact. Also known as extraction force.

Wrapost (Terminal or Receptacle)

The length of square cross section of certain pins and receptacles which is used for making electrical connections via wire wrapping. Wire wrapping is a process in which wire is wrapped around the post to form a gas-tight connection without soldering.

Zero Insertion Force
Zinc Migration

For a brass part plated with tin or gold, the migration of zinc from brass to the surface of the plating. This becomes zinc oxide and renders the part unsolderable. Zinc migration is prevented by using a copper or nickel underplate as a barrier.

Last Updated: 12/11/2018 08:33 AM