This glossary explains what the following terms mean to me (the author) within the context of this document.


3/8th NPT Ports    See the definition of a port.  3/8th NPT means the female threads into the valve are 3/8” National Pipe Threads.


3-Way 2-Position Valve 


A valve with three ports (where hoses are usually connected) that has an internal spool that can be moved to (internally) re-configure how air passes through the valve.  

The Roller Valve and Air Gate are 3-Way 2-Position valves.


NORMALLY CLOSED.   Pressurized air flows from Port 1 to Port 2 when the button (or lever) is pushed in.  Exhaust air flows from Port 2 to Port 3 when button (or lever)  is released.  

The Roller Valve is plumbed as a normally closed valve.

NORMALLY OPEN.  Pressurized air flows from Port 3 to Port 2 when the button (or lever) is not pushed.  Exhaust air flows from Port 2 to Port 1 when the button (or lever) is pressed.

The Air Gate is plumbed as a normally open valve.

DIVERTER.  Pressurized air flows from Port 2 to Port 1 when the button (or lever) is pushed.  Pressurized air flows from Port 2 to Port 3 when the button (or lever) is released. This hookup does not provide for exhaust release.


4-Way Valve   A short name for the 5-Port 4-Way 2-Position Directional Flow Control Valve in the Cricket Air Circuit.


5 Port, 4-Way Directional Flow Control Valve   A valve that uses 5 Ports to implement the function of a 4-Way Valve.  Flow Control means the valve can re-configure its internal passageways, using an internal spool.


6th Port   The 4-Way Valve description references “5 ports”.  Those ports are used to manage the air flow to and from the Cylinder.

There is a 6th port called the Spool Control Port that is used (with pressurized air) to move the spool.


Air-Assist Spool Control Port   This is the 6th port on the directional control valve.

When pressurized air is introduced to this port, the spool is moved (from its normal position) to its working position, changing the direction of air flow through the 4-Way Valve. 


Air Circuit   The Air Circuit consists of all the components (and plumbing) necessary to manage the air flow used to cycle the Ram.


Air Circuit Components  The list of parts needed to implement an Air Circuit.


Air Gate The Air Gate is a 3-Way 2-Position air valve implemented as on-off switch, controlling the pressurized air that is to be made available to the Roller Valve.


Air Input Side   This is where the shop air is introduced to the Cricket Air Circuit (at Butterfly Valve 1).


Alignment   Being in alignment refers to both the Ram guide system and the Cylinder being mounted so there is no sideways stress on the rod when the Ram is cycling.  

The Cricket utilizes an interface unit, called an Alignment Coupler, that allows a small discrepancy in that alignment.


Alignment Coupler   A component that is installed between the Ram and the end of the Cylinder rod that allows a little “wiggle room” against a requirement that the rod movement and Ram movement be in perfect alignment.


Amateur   That’s me.  I do not claim to be a professional blacksmith, fluid dynamics guru, or any kind of expert at anything….   

I’m retired… I just learn, tinker, then teach.


Back Flow   When the 4-Way Valve reverses the air flow to the Cylinder ports, incoming air direction is immediately directed to the opposite end of the Cylinder.  

The Ram still moves in the same direction it was moving for a moment (due to momentum).  This movement results in air the in the Cylinder being “pushed” back toward the incoming air.  That air is identified as back flow.  The Check Valve prevents back flow from being pushed out into the air input stream.


Ball Valve   A valve used for controlling air flow (air on or air off).  

The Venting Valve is a 1/4” NPT Ball Valve.


Blockage   An object, or damage that is interfering with airflow through an air line or a unit (such as a regulator) on that air line. 


Blocked   This is in reference to a port (on a valve) being closed.


Blocks   Stops air movement through the Air Circuit.


Bore   Internal diameter of a Cylinder.  The Cylinder used on the original Cricket has a 2” bore.

Bore size of a Cylinder is significant because it plays a major part in volume of air required to cycle the Ram.


Braking Action   Read the definition of Power Assist in this glossary. 


BSPT   British Standard Pipe Thread.  See NPT.


Butterfly Valve   A manual air valve that is opened and closed with a lever.  

The internal mechanism is a wafer that is turned to allow air to pass through it.  Butterfly Valves are used on the Cricket because they provide a reasonable “proportional” rate of air passage mapped against the distance the lever is moved.   


CFM   “Cubic Feet per Minute”…  

This is a “consumption” or a “production” term, depending upon context.  When talking about air compressors, it’s a production reference about how much air a compressor can produce (at some specific pressure).  When used in a “consumption” context, it is referring to how much air some device (such as The Cricket) needs (at a given pressure) for operation.


Check Valve   Sometimes called a “One Way Valve”.  This valve allows air to travel only one way through an air line.  

A Check Valve is used at the source air input side of the 4-Way Valve (port 1) to prevent back flow of air from the Cylinder when the 4-Way Valve switches air flow direction to reverse the direction the Ram is traveling.


Clamping   When an object is laid on the lower die and held there by pressure from the upper die using the clamping feature of the Cricket.  


Clamping Pressure   This is how much force holds an object down.  The clamping pressure will vary with the amount of pressure in the Air Circuit.  At 80 PSI, the Cricket will provide about 300 pounds of clamping pressure.


Component List  A list of parts needed to implement this Air Circuit.  This document has a section that lists the specific manufacturers and part numbers for the major parts (and generic names for connectors and hoses) used on the original Cricket.


Connectors   Hose barb fittings, quick connects…  Anything that is inline used to join your air lines to equipment or one another.


Cushions  This is a technology on the end of a Cylinder (internal) that causes a gradual deceleration of the piston near the end of its stroke. This prevents the piston (in the Cylinder) from being “slammed” into the end caps on the Cylinder.

The last 3/4 of an inch of stroke (approximated) is used for this purpose.  Most cushions are adjustable (setting the rate of deceleration) by turning a small screw on the end of the Cylinder.  A Cylinder may have none, one or two cushions.  

Although they are not required, I recommend having cushions on the Cylinders used on a Cricket.  If cushions are not present, it must be assured that the piston in the Cylinder will never travel far enough to contact the end caps.


Cricket Air Circuit   The components and plumbing details used by the original Cricket Utility Air Hammer.  

Cycle, Cycling  This is in reference to the movement of the Ram.  When the Ram goes down, then comes back up, it has completed a cycle.


Cylinder Ports  Cylinders have connection points, generally with female threads, allowing access to the internals, on end caps.  Hoses or fixtures can be screwed into them to control the actions of the Cylinder.  Cylinders used on air hammers generally have NPT ports so common hose barbs can be used.


Cylinder Rod   That part of a Cylinder that can be pushed out or pulled in.  It  is connected to the piston in the Cylinder.


Directional Flow Control Valve  The main pneumatic valve that drives the Cylinder.  


Dock   Name given to the metal bar on the Ramp-Dock Assembly that the roller (wheel) on the Roller Valve is on when the Roller Valve’s lever has been pushed in during hammer operation.


Double-Acting Cylinder   A Cylinder that has ports on both ends.  Its rod is extended with pressurized air and retracted with pressurized air.  

This is in contrast with single-acting Cylinders that have only one port (on either end).  Single-acting Cylinders are retracted by either load-weight, gravity or an internal spring.


Down Stroke  When the Ram is on the way down. 


Duty Cycle   Refers to “What percentage of a unit of time” a machine can be safely or effectively used.  

For example, if a manufacturer says a machine has a duty cycle of 50%, it should only be used 5 out of every 10 minutes. 

In the context of this document, it refers to my observation that Cricket would probably have a 50% duty cycle using a compressor that can provide 4 CFM at 80 PSI.


Ease of Manufacturing   This phrase is used to explain why the 4-Way Valve has five ports.  

A 4-Way Valve could be designed to only have 4 Ports… 

Port for input air to 4-Way Valve.
Port for output to the front of a Cylinder port.
Port for output to the back of a Cylinder port. 
Port to Exhaust the air pushed back from the Cylinder when the Ram changes direction. 

To support this, the internal configuration of the 4-Way Valve would be much more complicated.  Adding the 5th port greatly simplifies the manufacturing process.

The 5 port, 4-Way Valve on the Cricket is plumbed to use 2 ports for exhausting air from the Cylinder. 


Elbow    A fitting that provides a 90 degree turn in a plumbing configuration.  


End Caps   The end components of a Cylinder.  


Exhaust, Exhaust Side   This is in reference to the side of the Air Circuit where pressurized air exits through Butterfly Valve 2 (and moves on to the Muffler).

Ferrous Metal   Metal that will rust…  Such as steel or iron.


Fittings    Components used to interface to hoses or additional equipment.  Examples would be the hose barbs used in ports that hoses are put on.  


Free-Flow   Allowing air movement without interruption.


Front End Cap, Front Port    The physical end of the Cylinder where the rod exits.


General Forging   Using the size stock and forging techniques you normally use.


Guidance System   The part of the Ram assembly that slides on the tower.


GULP   The amount of air it takes to cycle the Ram once.


Gulp Tank   A supplemental air tank, to be placed close to your hammer.  


Hose Connector   A barbed fitting that a hose is pushed onto. 


Internal Bore   Inside diameter of the Cylinder.


Internal Piston   A disc within the Cylinder the rod is connected to.  The piston is pushed toward one end or the other within the Cylinder via pressurized air, moving the rod either in or out.


Internal Spring  This is in reference to the springs in the 4-Way Valve or the Roller Valve that holds a spool in its normal position.


In Unison  This is in reference to two objects, connected to one another, moving together as a result of a single motion.


Kinyon Air Circuit  An Air Circuit scheme introduced by Ron Kinyon in the early 1990s.   The cricket Air Circuit uses the basic plumbing of the Kinyon Air Circuit with some improvements for performance and features.


Length of the Stroke  How far the Ram travels (up or down) during cycling.


Linkage   Objects (Metal rods, chain, etc) used to connect objects together.  There is “chain linkage” between the treadle and Butterfly Valve 2 so when the treadle is moved, the lever on Butterfly Valve 2 opens or closes.


Metered, Metering  This is in reference to controlling the amount of pressurized air (volume) entering the Air Circuit by opening or closing Butterfly Valve 2 using the treadle.

Note:  The pressurized air is actually entering the Air Circuit through Butterfly Valve 1.  Butterfly Valve 2 is “allowing” that air to enter by provide an exhaust point for it.


Momentum   Energy that keeps an object moving forward.


Mechanically   In the context of this document, this is in reference to opening a valve by hand.

It also is in reference to the lever on the Roller Valve being activated by the movement of the lever, which pushes in a plunger to change the position of the spool in the Roller Valve.


Muffler   An object that reduces exhaust noise. 


Nipple   A short threaded piece of pipe.  

Normal  The default position of a spool in an air valve when there is no external force applied to change its position.


NPT, NPT Ports   NPT is an abbreviation for National Pipe Thread.  It’s a standard for the threads on the end of pipe.  Many Cylinders have female NPT threads on the end caps on the Cylinder where the hoses are connected.  Thread pitch is 60 degrees

Be aware of BSPT, which is British Standard Pipe Thread.  Thread pitch is 55 degrees.  Threads per Inch are the same as NPT.

When you order or buy fittings, be sure you know what you are buying.  A mix of NPT and BSPT fittings can be used (not recommended) , but a sealant must be used or they will leak. 


Nominal Center of the Stroke   This is the Ram position when the Roller Valve is ascending or descending the Ramp.  

Where a signal is sent to the 4-Way Valve’s  Spool Control Port. 


Non-Ferrous Metal   In the context of this document…  Metal that will not rust, such as brass or bronze.


Norgren   Is a manufacturer and seller of pneumatic products.


Normal Position   In reference to where a spool resides (in a multi-position valve) if some outside force hasn’t moved it to an alternate position.


One-Way Check Valve, One-Way Valve   Device that allows air to flow in one direction only.


Opened Manually  By hand.


Outflow of Air   Air that is exiting the valve.


Parker   Is a manufacturer and seller of pneumatic products.


Part Number   A number assigned to an object by a manufacture or distributor.


Piston   This is in reference to the internal part of the Cylinder that air pushes against to move the rod in or out. 


Planishing   Hitting a forged object softly to smooth it (while cycling the Ram).


Plumbing   How hoses and fittings are configured and connected in an Air Circuit.


Plunger   A button on the side of a valve that is pushed in to change the position of the spool.


Plumbed   In reference to how components are connected together with hoses or fittings.


Port  An entry or exit point (for pressurized air) on a valve or Cylinder (usually with female threads).


Position of the Stroke   This is in reference to where the Nominal Center of the Stroke has been set by the Stroke Adjustment Assembly.

The Position of the Stroke can also defined as the range of motion the Ram travels during one cycle.


Positions   In reference to how many places the spool (in an air valve) can be moved to.  The 4-way and Roller Valve spools in this air circuit both have 2 positions (normal and working).


Positioned   The center of the stroke can be moved using the Stroke Adjustment Assembly.  The term “positioned” is in reference to “where” the center of the stroke resides.


Power Assist   This is in reference to the action provided by trapped air that is compressed in the air Cylinder due to to the Ram continuing to move in the same direction after the 4-Way Valve has switched air flow to the Cylinder.  


Pneumatic Valve   A valve that controls the flow of air.  


Pressure Drop   Loss of air pressure across some length of hose.  


Pressurized Air   Air that has been compressed.


Pressurized Air Line  A hose or pipe with pressurized air in it.


Pressurizing   Opening a valve and letting pressurized air to enter.

Proportional Valve   An air valve that provides proportional air flow (volume) mapped against lever movement.  


PSI   Pounds per Square Inch.  A measurement of the force air has after being compressed.


Quick Connects   Fittings that allow you to easily “connect” or “dis-connect” hoses or fixtures together.


Ram   The object that is functions as a “hammer” on a power hammer.  


Ram Assembly   An integrated unit of the Cricket that includes the Ram and its guidance system.  This unit slides up and down a tower that sits adjacent to the anvil.


Ramp   The inclined plane the wheel (on the Roller Valve) climbs or descends.


Rate of Deceleration  If a cylinder has cushions, this is in reference to how long it takes for the piston to stop if it moves all the way to the end cap of the Cylinder.  Obviously, if the piston hit the end cap at the speed it moves the Ram, it would not be a good thing.  

To avoid damage, cushions can be used to slow down the piston as it approaches the end cap.  The rate of deceleration can usually be set by turning a small screw on the end cap (cushion adjustment).


Rear End Cap, Rear of Double Acting Cylinder   The end of the Cylinder opposite to where the Rod exits.


Release, Released   If the reference is associated with the treadle, it means the operator’s foot is raised slowly to allow the treadle to move to its upper-most position.

When the reference is related to pressurized air, it means that the pressurized air is vented or released.


Reversal of the Hoses   In reference to discussions about whether or not this Air Circuit may be used with Utility Air Hammer designs that have the Cylinder over the Ram.  The answer is yes, but the hose connections from the 4-Way Valve must be reversed.  This means the hose that was connected to the front of the Cylinder would be moved to the rear of the Cylinder…  AND…  the hose that was connected to the rear of the Cylinder would be moved to the front of the Cylinder.


Roller  The wheel on the end of the lever on the Roller Valve.


Roller Valve   A 3-Way 2-Position air valve with an external lever (with a roller on the end) that is used to detect when the movement of the Ram needs to be reversed.


Stroke Adjustment Assembly   The fabricated component of the Cricket that allows the operator to move the Position of the Stroke.


Signal   This is in reference to actions performed by the Roller Valve that result in the 4-Way Valve moving it’s internal spool.  


Signal to move to the spool’s  working position…  Send pressurized air to the Spool Control Port


Signal to move the 4-Way Valves spool to its normal position…  Release the pressurized air already in the hose attached to the Spool Control Port.

The roller valve sends these signals when its roller moves up or down the Ramp.


Single-Hit   This feature provides the capability to initiate a single downward stroke with the Ram.  

The force of the blow is affected by the speed at which the treadle is pressed.


Single-Hit and Clamp Mode, Single-Hit Mode  This is a feature of the Cricket 

If the Stroke Adjustment Assembly is moved down to its lowest possible position, pressing the treadle will result in a single blow.  

If the treadle is held all the way down, the Ram will remained pressed against the lower die (or the object on the die) with significant force (at 80 PSI, about 300#).  

When the treadle is released fully, the Ram will rise to it upper-most position.


Solenoid Activated Valves   Air valves that use electricity to activate (Ex…  open a passageway or move a spool).


Stroke   Movement of the Ram (Up or down).


Stroke Length   How far the Ram travels (while cycling) before it reverses direction.  

This will vary proportionally to how far the treadle is pushed down.  

Pressing the treadle down a little causes a short stroke…  

Pressing the treadle down a lot causes a longer stroke.


Soft Blows   The Ram is cycling slowly and hits the forged object gently.


Spool   A mechanism in an air valve that controls how air moves through the valve (it configures the air passages).


Spool Control Port   A port on the 4-Way Valve where pressurized air is presented to change the position of the spool.


Tee   A fitting that facilitates three hoses or pipes to be joined together.


Tooling   Hand held tools used with a power hammer to forge objects.  

For example, a punch.


Tower   A component of the Cricket that an assembly slides on.  There are two towers on the Cricket.  

One is a component of the Frame, used by the Ram Assembly, the other is below the table and is used by the Stroke Adjustment Assembly.


Trapped Air   Air that remains trapped in the Cylinder after Butterfly Valve 1 is shut off when the Cricket is shutdown.  

This air remains in the Cylinder because of the Check Valve.  It is released by opening the Venting Valve.  As this air is released, the Ram will move down to the lower die.

The Venting Valve should be opened slowly.


Treadle   An assembly (usually a “ring” around the sides and front of the hammer base) that is pressed down (and let up) by your foot to control the cycling of the Ram.  On the Cricket, a chain is used as linkage from the treadle to Butterfly Valve 2 and the Air Gate.


Utility Air Hammer   An air hammer that requires an external compressed air source.  


Upper-Most Position   The highest position the Ram or treadle can ascend to. 


Upstroke   The upwards portion of a Ram cycle.


Venting Valve   This is a ball valve used to release compressed air from the Cylinder after Butterfly Valve 1 is closed at shutdown.


Volume of Air   This is in reference to the amount of air moving through the Cricket Air Circuit.  


Wafer  A round flat object in a butterfly valve that is turned with a lever to allow air to pass through the valve.


Water Eliminator   A device installed in an air line that removes moisture from passing air.


Wiggle Room   Describes the amount of mis-alignment that can be present between the Ram and Cylinder rod without causing excessive stress when the Ram is cycled.


Working Position   One of the two positions a spool occupies (internal on an air valve)


Next Section     Previous