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Flange Facing Machines: Definitions Listed A to Z

flange-facing-machine-a-to-z

If you're an in-situ machining or flange facing facing 'newbie' - the terminology used by flange facing machine manufacturers and on-site engineers might seem a little daunting at first.  That's why we've put together this A to Z list of abbreviations and terminology which we hope will help you - whether you're trying to choosing the right machine, or if you simply want to top up your machining knowledge. Here's what we came up with listed alphabetically.

 ASME - The American Society of Mechanical Engineers. The leading international developer of codes and standards associated with the art, science, and practice of mechanical engineering. For flange facing standards - refer to ASME B16.5 Pipe Flanges and Flanged Fittings. 

Air Lubricator - A unit used with pneumatically driven flange facing machines.

Back Facing - Machining the back face of a heat exchanger flange.

Base - Internally mounted flange facing machines have a base for attaching clamping legs.

Boring - an extra operation possible with some flange facing machines. This is needed when machining grooves for Ring Type Flange Joints.

Bearing  - an important part of an internal mount flange facer. The quality of the bearing has a strong impact on the stability of the facing arm.

Compact Flange -  A type of flange common in the oil and gas industry. The compact flange has a sealing surface with a slightly angled face. To save space, it uses a sealing ring instead of a flat gasket.

Counter Balance - used with internal mount flange facers when used in the vertical orientation. A balanced machine will maintain the same cutting speed throughout a full 360 degree rotation.

Carriage - the moving block on a facing arm that the tool post is attached to.

Down Feed - the amount of travel in the Z axis. Used to apply a depth of cut.

DTI - Dial test Indicator. Used when setting up a flange facing machine to check levelling.

Drive Hub - The central unit used to drive rotation of the facing arm.

Extension - Extra legs attached to the base when mounting inside a large flange bore.

Facing - what a flange facer does. Removing  the top surface of a flange to create a fresh and flat sealing surface. 

Feed - The rate at which the cutting tool is applied to the job.

Feet - The blocks attached to the legs used to grip the internal bore. Sometimes referred to as gripper blocks.

Flank Wear - The wear taking place on the flank face of a single point cutting tool.

Gripper blocks - See 'Feet' above.

Gib Strip - wear strip/spacer used in a facing arm.

Grooves per inch - exactly as described. The amount of grooves per inch on the flange surface. The less the number the more coarse the finish is.

Gearbox - You know what a gearbox is.  In a flange facer it's used to select the direction of travel and how coarse the finish is.

Handwheel - used on the top of a tool post to apply a depth of cut.

Hydraulic drive - an option available on many flange facers as an alternative to pneumatic.

IBC - Inner bolt circle - a type of gasket use don raised face flanges.

In - The direction in which the tool post traverses towards the center of the bore. 

Jaws - Used to clamp to the flange - See Feet and Gripper blocks above.

Lubricator - same as air lubricator above.

Mast - the top of the central hub on an internal mount flange facing machine.

Machinability- As you would expect - how easy the metal is to machine - find out more in this article

Motor -available for flange facers in either pneumatic or hydraulic.

Nose Radius - on a cutting tool insert this is the radius generated at the intersection of the leading and trailing edges of the tool. A larger nose radius is needed for a wider groove.

Nominal Size - The size used on pipes and flanges for identification only and not necessarily the exact dimension. 

OD - outside diameter - example OD mount flange facing machine

Out - The direction in which the tool post traverses towards the outside edge of the flange.

Pneumatic - A drive option for a flange facer.

Power Pack - A hydraulic unit used to deliver supply to the machine.  Diesel driven and capable of operating in remote locations with no air line or electric power.

Quality - There's not too many Qs relating  to flange facing - but quality is important. If you buy a cheap machine the quality of your work will suffer. A false economy.

Raised Face - A common type of flange which required a spiral serrated finish to ensure joint integrity.

RTJ - Ring Type Joint.  These flange joint use a metal ring unlike raised face flanges which often use flat spiral wound gaskets. They are used for high pressure oil and gas applications.

RMS - Root Mean Square -  A mathematical measure of the average roughness of a surface.

Setting Straps - Used to hold the machine in place during base installation. These are removed when the assembly has been secured and is confirmed as level.

Spiral Serrated - The finish created by a flange facer. Other names are phonographic finish and gramophone finish.

Slide ways -  These are the hardened steel rails that the carriage travels across.  An important component that ensures stability of the tool post.

Surface Comparator - A handy reference kit with example surface finishes.

Swing Diameter - The dimension used to check the machine will not hit any obstructions when rotating in-situ.

Tool Post - used to hold the tooling assembly. These can usually swivel and include a handwheel to apply a depth of cut.

V -rails - same a slide ways mentioned above

Vessel - A vessel in the oil, gas and petrochemicals is used to store liquids which are often hazardous.  Vessels have flanges connected to them which need a secure joint.

Waviness - This is different to surface roughness - think of it as recurrent irregularities in the form of waves on which roughness is superimposed.

Want to find out more? Get in touch here or download our guide.

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