Key Stock and Machine Keys

Shop By Key Stock or Machine Key Type

Undersize Machine Keys

Oversize Machine Keys

Bilateral Machine Keys

Round Keys

Hex Keys

Alloy 400 Machine Keys

Mil-Spec Machine Keys

Key Stock Assortments

Key Stock , or bright steel, is a general term for a stock of square or rectangular bars 12 inches or longer in length from which machine keys are produced. Key Stock is cold drawn to exacting tolerances with sharp corners, perpendicular and parallel sides, and smooth, bright surface finishes. Hex, round, and step profiles are available to mate with a variety of gears, key ways, sprockets, or other assembly components. Depending on their use, hex and round profiles are sometimes called shafting, just as cut-to-size key stock is commonly referred to as machine keys.

Available in Oversize, Undersize, Bilateral, Step, Hex, and Round types
Offered in Carbon Steel, Stainless Steel, Aluminum, Brass, Copper, Nylon, and PVC
Cold drawn for improved yield strength and tighter tolerances

Bilateral Key Stock

Bilateral Key Stock is key stock 12 inches or greater in length with an actual size that will be slightly under or over a specified range within the acceptable tolerance range. Bilateral key stock is typically used in field applications for repair and is the most desirable grade for maintenance repair operations. Huyett manufactures key stock to suit every application need you have, in every size, grade and tolerance imaginable. Available in stocked standard sizes or custom made to your specifications.

Available in Aluminum, Brass, Carbon Steel, Stainless Steel, and Nylon
Offered in corrosion resistant Zinc Clear finish
Cold drawn for tighter tolerances and a uniform finish

Oversize Key Stock

Oversize key stock is key stock 12 inches or greater in length with an actual size slightly larger than a specified size while remaining within an acceptable tolerance range. Oversize key stock is most popular in original equipment manufacturing due to precision finish and tight fit in the key way. Huyett manufactures key stock to suit every application need you have, in every size, grade and tolerance imaginable. Available in stocked standard sizes or custom made to your specifications.

Available in Carbon Steel and Stainless Steel
Offered in corrosion resistant Zinc Clear finish
Cold drawn for more precise measurements and improved surface finish

Undersize Key Stock

Undersize key stock is key stock 12 inches or greater in length with an actual size slightly smaller than a specified size while remaining within an acceptable tolerance range. Undersize key stock is commonly used in field applications for repair with little or no filing needed. Huyett manufactures key stock to suit every application need you have, in every size, grade and tolerance imaginable. Available in stocked standard sizes or custom made to your specifications.

Available in Carbon Steel, Stainless Steel, and Copper
Offered in corrosion resistant Zinc Clear and Zinc Yellow
Cold drawn for improved yield strength and more precise tolerances

Step Key Stock

Step key stock, sometimes called repair key stock, is commonly used when worn or damaged key ways have been repaired. Step Key stock is milled into a T-Shape design and is offered as Type 1 or Type 2. Type 1 is designed for use in key ways of repaired gears, sprockets, pulleys, and other hub assembly components. Type 2 is designed for use in repaired shaft key ways.

Offered in Carbon Steel and Stainless Steel materials
Available in corrosion resistant Zinc Clear finish
Cold drawn for tighter tolerances and improved yield strength

Hex Key Stock

Hex key stock, sometimes called hexagon shaft, hex shaft stock, or hex stock, is frequently used for tool shafts, tool steel, drill bits, transmission shafts, axles, machine mounts, and gearbox output shafts. Due to its shape, Hex key stock does not need a key or key way to secure the shaft to a hub or gear, thus saving costs in machining time. When cutting hex keys from this key stock, size is measured across the parallel flats of the bar.

Available in Brass, Carbon Steel, and Stainless Steel
Offered in corrosion resistant Zinc Clear
Torque load is distributed across six points of contact when used as a shaft

Round Key Stock

Round key stock, sometimes called round linear shaft, round bar, or round stock, is a versatile material. It is often used as shafting, straight pins, rails, or for locating in a wide range of applications and industries. Round key stock is also used as a rotating device and can be easily welded, machined, or fabricated.

Available in Aluminum, Brass, Carbon Steel, Stainless Steel, Nylon, and PVC materials
Offered in Zinc Clear and Zinc Yellow corrosion resistant finishes
Inch and Metric sizes available

Key Stock Assortments

Key stock assortments are maintenance kits containing various sized key stock cut into more manageable 12 inch (305mm) lengths to accommodate commonly used key sizes. Key stock assortments can be used in a variety of applications such as bin stocking, customer sampling, or as point of sale displays. Huyett is a proud distributor of Mak‑A‑Key® key stock assortments.

Available in Carbon Steel and Stainless Steel materials
Offered in Zinc Clear and Zinc Yellow
Key stock assortment options in Oversize, Undersize, and Bilateral

Alloy 400 Key Stock

Alloy 400, often referred to as Monel®, key stock is precision key stock manufactured from cupronickel alloy. In appearance, the copper nickel alloy looks very similar to stainless steel but possesses a pinkish hue. Alloy 400 key stock is extremely durable in low temperatures and possesses excellent resistance to a variety of corrosive media. These features make alloy 400 key stock desirable for making machine keys intended for marine applications, chemical processing equipment, and the oil and gas industry.

Offered in Mak‑A‑Key® assortments, it can easily be cut and filed to fit using simple hand tools
Possesses great mechanical properties in sub‑zero temperatures
Superb corrosion resistance against salt water, sulphuric acid, and alkalis

Mil-Spec Key Stock

MIL‑SPEC compliant key stock is precision manufactured to the most exacting specifications. The raw material is procured from DFARS qualifying countries in accordance with Article 252.225‑7009. Available in 1ft and 3ft lengths, MIL‑SPEC compliant key stock can be cut to match lengths listed in most standards including NASM20065, NASM20066, and NASM20068.

Offered in Mak‑A‑Key® assortments for easy cutting in the field with simple hand tools
"Ready‑now" production and stock availability
Defense Federal Acquisition Regulation Supplement (DFARS) compliant

Machine Keys , also known as shaft keys, are removable machine elements installed between shaft key seats and hub key ways. They are used to transmit torque from the rotating shaft to a gear or sprocket and are specifically designed to fail as a safety mechanism to save more expensive components. Though simple in design, these parts are essential for the transmission of power. Machine keys can be finished in a variety of shapes, sizes, and materials for almost any application, however they are most common with both ends round (Form A), both ends square (Form B), or one end round and one end square (Form AB).

Can be designed with dimensional features like set screws and other attributes
Tensile strength, shear strength, and wear resistance can be enhanced
Standard sizes are ready to use with little or no cutting or filing

Woodruff Keys

Woodruff keys, also called half-moon keys, are commonly found in machine tools and automotive applications. They are designed to be installed deep into a shaft and remain firmly embedded. This allows the key to withstand great strain and is not prone to rolling over in the key seat like ordinary machine keys. They are often used to avoid milling a key seat near stress concentration prone shaft shoulders at the end of a shaft.

Offered in Alloy Steel, Carbon Steel, and Stainless Steel
Corrosion resistant coatings include Passivated, Zinc Clear, and Zinc Yellow
Economical half-moon design cuts down milling costs
Both round and flat bottoms are standard and function equally

Hi-Pro Keys

Hi-Pro keys, or high profile keys, are a variation woodruff keys with the added feature of “feet.” These feet keep the key from rocking in the key way while still allowing it to adjust to angular spines. This design also allows the key to be installed quickly and accurately thus improving assembly efficiency. Hi-pro keys are commonly used to lock pulleys and gears to transmission shafts.

Offered in corrosion resistant Zinc Clear finish
Available in Alloy Steel, Carbon Steel, and Stainless Steel
Cold drawn for tighter tolerances

Gib Head Keys

Gib keys, or Gib head keys, are tapered and notched machine keys that are used on power transmission keyed shafts to hold pulleys and gears tightly on the shaft. The head of the key serves as a concussion point for hammering without damage to the shaft of the key. The added feature of the head also allows for easier removal of the key.

Available with corrosion resistant Zinc Clear finish
Offered in Low Carbon Steel
Common taper is 1/8 taper per foot

Undersize Machine Keys

Undersize machine keys are cut from key stock to lengths under 12 inches long. Undersize indicates that the key is either at or slightly smaller than a specified size while remaining within the tolerance range. Just as with other machine keys, undersize machine keys hold machinery parts in place or align components and normally fit without the need to file. They are specifically designed to fail as a safety mechanism to save more expensive components. Standard sizes are ready to use without any cutting or filing.

Available in Carbon Steel and Stainless Steel
Offered in corrosion resistant Zinc Clear finish
Undersize machine keys are relatively free fitting

Oversize Machine Keys

Oversize machine keys, or broad machine keys, are cut from key stock to lengths under 12 inches long. Oversize indicates that the key is either at or slightly larger than a specified size while remaining within the tolerance range. These machine keys are often used when a custom fit is needed or desired for an oversize key way. They are also used in field repairs and for worn key ways. They are specifically designed to fail as a safety mechanism to save more expensive components. Standard sizes are ready to use without any cutting or filing.

Available in Carbon Steel and Stainless Steel
Offered in corrosion resistant Zinc Clear finish
All machine keys are RoHS compliant

Bilateral Machine Keys

Bilateral machine keys are cut from key stock to lengths under 12 inches long. Bilateral indicates that the key’s tolerance can be slightly larger or slightly smaller than a specified size while remaining within the tolerance range. While these keys do not match ANSI spec, they tend to be the most desirable grade in maintenance repair operations. They are specifically designed to fail as a safety mechanism to save more expensive components. Standard sizes are ready to use without any cutting or filing.

Available in Carbon Steel, Stainless Steel, Monel, Brass, and Aluminum
Offered in Inch or Metric sizes
All machine keys are RoHS compliant

Round Keys

Round keys, also called pin keys or round machine keys, are cylindrical keys inserted into a cylindrical key way that has been drilled and reamed partly in the shaft and partly in the hub while the application is assembled. A tight interference fit is required between the key and the key way to ensure uniformity along the length of the key.

Offered in Carbon Steel and Stainless Steel
Available in both Inch and Metric sizes
Lower stress concentration as compared to other key designs

Hex Keys

Hex keys are machine keys cut from hex key stock to lengths under 12 inches and are typically considered undersize. Hex keys are used in a variety of applications from tools to drive shafts in gear boxes.

Available in Carbon Steel
Hex size is measured across parallel flats

Alloy 400 Machine Keys

Alloy 400, commonly referred to as Monel®, machine keys are made from precision, copper nickel alloy key stock. These machine keys are typically less than 12 inches long and possess an appearance similar to stainless steel. Alloy 400 machine keys possess excellent corrosion resistance qualities as well as great mechanical properties in subzero temperatures. Alloy 400 machine keys are suitable for power transmission components in marine and chemical processing applications.

Excellent corrosion resistance to salt water, sulphuric acid, and alkalis
Retains strength and shape up to 1300° C
Defense Federal Acquisition Regulation Supplement (DFARS) compliant

Mil-Spec Machine Keys

MIL‑SPEC machine keys refer to a special class of machine keys that conform or aligns with specifications for products used in the military and aerospace industries. These keys serve as a failure point to minimize damage in the event that a power transmission component fails. MIL‑SPEC machine keys are manufactured from bright steel bars that are keyway‑ready after being cut to precise tolerances. Huyett's MIL‑SPEC machine keys are designed to conform to all known and relevant military, aerospace, and government standards for machine keys.

Manufactured in the USA to tight tolerances
Available in Form A, Form B, and Form AB variations
Defense Federal Acquisition Regulation Supplement (DFARS) compliant

What is key stock?

Key stock, or bright steel, is a general term for a stock of square or rectangular bars 12 inches or longer in length from which machine keys are produced. Key stock and bar stock are frequently used interchangeably, however there is a difference. Key stock is cold drawn to exacting tolerances with sharp corners, perpendicular and parallel sides, and smooth, bright surface finishes. Bar stock is typically hot rolled and does not hold as tight of tolerances as key stock. Key stock can be manufactured in hex, round, step, square, and rectangle profiles to mate with a variety of gears, key ways, sprockets, or other assembly components. For more information about what key stock is and how it is used check out our blog!

Where can I buy key stock?

Huyett is a manufacturer of key stock with over one million pounds of material on hand. Our state-of-the-art manufacturing facility can cut key stock to any length and form for your specific needs. Huyett is also a proud manufacturer of MAK‑A‑KEY®, the oldest and most well‑known key stock brand in the world, offering stock material for aftermarket repairs and maintenance of power transmission components.

Where can I buy machine keys?

As the market leader in power transmission components, Huyett offers the widest variety of machine keys in the industry. If you don’t see the machine key for your specific application, contact our friendly, experienced customer service team for a custom design. Our state‑of‑the‑art manufacturing facility can produce machine keys in any size, form, grade, and tolerance imaginable.

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What is key stock used for?

Key stock has a wide variety of uses. Square, rectangle, and step key stock are the most common profiles used to make machine keys. These machine keys, also known as shaft keys, secure a rotating shaft to a gear or hub assembly for transmitting power to a mechanical component.

Round key stock, not to be confused with drill rod, may be used as shafting and/or cut to length machine keys. Compared to square keys, this design results in lower stress concentration making it appropriate for lower power applications such as fastening a collar and pulley to a shaft.

Hex key stock is frequently used for tool shafts, tool steel, drill bits, transmission shafts, axles, machine mounts, and gearbox output shafts.

What are shaft keys made of?

Key stock is made from a wide variety of materials. Carbon steel and stainless steel are the most common materials used for making key stock, however materials such as monel, aluminum, brass, copper and nylon are also used.

Key stock is also made from moltrup, or moltrip, quality steel. This quality of steel is often requested for original equipment manufacturing due to its tight tolerances. For more information on key stock materials check out our blog!

How do you cut key stock?

Key stock is commonly cut for use as shaft keys, commonly referred to as machine keys using a variety of saws or cut-off discs. For in field applications, key stock is generally cut using a hack saw and filed to the desired form and fit. Huyett can cut key stock to specific lengths using state of the art equipment allowing for precise, finished products.

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What is oversized key stock?

What is a shaft key?

Shaft Keys, also known as machine keys, are removable machine elements installed between shaft key seats and hub key ways. They are used to transmit torque from the rotating shaft to a gear or sprocket and are specifically designed to fail as a safety mechanism to save more expensive components. Though simple in design, these parts are essential for the transmission of power. Machine keys can be finished in a variety of shapes, sizes, and materials for almost any application, however they are most common with both ends round (Form A), both ends square (Form B), or one end round and one end square (Form AB).

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How does a shaft key work?

Shaft keys, or machine keys, work by securing a rotating shaft to a hub assembly or gear thus transmitting torque from the shaft to a gear or sprocket. In normal operation, a keyed assembly allows primary gears and drives shafts to turn together. However, if forces exceed design limits, the machine key may shear preventing damage to other components. Machine keys effectively act as safety stops to protect expensive mechanical components.

How do you make a shaft key?

Shaft keys, commonly called machine keys, are made from key stock (bright steel). The key stock is cut to lengths 12 inches or less using a saw. Depending on the required machine key form, filing may be required for fitment into the desired key way. Huyett has state of the art equipment to manufacture machine keys to precise tolerances. Huyett is also a proud distributor of Mak‑A‑Key® assortments for easier in-field key cutting.

Which key is used for fitting taper shaft?

Woodruff keys, sometimes called half-moon keys, are frequently used in applications with taper shafts. The half-moon design allows the key to adjust to the angle of the spine while being installed. The key operates the same in a tapered shaft as a non-tapered shaft, whereas it seats deep in the shaft, remaining firmly embedded.

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What is a woodruff key?

How are woodruff keys measured?

Woodruff keys, identifiable by their half-moon shape, are measured two ways depending on if it is an imperial or metric key. Imperial woodruff keys are measured by their width and diameter, whereas metric woodruff keys are measured by their width and height. ANSI b17.2 – 1967, R1990 can be referenced for measuring standard woodruff keys.

What are woodruff keys used for?

Woodruff keys, also called half-moon keys, are often used in stress prone applications where milling a key seat near shaft shoulders at the end of a shaft should be avoided. These keys are found in lawn and garden equipment, automobiles, pumps, electric motors and more. Regardless of the application, the keys primary function is the same, to transfer torque from a rotating shaft to a gear or hub assembly.

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What is a step key?

Step keys, sometimes called repair key stock, are commonly used when worn or damaged key ways have been repaired. Step Key stock is milled into a T-Shape design and is offered as Type 1 or Type 2. Type 1 is designed for use in key ways of repaired gears, sprockets, pulleys, and other hub assembly components. Type 2 is designed for use in repaired shaft key ways.

How to measure a step key?

Transcript: Let's measure a Step Key. There are two types of step keys: type 1 and type 2. Both are identified using 4 measurements. First measure the width on both the thick and thin side of the key. Then measure the height from above and below the step on the key. There you have it. It's that simple to measure either a type 1 or type 2 step key. Thanks for watching!

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How to install a shaft key

Shaft keys, known as machine keys or industrial keys, are installed by placing the key in the key way of a shaft, gear, or hub assembly. There are three types of fitment to take into consideration when installing a shaft key into a key way.

Class 1: Clearance Fit – In a clearance fit, the key will be slightly smaller than the key way allowing the shaft and the component to be slid over each other.
Class 2: Transition Fit – In a transition fit, the key width and the key way can have a slight clearance fit or a slight interference fit. Generally this fit is sufficient to hold mating parts together while still allowing for disassembly.
Class 3: Interference Fit – In an interference fit, the key will be larger than the key way and will encounter interference during installation. Some means of force or temperature change is required for installation.

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How to remove a stuck key from a shaft

Shaft keys (machine keys) may become stuck or seized in their key way. There are numerous methods of extracting stubborn keys from their key ways, however these are the most common. Care must be taken with each of these methods to not mar the surface of the shaft or compromise its integrity.

End Cutting or Side Cutting Pliers – Using end cutting or side cutting pliers, firmly grasp the exposed portion of the machine key allowing the cutting edge of the pliers’ jaws to grip the key. Next, begin rocking the key back and forth while at the same time pulling up. Continue until the key releases from the key way.
Adjustable Locking Pliers – This method is similar to using end cutting or side cutting pliers, however the adjustable locking pliers provide a much more secure grip. Adjust the pliers to securely grip the key and lock into place. Once a secure hold is established, rock the key back and forth until the machine key is freed from the key way.
Slide Hammer w/ Locking Plier Attachment – Secure the adjustable locking pliers securely to the machine key. Next attach the slide hammer to the locking pliers and begin sliding the weight up the shaft of the slide hammer striking it against the stop. Do this repeatedly until the machine key breaks free.
Hammer / Chisel or Punch – For open ended key ways, place the punch or chisel at the end of the machine key at the closed end of the key way. Strike the punch or chisel with a hammer to break the machine key loose. For woodruff keys, place a punch at one of end of the key striking the punch downward to force the end of the key down into the shaft. The half-moon shape allows the key to slide in its slot, forcing the opposite end up.
Welder and Slide Hammer – Weld a bolt, pin, or other extruding piece of metal to the machine key. Next attach a slide hammer to the extrusion and begin sliding the weight up the shaft of the slide hammer striking it against the stop. This transfer of force in combination of the heat created by welding assist with jarring the key loose.

What are the different machine key types?

Machine keys, commonly called shaft keys, can be finished in a variety of shapes, sizes, and materials for almost any application. Some common machine keys are “T” shaped step keys, round keys, and hex keys, however the most widely used machine keys are square and rectangle keys. These keys are typically available in three different forms referenced as Form A, Form B, and Form AB. Form A keys have rounded ends that fit the contour of a key way machined with fully radiused ends. Form B machine keys have both ends square and Form AB keys have both a squared end and radiused end.

How to cut a key slot in a shaft

A key slot, most commonly called a key way, can be cut into a shaft by broaching, electrical discharge machining (EDM), milling, and shaping/slotting.

Broaching is a machining process that uses a cutting tool called a broach to remove material. There are two types of broaching used, linear and rotary. Linear broaching is the most common method of broaching where the broach is run linearly against the shaft creating a key way the entire length of the shaft or hub. Rotary, while less common, involves a rotating tool that is pressed into the work piece. Rotary broaching can create full length key ways as well as blind key ways.

Electrical Discharge Machining (EDM) uses an electrically charged wire to displace material. EDM is a highly accurate method of machining keyways, however due to it slower process, it is typically used for shorter runs or made-to-order applications.

The Shaping/Slotting machining process works well for machining blind key ways or external key ways that do not traverse the entire length of a shaft. Shaping or slotting is also a viable solution for machining internal key ways like those found on gears or hub assemblies.

Milling is similar to shaping as it allows a keyway to be cut the partial length of a shaft or hub, however milling uses a rotary cutter as opposed to a fixed bit. Milling is commonly used for external keyway applications rather than internal keyways due to clearance and interference conflicts from the milling machine.

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What is Mil-Spec?

“Mil Spec,” sometimes called MilSpec or Mil-Spec is an abbreviated term for Military Specification that refers to a series of specifications and requirements used to help standardize objectives by the Department of Defense (DoD). American and French militaries were early adopters and sponsors of standardization and interchangeability in the early 1900s.

Mil-Spec machine keys refer to a class of machine keys that conform or align with specifications for products used in the military and aerospace industries. These specifications include MS20065, 20066, 20067, and 20068. All Mil-Spec machine keys designed and manufactured by G.L Huyett conform to all known and relevant military, aerospace, and government standards for machine keys.

What is Monel®?

Monel, also called Monel 400, is a trademarked name often used to refer to a cupronickel alloy known as alloy 400. Alloy 400 is composed of approximately 63% nickel and 28-34% copper possessing excellent strength at low temperatures. This series of alloy provides good ductility and thermal conductivity as well as excellent corrosion resistance to a wide variety of corrosive media. These features of alloy 400 make it a viable solution for many applications in marine and chemical environments. It is most commonly used to make heat exchangers, valves, pumps, propellers and pump shafts.

Is Monel or Alloy 400 magnetic?

Monel, also called alloy 400 or Monel 400, is a metal alloy comprised of nickel and copper. It has a magnetic permeability of 200 oersted/1.0002 at 75°F making it slightly magnetic at room temperature.

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Nickel-Copper Alloy / Monel 400 Precision Key Stock

Transcript: Huyett has always been on the cutting edge of our industry, and we have done it again. Our MAK-A-KEY precision key stock now offers Monel 400 key stock, a more economical solution to the standard cutting of Monel plating. Our line of Monel key stock has tighter tolerances, more accurate production, and is DFARS compliant. When purchasing our beneficial Monel key stock, you are also able to get the free MTRs we provide for the key stock. It is available in many sizes, the popular ones in stock now, and we support special orders of lengths up to 12 feet. We are excited to help you and your business with the offering of a better solution to a higher tolerance and better resistant key stock. For more information, you can visit huyett.com/keystock or contact our sales team today. Thank you for watching, and we look forward to working with you soon.

How to measure a Form A machine key

Transcript: Hi! My name is John Hudson. I'm a member of the team here at Huyett. We are a cutting edge manufacturer and a master distributor of fasteners, grease fittings, and engineered parts. Let's measure a Form A machine key. The first thing you want to do is measure the shorter of the height or width. Then you want to measure the longer of the height or width, and then you want to measure end-to-end. It's that simple. You have just measured a Form A machine key. After measuring your part, visit Huyett.com. We make it easy to search for, find, and buy the parts you need by including photographs, technical drawings, material grades, and dimensions of every part. We even include quantity breaks and pricing along with the option of adding a certificate of compliance to any order. Huyett manufactures key stock and machine keys to ANSI spec B17.1. If you need a key made to a different standard or custom size, give our sales team a call or visit us at Huyett.com.

How to measure a gib head key

Transcript: Let's measure a Gib Head Key in inches. They're very simple to measure. The first thing you want to measure on one, you want to measure the width. You want to get it from right under the head there. And then you're going to measure the effective length. The effective length is going to be from under the head to the end of the key. It's that simple to measure a gib head key in inches. Thanks for watching!

How to measure a Hi-Pro key

Transcript: Let's measure a Hi-Pro Key. Hi-Pro Keys are easy to measure. There's three measurements that you'll need. You'll need the overall length of the key. You will need the width of the key. And then the last measurement you're going to need on this one is going to be the thickness of the lip. It's that simple to measure a Hi-Pro Key. Thanks for watching!