End Mill Size Standards (American)

mill drill tooling

This chart references all the standard end mill tool sizes in American measurements. Also available in PDF format to download for future reference.

Fractional Decimal Fractional Decimal
1/64 .0156 5/16 .3125
1/32 .0313 21/64 .3281
3/64 .0469 11/32 .3438
1/16 .0625 23/64 .3596
5/64 .0781 3/8 .3750
3/32 .0938 25/64 .3906
7/64 .1094 13/32 .4063
1/8 .1250 27/64 .4219
9/64 .1406 7/16 .4375
5/32 .1563 29/64 .4531
11/64 .1719 15/32 .4688
3/16 .1875 31/64 .4844
13/64 .2031 1/2 .5000
7/32 .2188 9/16 .5625
15/64 .2344 5/8 .6250
1/4 .2500 11/16 .6875
17/64 .2656 3/4 .7500
9/32 .2813 7/8 .8750
19/64 .2969 1 1.000

Want a PDF version? Click here to view and/or download.

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Choosing the Right Plastic for Your Part

Blue Plastic bottle (top view) and cap

Plastic Selection Tips for Machining

For low-volume and close tolerance applications, machining of plastics can be a cost-effective and reliable method for your projects. It is typically simpler to machine and less expensive than metal. Highly engineered plastics perform quite well under a variety of conditions, while inexpensive lower-performance versions are available for projects with less stringent requirements.

The typical engineered part requires three characteristics to function. Your search for plastics that will supply all three will come up with a list of potential materials. The information below lists the most common characteristics any engineer will need to consider when looking for a plastic that will function as required. The suggested materials serve as a starting point, and are not comprehensive.

Some plastics are available with fillers that will change the properties of the plastic to suit your needs without having to upgrade materials. However, these fillers, such as glass, may also reduce machinability.

choosing plastic for machining parts infographic


For medical devices. These plastics are able to come into contact with the human body without causing problems. Include a USP class VI designation (Biological Reactivity Testing), also regulated by ISO 10993 (Biological Evaluation of Medical Devices).

Biocompatible Plastics:

  • Radel

  • UHMW

  • Polycarbonate

  • PEEK

Chemical Resistance

Plastics in general have a wide variety of chemical resistance. Though some seem almost universally resistant, others are highly sensitive and crack when exposed to almost any chemical. Before choosing a plastic, consult a good reference guide to learn about specific interactions with chemicals.

High Chemical Resistance Plastics:

  • UHMW

  • Teflon

  • PEEK

  • CTFE

Low Chemical Resistance Plastics:

  • Acrylic

  • ABS

  • Noryl

  • Polysulfone


Stock plastic begins clear but machining generally changes them from translucent to opaque. If clearness is a requirement, polishing is necessary. Polishing methods include buffing, direct machine polish, flame polish and vapor polish.

Clear Plastics:

  • Acrylic

  • Polycarbonate

  • Clear PVC

  • Polysulfone

  • Ultem


When choosing material for your project, consider the machining and finishing costs in addition to the price of the raw material. Though usually more inexpensive than metals, higher performance engineered plastics cost more.

Inexpensive Plastics:

  • Delrin

  • UHMW

  • Polypropylene

  • HDPE

Expensive Plastics:

  • PEEK

  • Vespel

  • PPS

  • Radel

  • HDPE

Dimensional Stability

Unlike metals, machined plastics have less structural stability. They tend to absorb water and expand when exposed to heat. More stable plastics have low water absorption and a low CTFE.

Dimensionally Stable Plastics:

  • Ultem

  • PEEK

  • PPS

  • PET

Less Dimensionally Stable Plastics:

  • Nylon

  • UHMW

  • HDPE

  • LDPE


Plastics that come into contact with food, especially packaging, require approval for use by the Food and Drug Administration.

FDA Approved Plastics:

  • Delrin

  • PET

  • Polycarbonate

  • PEEK

Limiting PV

For bearing applications, plastics need a combination of pressure and velocity to give it the thermal and structural ability to withstand rotational wear.

High Limiting PV Plastics:

  • PEEK

  • Nylatron

  • Delrin AF

  • Torlon 4301

Low Limiting PV Plastics:

  • UHMW

  • PBT

  • PET

  • Nylon

Steam Sterilization

Most biocompatible plastics will hold up to this process of using steam to sterilize material prior to first use.

Plastics Compatible With Steam Sterilization:

  • Radel

  • Ultem

  • PEEK

  • Teflon


For structural applications, two types of loading strength (measured in psi) are important to consider when choosing a plastic. Tensile strength, the most widely measured, indicates the amount of pressure required to pull a sample apart from the ends, as well as the amount of stretching before the break. In compression strength tests, the opposite is tested. Samples are pressed and the amount of force necessary to break them is measured.

High Strength Plastics:

  • Ultem

  • Peek

  • PPS

  • Nylon

  • Delrin

Low Strength Plastics:

  • Teflon

  • UHMW

  • LDPE

  • HDPE

  • Polypropylene

Temperature Resistance

Two types of temperature resistance are important to machined plastic parts: the optimal air temperature, or the amount of heat deflection if under a load.

High Temperature Resistance:

  • PTFE

  • PEEK

  • Ultem

  • Torlon

  • PPS

Low Temperature Resistance:

  • Acrylic

  • UHMW

  • ABS

  • PVC

Toughness/Impact resistance

This index measures the ability of a plastic to endure a blow or sudden impact. This is not the same as continual pressure or load. Some plastics can withstand an impact but will not do well under a constant load.

High Impact Resistance Plastics:

  • Nylon

  • Polycarbonate

  • UHMW

  • PEEK

Low Impact Resistance Plastics:

  • PET

  • Acrylic

  • Noryl

  • Polysulfone

UV Resistance

Outdoor applications require a resistance to UV light. Without it, material will age and become brittle. Black plastics usually have some resistance because of color.

High UV Resistance Plastics:

  • Ultem

  • Polycarbonate (UV stabilized only)

  • PBT

Low UV Resistance:

  • Polycarbonate (FDA)

  • Nylon

  • Acetal

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The Least You Need to Know About Aluminum for Machining

cast aluminum part machined

Alum 6061

Aluminum 6061 is one of the most widely used alloy materials in machining due to its price, strength and versatility. Though Aluminum 2024 has a higher strength to weight ratio, it is not as corrosion resistant.

The ability of aluminum 6061 to withstand corrosion makes it economical because it doesn’t require finishing. Once exposed to the atmosphere, it develops a thin protective layer that protects it from surface rust.

The combination of corrosion resistance and low weight make it an economical material to use in short production runs because parts can be created faster. In addition, it is chemical resistant and easy to machine.

Parts that require multiple processes, such as machining and then welding, benefit from Aluminum 6061 because in addition to being easy to machine it is also weldable.

Aluminum 6061 Tempers

There are a variety of tempers for 6061 aluminum alloy, including:

  • 6061-F:

    No special treatment

  • 6061-O:

    Annealed, good for forming

  • 6061-T1:

    Cooled and naturally aged

  • 6061-T4, 6061-T4511:

    Heat-treated and naturally aged

  • 6061-T51:

    Cooled and artificially aged

  • 6061-T6, 6061-T6511:

    Heat-treated and artifically aged, most common alloy used in a variety of applications

  • special tempers: 


Aluminum 6061 Composition

Aluminum 6061 is composed of the following elements by percentage of weight:

  • Magnesium (0.8-1.2)
  • Silicon (0.4-0.8)
  • Iron (Max 0.7)
  • Copper (0.15-0.4)
  • Zinc (Max 0.25)
  • Titanium (Max 0.15)
  • Manganese (Max 0.15)
  • Chromium (0.04-0.35)
  • Other (0.05)
  • Aluminum (balance)

aluminum 6061 infographic: tempers, common forms, composition, applications

Aluminum 6061 Characteristics

Alloy Temper Formability Machinability Corrosion Resistant Weldability (Arc with Inert Gas) Brazeability Anodizing Response
6061 O Very High Poor Very Good Excellent Excellent N/A
6061 T1, T4, T4511 High Fair Very Good Excellent Excellent Very Good
6061 T6, T6511 Low Good Very Good Excellent Excellent Excellent

Aluminum 6061 Applications

  • aircraft wings and fuselages, not as strong as Alum 2024 but more corrosion resistant
  • boats
  • automotive parts
  • flashlights
  • cans
  • tactical flashlights
  • SCUBA tanks made after 1965
  • bicycle frames and parts (T6)
  • fly fishing reels (T6)
  • firearms (T6)
  • RC aircraft (T6)
  • welding
  • extrusions
  • forgings

For More Information About Aluminum

Fun facts from Chemicool

The Aluminum Association

Aluminium International Today


Custom Manufacturing vs. Mass Production

photo of brass components lined up on a shelf

Creating products requires different processes. Two main points of consideration include what type of production is necessary to achieve the desired results.

In manufacturing, two different ends of the spectrum are custom manufacturing and mass production. While custom parts may run into the hundreds and thousands, mass production quantities are usually much higher.

Let’s look a little closer at exactly what these processes entail.

mass production vs custom manufacturing infographic

Mass Production

mass production

When thousands or even millions of identical parts are needed, companies turn to mass production to meet their needs.

These manufacturers use a production line to create tons of identical parts on automated machines that run 24/7 with very little human interaction. Many overseas manufacturing plants operate this way. Automation is the primary means to produce parts.

Pros of Mass Production

Mass production is more cost efficient for companies producing large quantities of metal and plastic parts. Because machines do most of the work, labor costs are relatively low. Identical parts are easier to come by because everything is programmed and research-driven.

If maintaining an inventory of spare parts is important, mass production can easily provide more than necessary.

Cons of Mass Production

Human interaction on the production line is limited. If quality is an issue, there is less oversight to catch issues that appear during the process. Minimum run quantities tend to be extremely high, so waste is another issue. If a part needs design changes, it is more costly to pull something out of production to work out issues.

Custom Manufacturing

custom-manufacturing man sanding

Creating a small number of parts, or an untested part that may require design changes are both situations that work well for custom manufacturing. Because of the amount of human involvement over the course of production, quality is easier to monitor and stopping production is not as much of an issue.

Pros of Custom Manufacturing

Custom manufacturing has lower minimum quantities, if any at all. Though lower volumes will be more expensive, these parts are easier to make changes to during production.

Quality inspections are more frequent, and many times involve more than just observing the appearance for flaws. Adjustments can be made to account for quality problems that didn’t appear until production began without as much difficulty as mass production.

Cons of Custom Manufacturing

Because of the higher degree of human interaction with custom manufactured parts, the downside is a part that costs more to produce.

Less automation also means more chances for errors, but even small runs usually involve CNC machines that are programmed to create identical parts, so this isn’t a huge issue.


While mass production has some advantages, unless you’re producing parts by the millions there really isn’t much of a reason to go that route.

Custom manufacturing provides a durable part, with the option to make changes as necessary. This eliminates waste and allows you to create only as many parts are needed for a short period of time.

Have a project in mind?

Upload your file to our quote page for a hassle-free experience today!

How to Choose Material for Your Custom Manufactured Part

small round metal part manufactured

Advances in science have made a huge impact on product design and production. One important area of consideration for any product is the material or materials you choose to construct it with.

With a vast amount of materials available, how do you know which one is right for your product?

Several variables come into play, including:

  • machinability
  • price
  • availability
  • strength
  • delivery time

If your final product requires a combination of processes and assembly, things can get even trickier.

While we can’t make your decision for you, here’s a simple process to help you systematically choose the correct material for your application needs.

material selection process for manufacturing

Design Requirements

Before investigating your material options, you must first look to the design. The following key considerations will develop the criteria for your material:

  • Government regulations
  • Performance
  • Size, shape and weight
  • Cost
  • Manufacturing and assembly (machinability, etc.)
  • Intellectual property
  • Industry standards
  • Reliability

While all the above considerations may not apply to your project, collect data on as many of them as possible. More requirements will help narrow down the final material selection.

Create Material Criteria

All the requirements identified in the previous step will create criteria for your desired material. For example, it will need to support a certain amount of weight, which in turn becomes the load bearing criteria. Any material that cannot support this is immediately eliminated from your possible choices.

Come Up With a Potential Materials List

The first thing you can do with your criteria is rule out any material that doesn’t meet every requirement. You are then left with the materials that can do the job. Create a list, but don’t proceed any further.

Evaluate Potential Materials

You need to right material for the job, but exceeding requirements isn’t necessary. In lean manufacturing, using higher grade materials than necessary is considered overprocessing, one of the eight major wastes.

Some data may not be available, and you may have to go through testing to ensure that it will work for your application. It may even be necessary to create a prototype out of more than one material to be sure.

Make Final Selection

Once you’ve found materials that meet your requirements, choose the one that does the job at the lowest cost. This is not just cost of materials, but also cost of production. Some materials that are designed to be machinable will be harder to form or weld. All this needs to be considered, especially if you are assembling a part that uses multiple manufacturing processes.

Have a Project in Mind?

If you are currently working on a project, or have questions about the right material for your part, upload your file on our quote page. We’ll be happy to answer any questions you have.

Five Reasons to Use a US Manufacturer

APM facility photo

In the early 1970’s GE CEO Jack Welch started moving some operations to overseas factories with lower costs of production. Offshoring continued for decades (and still does), but really began to pick up speed in the 2000s as the internet removed technological barriers and made it easier to deal with foreign operations.

Today, however, a new trend is emerging. As regulations change and labor costs start to increase, many companies are starting to see the advantage in using US manufacturers to complete work formerly done in countries like China.

The following describes five reasons to invest in US manufacturing.

domestic manufacturing infographic

Reason #1: Ease of Communication

Though technology allows you to quickly send an email to check status on your work, getting in touch with overseas workers may not be as easy as you think.

First, there is a significant time difference. When you’re at work wondering what the status of your project is, your point of contact is probably sleeping. Sending an email or calling isn’t likely to get you an immediate response.

Language barriers can sometimes be difficult to navigate as well.

Reason #2: Less Paperwork

Overseas shipping requires lots of complicated paperwork. The documents required depend on the destination country, which in most cases would be the US.

Bills of lading, detailed packing receipts, bureaucratic customs paperwork and special labels are just a few of the headaches you have to prepare yourself for when dealing with international suppliers.

Reason #3: Simpler Logistics

Depending on your purchase, many US-produced goods can easily be sent via a number of methods. Wait times are shorter, and if anything happens, problems are usually resolved much faster. Your overseas shipment could be stuck on a dock in customs for months before it ever makes its way to you.

Reason #4: Advertising Advantages

According to Consumer Reports, 80% of customers prefer to buy good produced domestically. Many will even pay more for them. This allows you to recoup costs by charging a higher price for goods with the Made in the USA label or stamp.

Reason #5: Comparable Costs

Though overseas labor costs are low compared to the United States, they are rising. While they are nowhere near US levels, these rising labor costs combined with increased transportation costs make offshoring less profitable than in the past.