Kodiak Cutting Tools® Speeds and Feeds Blog

Cutting Tool Talk, Tips and News for Machinist, Metalworkers and Fabricators of All Kinds

End Mills for machining plastics

A customer was looking for an end mil to try on plastics. Plastics come is a wide variety of compositions and hardness, therefore a lot depends on the type of plastic being machined. Here is our advice to get started:


      All of our end mills are designed primarily for metals, but many people use them on plastics, composites and hardwoods as well. I would start with the basic four flute end mills. If you have trouble with chip clearance/chip evacuation, you might have to look at a 2 flute, however, you will get a better finish with the four flute. We have some customers that have used the end mills for aluminum in harder plastics. These tools for aluminum have a higher helix angle and more room between the flutes for chip evacuation. Because the core does not have to be as large and strong as for other metals, we can grind these deeper for better chip removal. The aluminum cutting are a high-performance tool that cost a lot more than the regular end mills though, so you have to take that into account.


         Although you may see some benefit from a coating, I don't think it would justify the expense, so I would stick with the uncoated tools. Most people cutting plastic seem to be using uncoated tools. I don't think you see much benefit from the coatings until you reach higher temperatures, like 900-2200 degrees F.


         So here are some links to some basic ones to consider. Other variables are length, ball end and corner radius, in addition to the regular length  square end end mills that I have linked to here.


         Just let me know if we can be of any further assistance.









question about 2 flute vs. 4 flute carbide end mill for aluminum

A customer was trying to decide whether to use a 2-flute or 4-flute carbide end mill for his job on aluminum. One important question before spending the extra money for a high-performance tool, is how many parts are you making?

 I think one you might look at is our part number 136475. This is 1/4" x 4" long with a 1" length of cut. The number of flutes is a trade-off between better finish and better chip evacuation. Sometimes with softer grades of aluminum the flutes could get clogged up, but as long as that is not an issue for you a 4 flute will give you a better finish and do more work per rotation of the tool. I think a lot of people are using this tool for doing a similar application. There is also a popular one with the gunsmiths that is specifically for aluminum. The part number is 150104 (150027 for uncoated). This is a high-performance tool that is capable of doing long production runs and much high speeds & feeds than the standard tool, but if you are not doing a large quantity it would probably be more than you need. The high performance ones have 3 flutes, a deeper clearance between the flutes for better chip evacuation and an optional ZrN coating specifically for aluminum and other non-ferrous metals. The high-performance also has a 45 degree helix instead of the standard 30 degree. This provides a better finish due to a shearing action of the flutes and also helps get the chips up and out. The main reason carbide end mills fail is when the re-cut a chip from the previous machining, so the chip evacuation is important, but if you are doing a smaller quantity you can try to use air of fluids to keep the cutting area clear from chips.


Using micro end mills in 92% Cu 8%Ni

We recently had a question about milling fine patterns in 92% copper, 8% nickel coin. The user would like to mill through to the other side of the coin and create a pattern with finely detailed edges.


     Yes, this definitely can be done. You generally are able to mill at a max of 1Xs the diameter of the tool. So it is a trade-off between the diameter you will need for the finer details of your design and the number of passes you will need to make to go through the material. The micro end mills are available with lengths of cut that are 1.5Xs and 3Xs the diameter. The type of mill you use would depend on the diameter you choose and what operation. The more flute the better your finish will be and the more cutting action per rotation of the tool you will get, however if the material is mostly copper, that may clog the flutes and require a 2 flute for the roughing portion of the operation. Ideally, if you can find a diameter that will allow you to do the whole pattern without a tool change, that would be nice, however you may have better results doing it in two steps. Maybe use a larger 2-flute tool to allow a complete cut-through to the other side, and then rough out the bulk of the pattern. Then you could follow-up with a smaller diameter 4 flute tool that will allow you to finish the detail. If you do the whole thing with a very small tool, it may take awhile. You want to keep the tool/flutes as short as possible to improve rigidity, however you need some room for chip evacuation. As with everything in the milling process, it is a trade-off between a few different variables.


      As far as the speeds and feeds, we have all of that information available at the links below. An easy way to do it is to plug the values from the chart into the online calculator. One variable you won't know is the limitations of the spindle speed of the machine you decide to purchase. Which brings me to my next point.


       We don't really have a recommendation for a particular machine, but I know there is a huge range of options out there. I believe you will want to run these smaller tools run at higher RPMs, so that might be a factor. If you plug the variables from the speed and feed chart into the calculator, that will fill in a spindle speed you could use as a reference. One of the brands that has been around for awhile for smaller work like this is Sherline. http://www.sherline.com/


      Please see the point-by-point answers per your list below. Also, here is the link to the speed and feed chart and calculator. Just let me know how else we can help you move forward with your project.

                               Thank you for the inquiry!



Speeds & Feeds: http://www.kodiakcuttingtools.com/CarbideEndMillSpeedsAndFeeds.asp

Online Milling Speed & Feed Calculator: http://www.kodiakcuttingtools.com/calculators.asp

End Mills for Aluminum

A customer recently asked about what style of end mill to use for his aluminum application. Here are some general guidelines:

It is a trade-off between chip-evacuation and finish. A lot of times with aluminum the long stringy chips can clog up the flutes. This often leads to re-cutting the chip, which is the main cause of tool failure with end mills. So the chip-evacuation is important, but depending on the grade of aluminum and the cut, you could use a 4 flute. Generally, the less flutes = better chip-evacuation AND more flute = better finish/more work per rotation of tool. The aluminum cutting tools you have on this order have a higher helix angle (45 degree instead of 30 degree) which creates a better finish through more of a shearing action as the end mill cuts. The aluminum style also has deeper spaces between the flutes for better chip-evacuation. The core-diameter of the tool does not need to be as large when cutting aluminum, so this deeper flute design works well. These are high performance tools designed for maximum material removal rates and should be run at the speeds and feeds for the high performance tools on our website.

End Mill Selection

A customer recently asked what end mill to run for a full-slotting application in stainless steel and for some general recommendations about high speed vs. carbide and how many flutes to use. Listen in to our reply:

The 2 flute is usually used when you have a material that produces long stringy chips that get clogged in the flutes. That is usually referred to as 'chip evacuation'. The 2 flute has more room to clear the chips, however it does not leave as good of a finish as the 4 flute. So you can get from 2 to 6 flutes, and as you go up in flutes you get better finish and more work, or cutting action, per rotation of the tool. For example, if you were taking a chip load of .001" per tooth, you would be removing only .002" per rotation of the tool with the 2 flute, as opposed to .004" per revolution with the 4 flute.  The tool is also more engaged with the workpiece when you have more flutes, so you have less chance of chatter and poor surface finish. For tools that produce stringy, chips like aluminum, brass and other mostly non-ferrous materials we offer 2 and 3 flute tools that have a higher degree of helix than the standard 30 degree. These aluminum tools are available in 2 or 3 flute and have a 45 degree helix which creates a shearing action and gives a better finish because of that. We have some high performance tools for stainless that also have a higher helix.

     We would definitely recommend carbide as long and you have a good rigid toolholding and workholding setup. These days high speed steel is usually used on older machines that cannot generate the spindle speed or are not rigid enough for carbide. Carbide used to be more expensive than high speed steel, as usage and volume has shifted to carbide, they have become the less expensive in many cases than the high speed counterparts.  Especially on the smaller diameter tools.

    So depending on the amount you have to do and the capability of you machine, you would have to decide to run a high performance tool or the standard end mill. It also depends on the depth of your slot. For the standard tools you can do full slotting at 1x's the diameter on the tool. If you go with the VI-Pro high performance end mill, you can slot at 2x's the diameter. So with most grades of stainless you should not have a chip evacuation problem, so you should use 4 or more flutes. However, a common reason for end mill failure is caused by 're-cutting' a chip. So it is important to have some means of removing the chips from the workpiece as you go to avoid any re-cutting. The carbide is capable of doing a lot of work, but it is also brittle to some degree. So the chips can get work-hardened from the initial cutting and then if the tool re-cuts a chip it can cause the tool to chip. The only chips you want are from the workpiece. The rule of thumb is to use as short of a flute length as possible, which produces the most rigid setup. However you want to make sure you have enough flute to get the chips up and out of there. Especially in a full-slotting application. We would recommend the ALTiN coating for stainless. Below we have listed the different series of tools that you might consider and a link the reference documents.

These are all stub length. Go for a longer tool if you need one, but start here - these are also the least expensive option.


standard 4 flute stub length for max 1xs diameter slotting per pass http://www.kodiakcuttingtools.com/viewproducts/carbide-end-mills-4-flute-single-end-stub-altin-coated/

standard end mill speeds, feeds and recommendations


you can plug the figures from the above chart into this milling calculator:


Best for higher production and max 2xs diameter slotting per pass:

VI-Pro variable index high performance end mill (less chatter with high speeds and feeds)http://www.kodiakcuttingtools.com/viewproducts/carbide-end-mills-vi-pro-4-flute-stub-altin-coated/

Vi-Pro speeds and feeds


Another option for better chip removal:

3 flute high performance with 45 degree helix (this would give you more chip clearance if that is an issue)


high performance speeds and feeds






1-2 Day Shipping Program Explained

Many ask; "how do we do it?"

We have been offering our 1-2 days shipping program for at least 5 years, and let me tell you, customers love it! The price has been the same for the past 5 years, which is $8.50 or free for orders over $250. We often have people on the west coast ask us how we do it. Especially with fuel surcharges and additional residential delivery fees, it can get expensive quick. Due to our high volume of shipping, we have made special arrangements with our carriers that allow us to serve the entire continental USA with 1-2 day shipping.

This is how it works; if you are already in an area that will receive your package in the 1-2 day timeframe via standard delivery service, your order will be shipped via standard shipping. In areas that are beyond that, where delivery would normally 3, 4 or 5 days, your order gets automatically upgraded to a premium 2-day service. To make things even more convenient, we offer same day shipping of in stock products until 5pm eastern time. We ship Monday-Friday, excluding holidays.

Thread Forming Taps - Stronger Threads and No Chips

Why should I use thread forming taps?

Thread forming taps produce threads by displacing the material rather than cutting and removing the material to form the thread. This essentially cold-forms the thread, producing a strong thread. Another benefit of thread forming taps is that they do not produce chips like a cutting tap would. Forming taps are known to also provide extended tool life due to the fact that there is no cutting action, there are not sharp edges to dull. They also stronger taps by nature because there are no flutes. Larger sizes of forming taps have what are called lube-grooves, to allow some clearance for lubricant and enhance the performance of the taps. These lobes are visibly if you look at the tip of the tap. You will notice that the forming rings on the tap are not perfectly round, but have lobes.

What materials should I use them on?

Any material that produces a stringy chip is a good candidate for thread forming. They are most commonly used on aluminum, brass and other non-ferrous metals, however the can be used on certain grades of steel and stainless steel. Most ductile materials producing stringy chips are great for forming.

How should I use thread forming (roll) taps? 

Thread forming taps require different application parameters than standard cutting taps. Here is a link to our recommended speeds, feeds and hole sizes for your thread forming operation.


End Mills - High Speed Steel vs Carbide

End Mill Selection has Evolved and Materials Have Improved

   It used to be that carbide end mills were much less prevalent than they are today. Some time ago high speed steel and cobalt tools were much more widely used and less expensive. As time has gone on carbide tools have become more competitively priced and have become the preferred end mill by many machinists. The advantages of carbide endmills are numerous. They are much more rigid and produce tighter tolerances for machining precision parts. Carbide is also much more wear resistant. However, although carbide is tough and wear resistant, it can also be brittle. For this reason many older machine setups that are not as rigid prefer to still run high speed steel and cobalt tools for the additional forgiveness they provide.

   At Kodiak cutting tools our solid carbide endmills are made from ultra-micrograin carbide. This means that the structure of the molecules in the carbide are smaller and more consistent than and lesser grades of carbide. This grain structure allows the carbide to wear in a more even pattern and provide better tool life. Other tools, such as carbide burs which are not as precise, may be manufactured with a carbide that has a larger grain size. Some inferior manufacturers of carbide end mills use a lesser grade carbide with a larger grain structure, which makes the tools less expensive, but it also makes them less durable and more difficult to grind to exacting tolerances. That is why, although our tools might cost slightly more, in the long run better quality will save you money and increase your productivity through longer tool life and precision performance.

Hand Taps - Not Just for Hand Applications

Did you know that all of are taps are designed to be used under power?

Sometimes if is a little confusing, because standard straight flute threading taps are often referred to as hand taps, that they are also used in machine applications. There are accessories available for using these taps by hand, such as tap handles, tap wrenches and tapping alignment tools, but the standard straight flute taps can also be use for smaller run machine tapping. All of our standard straight flute taps are made from premium grade M-2 high speed steel material, to provide maximum tool life. For additional tool life you can also consider a coating such as TiN or a treatment such as Steam Oxide or Nitride & Steam Oxide.

Take a look at our tap selection here: http://www.kodiakcuttingtools.com/viewcategory/taps

Speeds and Feeds for Double-Lead Taps

How do you run a double-lead tap?

As you probably already know, a double-lead tap traverses twice the distance per rotation as a standard tap would. The question of how to run them comes up from time to time, so we thought this would be a good entry for the technical section of our speeds and feeds blog.

The answer is that do not change the RPM that you are running at, but you will need to double the feed rate in order to properly form the double-lead thread tap.