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Single O Flute CNC Bits: Differences, Similarities, & Uses

Single O Flute CNC Bits: Differences, Similarities, & Uses

A recent question was asked by one of my customers “These two bits look the same, can I use them interchangeably?”. The customer was referring to a single o flute CNC bit for plastics and a single o flute CNC bit for aluminum and ACM. Even though both of these bits could cut the opposing material they are made for, the answer is “No!”.

Here’s why.

Single O flute CNC bits may look similar but they are created differently to optimally cut a specific material. Four main factors distinguish these apart from one another and are critical to the edge finish and tool life. If you’re looking for optimal edge finish, use the single o flute meant for that specific material.

  1. Helix Angle
  2. Cutting Geometry
  3. Polished Flutes
  4. Cutting Edge Sharpness

Before diving into each one of these, I will note that upcut bits are going to provide the best quality, effective chip evacuation, and remove more heat. A downcut bit is used more often when additional part hold-down is necessary. A downcut bit can cause rewelding of parts which is where a slight groove in the spoilboard can be helpful for chips to fall free.

Single O Flute CNC Bits
(Acrylic/Wood/Assorted Plastics)

1. Helix Angle

The helix angle of a tool is measured by the angle formed between the centerline of the tool and a straight line tangent along the cutting edge. The helix angle on a single o flute for plastics is going to be less than one made for aluminum. A “multi-purpose bit” is going to be somewhere in the middle. Please note that a multi-purpose bit will not cut plastics as well as a bit created to cut plastics nor cut aluminum as well as one created for aluminum. These are common for users operating a collet spindle in which they use one bit in order to save time. If you have tool holders and automatic tool changing, there is no need for an expensive bit that provides poor quality.

2. Cutting Geometry

The research and testing behind CNC tool cutting geometry was very important in deciding how to achieve high quality edge finishes. This is research that continuously improves which is why new tools flood the market every year. The way a CNC bit cuts into a material and then releases the material chip is important. Too large of flutes could tear material instead of cutting it. Too many flutes could cause an increase of heat. There are many geometry factors that require complete optimization for a tool to work properly. When it comes to single o flute CNC bits, this is exactly the case. The geometry of each has been optimized for recommended materials.

Single O Flute CNC Bits (Aluminum/ACM/Wood)

3. Polished Flutes

Polished flutes assist in providing a clean or smooth finish, especially when it comes to a material like Acrylic. The goal, when cutting acrylic, is often to achieve the best and most clear or see-through edge. A polished flute is best suitable to assist in this process because there are fewer tool edges that can cause inconsistencies. On the other hand, a polished flute is not necessary for cutting a material like aluminum. Aluminum is tough enough and doesn’t show tool marks as frequently.

4. Cutting Edge Sharpness

You may think that the goal for tooling would be to sharpen the cutting edge as sharp as it can get. The problem with that is that the edge will then become brittle and/or inconsistent which in turn can cause a shorter tool life and/or poor edge quality. Each single o flute has a sharpness that is best suitable for the material that is recommended.

All in all, single o flute CNC bits made to cut plastic should be used on plastic and the ones meant to cut aluminum/ACM should be used on aluminum/ACM. Again, I personally don’t recommend multi-purpose bits unless someone has a collet spindle, low quality standards, and time constraints. So, do not use single o flute CNC bits interchangeably unless you don’t care about edge quality and tool life. Your product will not look as good as it should and your bits won’t last as long as they could.

Find CNC Single O Flute Plastic Cutting Bits: HERE

Find CNC Single O Flute Aluminum Cutting Bits: HERE


When orders are placed, they will be double checked to ensure no errors were made and customer follow up will take place during the same day (unless an order is made after hours). If products are available, which most of them are, they will be shipped out the same day. If they are not available, a lead time will be provided. Feel free to reach out for any assistance with our website or anything else regarding CNC routing and knife cutting.

CNC Tooling Shop, a division of Specialty Machinery Inc.

Email: tooling@cnctoolingshop.com

Hours: 8:00 AM to 5:00 PM (EST)

Phone: (616) 502-7277


Greg Smolka

Greg Smolka (Author)

CNC Tooling & Application Manager

Here to help with tooling recommendations (bits, knives, collets, tool holders, maintenance kits, torque stations, etc.) and cutting recommendations (feeds/speeds, tips/tricks, # of passes, etc.).

Contact Infogreg@cnctoolingshop.com

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CNC Tool Holder & Collet Maintenance

CNC Tool Holder And Collet Maintenance

Taking proper care of your collets and tool holders will increase the life of your collets, tool holders, CNC bits, and spindle. Not only will it increase tooling life but it will also improve cut quality. I like to think of tooling maintenance like changing the oil in a car. Sure, the car will run without ever changing the oil. However, there is a risk of blowing a gasket and warping other parts of the engine until it ultimately fails. The same goes for a CNC router. The more time a spindle is in use while being out of balance, the more of a chance it risks failing. For those of you who want to get the best out of your CNC machine investment, let’s discuss tooling maintenance.

Did you know that both the collet and tool holder have a life cycle.? Collets should be replaced every two to three months. They can even be damaged without any visible signs. A very common problem is metal fatigue which can be caused from overtightening. Be sure to use a torque wrench and tightening stand to escape this problem. Regardless, over time the gripping power will reduce with use and heat. This is why it’s very important to replace these in a timely manner. Tool holders, on the other hand, have a much longer life cycle. They should be replaced every one to two years. Like the collets, these will break down over time. Fretting and bronzing are common as tool holders get older. This is all of course dependent on the use of these tools. If a collet and tool holder is only used for an hour a week, then yes it may last longer. However, that’s if the collet is removed from the tool holder and both are cleaned and kept in a dust-free area. I have a habit of cleaning my tools after every use then putting them back in the original packaging. Not every operator has this luxury because of time constraints. So, for most of you, replacing them in a timely manner, even if they aren’t used as often, is the best option.

Besides replacing these parts when needed, It’s also important to take care of them while in use. Proper cleaning is essential for reaching full life cycles of each and achieving best cutting results. Here are the cleaning steps that should be done on a regular basis. This should be done every time a tool is changed or replaced from a collet/tool-holder.

Step 1

Use air to blow off as much from the tool holder and collet as possible. Blow off any debris, dust, and material chips. Build up often happens within the gaps of the collet. Not blowing these out could cause the collet from not being able to tighten properly.

Step 2

Use a clothe rag or paper towel to wipe off any leftover dust or material chips that are stuck to the collet and tool holder. Sometimes using a piece of paper, folded up a couple times, will help get hard to reach chips lodged in the collet gaps.

Step 3

Use the Spindle Wiper Kit to clean out the spindle opening, tool holder opening and center of collet. These are made to clean the hard to reach areas. This is especially important in the spindle and collet opening because they are nearly impossible to clean without this kit.

Step 4

Use the Nu-Tool Cleaning Protectant & Rust/Debris Remover to thoroughly clean the collet and tool holder. The rust/debris remover is only needed when rust or heavy debris are present on your tooling. For the most part, the protectant is the go-to product. This should be used to aid in cleaning every time a CNC bit is replaced. At the VERY minimum, these should be cleaned weekly to get the most out of your tooling.

If these steps are regularly taken, you will get the most out of your collets and tool holders. Your cut quality will be the best that it can be and your spindle will be in balance which in turn will allow it to last longer. Again, treating your machine like you would a car by giving it regular maintenance will help you get the best out of your Multicam CNC machine investment.

Greg Smolka (Author)

CNC Tooling & Application Manager

Here to help with tooling recommendations (bits, knives, collets, tool holders, maintenance kits, torque stations, etc.) and cutting recommendations (feeds/speeds, tips/tricks, # of passes, etc.).

Contact Infogreg@cnctoolingshop.com