How to Use a Tube Notcher

In the automotive world, a tube notcher, or tubing notcher, is a tool that is designed to create “fishmouth” notches in metal tubes. Our own Eastwood Tubing Notcher can create notches up to two inches in diameter that range in angles from 90 degrees to 150 degrees using a hand drill or drill press with a 1/2 inch or larger chuck. Below, we take a look at how to properly use this tubing notcher.

Important Safety and Operation Tips

Since this tool uses saw bits with very sharp teeth that are designed to cut through metal, it is imperative that you use proper eye protection whenever you use one. When metal is cut into “fishmouth” notches, the edges are also extremely sharp, so always wear a pair of heavy gloves when operating the machine. Keep in mind that prior to welding any notched tube to another part, you will have to grind or file those edges down. Also, always be sure to keep any loose clothing, jewelry or hair away from any moving part.

The tubing notcher is specifically designed for making “fishmouth” notches in metal tubing. If the metal is a soft metal, like copper or aluminum, the tube will be easier to cut and require less effort to achieve good results compared to metals like carbon and stainless steel. Whenever you are operating a tube notcher, it is important to keep the saw teeth lubricated with cutting oil and keep the feed to a slow speed. Always make sure that the arbor shaft is clean and clear of metal chips, dirt and other debris. After each usage of the tube notcher, clean the tool of any excess oil or metal pieces, handling them with care. Also, replace the lock pin to keep the arbor shaft in place, and remove the entire saw for safety. With that information out of the way, let’s learn how to make tube notches.

Using the Tube Notcher

First things first, if you are mounting the tube notcher onto a drill press, make sure that the base of the unit is square to the main body, the foot is securely attached to the table, and the shaft is centered directly underneath the chuck. Place the tri-flat section of the shaft in the chuck, and make sure that each chuck point is in contact with each shaft flat. Check the up and down motion of the drill press spindle, and make sure there is no binding or friction in the tubing notcher before you turn on the drill press. If you are using the tubing notcher for benchtop and hand drill use, make sure the base of the tool is securely mounted onto a stable benchtop and clamped tightly in a large mounted vice.

Once you have set up your tube notcher, determine your angle of the “fishmouth” notch to be cut into metal tubing. Loosen the three lock bolts only slightly, adjust the tubing clamp using the gauge to the determined angle, and securely tighten the lock bolts back again. Now, place your tubing into the “V” notch using the curved part of the clamping hoop, and tighten it down with the “T” handle. Keep in mind that you should always make sure that the “fishmouth” is at the end of the pre-cut section of tubing, not the middle. Mounted on the main body of the machine is the arbor carrier. The arbor carrier allows you to provide adjustment for the location of the hole saw, based on the angle of the tubing clamp. Always remember to keep the saw cutting edge as close to the work as you can to increase cutting accuracy and decrease excess vibration.

Before you cut your tubing, make sure that the locking pin is removed and that the saw is tightened securely to the arbor carrier. If you are using a drill press, set the speed between 250 and 500 RPM, and for hand drilling, just be sure to keep the variable speed low. Slower is better when cutting non-steel tubes this way to avoid excess heat buildup and minimal vibration. Also, make sure that you are using enough cutting oil on the metal saw teeth, feeding the saw slowly. Make a couple practice cuts on scrap tubing first to get the hang of the tool, then you’ll be ready to begin cutting your own precision “fishmouth” notches.

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