Just as a flaring tool is used to make a flare connection, a swaging tool is used to make a permanent brazed connection. Swaging the end of your tubing is similar to flaring in that your goal is to gradually widen the end of your tube. However, swaging eliminates the use and expense of fittings, as well as the opportunity for leaks. Swaging allows you to increase the inside diameter of the tubing for a short length so you can slip one tube inside the other before brazing.
There are a number of different styles and sizes of swaging tools available, from the traditional punch-type to feed screw to tube expander. Many flaring kits also come with swaging bits to turn your flaring bar into a swaging bar. Get to know your options before settling on a personal favorite.
First, let’s look at the traditional punch-type swager. As the name suggests, this tool is designed to punch the end of your tubing.
- Insert the lead end of the punch into the tubing. Make sure the tool is aligned perfectly straight with the tubing. A common mistake is to drive this into the tube at an angle.
- While gripping the tubing tightly, use a hammer to strike the punch, driving the swager into the end until you reach the stop and have achieved the form you’re looking for.
Feed Screw Swager
Another swaging tool option is the feed screw swager.
- To begin, outfit the feed screw with the proper size swage bit and then retract the feed screw out as far as possible.
- Check the tube grips on the bar. The grips can get filled with copper and cleaning the copper out will ensure that the tube doesn’t slip.
- Insert the tubing into the bar, extending it through the bar farther than you would for a flare, as a swage requires more depth than a flare.
- Tighten the bar around the tubing, leaving just enough space for the tubing to slide up and down between the bars.
- Position the yoke and swage tip on the bar over the tube.
- Slide the tube up to the bottom of the swage tip. This is the position the bars need to be in before the butterfly nuts are tightened.
- Remove the yoke to prevent injury and then tighten the bar starting with the butterfly nut closest to the tube.
- Tighten the second nut. Tightening the butterfly nuts for a swage is a little more critical due to the amount of force required to forge a swage. So, after tightening down the second nut, it might be helpful to back it off a bit and go back to the first nut and tighten it a bit more. Return back to the second nut again and tighten it down.
- If the tube slides during the swaging process, repeat this back and forth tightening to improve the grip on the tubing. But remember; always tighten down the butterfly nut closest to the tubing first.
- It’s also a good idea at this point to use just a tiny amount of lubricant between the swage bit and your tubing. Not enough to contaminate your braze joint, just enough to offer a little lubrication, especially if you’ve performed a lot of swages with your bit.
- The only thing left to do is feed the swaging bit into your tubing. During this part of the procedure if you notice the tube is slipping in the bar, back out the bit and retighten your bar. Allowing your tubing to slip around will ultimately render your bar useless.
- While your bit is entering your tubing, note whether or not you have extended the tube out past the bar enough. If your tube is set at the proper height, your swage won’t bottom out on the bar.
Tubing Expander Kit
The long handles on the Tubing Expander Tool offer great leverage for expanding soft copper tubing from 3/8” to 1-5/8” outside diameter. In addition, this tool is excellent for re-rounding deformed tubes and fitting ends.
- Outfit the tool with the proper size expander head for your tubing.
- Insert the tubing over the expander bit.
- Slowly actuate the handles and carefully release the tubing. It’s important to use slow steady movement when operating this tool. Failure to carefully release the tubing may cause personal injury or damage the tool.
- If you’re expanding smaller diameter tubing such as 3/8”, it’s a good idea to expand the tubing half way, retract the bit, rotate your tubing a quarter turn and then actuate the handles once again.
This tool creates perfect swages on soft copper easily and quickly every time. Using it properly and lightly lubricating it from time to time will give you years of great performance.