Water Cooled TIG Metric Adapter (M16x1.5 to 7/8”)–Homemade

alpha tig

We recently got something of a bargain on a 2014 AHP Alpha TIG 200X. For a few hundred bucks, we couldn’t pass it up. It’s no Miller, but it’s loaded with all the features you would expect from a dedicated AC/DC TIG welder and it performs pretty good. You get what you pay for, and the quality is quite reasonable when you look at it that way, but the problem with these ahem… *imported* machines is finding torches here in the States that fit the M16 x 1.5mm gas outlet. After a lot of head scratching and hair pulling we finally solved the problem with our metal lathe and some parts off of eBay. We apologize for the shortage of pictures but it never occurred to us until we were well into this project that a blog post on the subject might help a lot of people. So we’ll try to explain it the best we can with what we’ve got.

tig adapter partsnipplesTo tacklefemale adapter this problem the way we did, you are going to need a metal lathe. If you don’t have one, find a local machine shop to help you out. You will also need some standard B-size TIG fittings. In the photos to the right you will see a female 5/8 B to NPT adapter, and two 1/4” nipples with B size nuts. The adapter and one of the nipples were turned on the lathe to fit snugly into a custom part that we turned from brass rod. The modified parts are shown on the far right. The custom part was silver brazed to the standard TIG water cooler adapter (the rectangular shaped block – last picture, far right – that comes with most American water cooled TIG torches to bolt to the power lug on the front of the machine). The M16x1.5 nut was then slipped over the modified nipple and the nipple and adapter were then brazed into either end of the custom part which has a hole through the center for gas flow. The idea is that instead of the water cooler adapter bolting to the lug on the front of the machine (there isn’t one on our imported TIG welder and that’s the problem) it will attach to the power/gas outlet by way of the M16x1.5 nut which should spin freely on the nipple.


finished adapterIn the final picture to the right, you can see the finished project. Gas flows out of the front of the machine as normal and through the 5/8 B gas fitting to the gas hose on the torch. Coolant is delivered to the torch head from the water cooler and returns down the integrated power cable to the 7/8 to 5/8 adapter. Another 1/4” nipple is threaded into the 5/8” end of the adapter and some 1/4” automotive vacuum hose returns the coolant to the cooler. You will need three of the 1/4” nipples in all, with nuts, because one final nipple and nut is used on the return fitting of the water cooler.

On a final note, our brazing job looks like something out of a 17th Century shipwreck but it works. In the end we’re not sure if silver brazing is really necessary and it was hard to accomplish without melting the part. That was because it was hard to hold the M16x1.5 nut (which must be able to spin freely on the finished product) and sneak the silver braze in behind it to braze the nipple into the custom fitting. The temperatures required for silver brazing are high enough that an ordinary propane torch won’t do the trick. In hindsight, a good electrical solder would probably do the trick provided there is good fitment of the parts. Good luck and sorry again for the lack of more pictures. The blog post was kind of an after thought but we hope it helps!