This is an assembly for potable water filter. I need to unscrew this connection but the weights involved and tools I have are making it a pain. I don’t have a large enough vise to hold everything steady. Any tricks I can use to get this apart with a minimum amount of torque?

it’s 1” NPT.


  • Usually filters unscrew down below a strap wrench is normal, don’t forget to turn the water off and drain the pressure off,
    – Ed Beal
    May 13, 2022 at 19:21
  • @EdBeal the filter is not installed. And this is already removed from the water line. I need to remove the head from the copper. Fitting. May 13, 2022 at 19:48
  • So you need to remove the filter housing from the plumbing then. I was wondering why you show the one side but was not sure if the wedge in the bottom center was part of the issue.
    – Ed Beal
    May 13, 2022 at 21:37

2 Answers 2


You'll need two pipe wrenches, and the floor.

Place one wrench on the floor with its jaws opening upward. Place one side of the joint to be opened (that is, either the flatted section of the copper or the larger round section of the iron pipe) within the open jaws. The wrench handle should rest on the floor.

Hold the other pipe wrench with its jaws opening downward, and place it over the other side of the joint to be opened. Set up the geometry so that when the upper wrench is pressed down, the joint will unscrew. The handle of this wrench should be on the same side of the work (the two plumbing pieces) as the first wrench, but this handle should be raised perhaps 30˚above the horizontal.

Make sure both wrenches fit tightly on the work. Then apply force to the upper wrench to unscrew the two pieces. You can apply force to the wrench with either your hands or feet.

You may have to take several "bites," one after the other, to fully unscrew the pieces. Because you're working downward, you wil be able to apply more force to the wrenches than you could if working with your hands at waist or table level.

  • 1
    I could not for the life of me find a good solid portion of the filter head to attach a wrench to. The filter head’s steel is really round and there’s no flattened hex portion on the filter head anywhere to lock pliers or a wrench on. I tried. A lot. It doesn’t help that I have tendinitis from decades of computer use. I needed something that could hold the filter head stationary no matter the amount of force applied. A bench vise did the trick. May 13, 2022 at 20:53
  • Good work, glad you got it apart. Worth noting that a real pipe wrench will jam very well around even a smooth iron pipe without flats, tho copper is soft enough to probably collapse. May 13, 2022 at 21:13
  • can you link me to a pic of a real pipe wrench? May 13, 2022 at 21:13
  • @RibaldEddie Sure, here's one cropped from Google. May 13, 2022 at 21:17
  • 1
    @DavidSupportsMonica I do have a pipe wrench like that. In fact I have a large one as in the video and a smaller one. However the difference between the video and my situation is that the entire assembly isn’t attached to anything. In the video, the pipe is fixed to the ground so the force applied to the wrenches is entirely transferred to the pipe fittings. If I had been able to brace against the floor as you suggested, it might have worked. But the pipe and filter head just flipped and flopped around under my inexperienced wrenching. May 13, 2022 at 23:33

Answering my own question— when you need to supply a large amount of torque and the shape and weight of the items makes it nearly impossible to apply accurate rotational force without twisting/deforming the soft copper, I find spending a bit of money on a bench vise indispensable.

I ran out to the hardware store and got a vise and then used lag screws to attach it to a heavy table top. Helps to pile a bunch more junk on the table.

This table was actually going to go in my office as a workbench in a couple of weeks and I had been planning to attach a vise to it anyway, so I didn’t feel too bad spending the cash on the vise.

I clamped the metal filter head in the vise and used a 1.25” adjustable wrench to turn the copper pipe. With the heavier filter head locked in place, it required a lot less force to turn the pipe.

Moral of the story— having the right tools and equipment makes a huge difference. this vise

  • 2
    There's never a bad reason to buy new tools ;)
    – brhans
    May 13, 2022 at 20:50

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