I just bought a shower head from Amazon (Chinese seller I think). As soon as I received it I removed the old one and tried fitting it in. But it cannot be screwed in. The diameter seem identical to the old one with my bare eyes. But the old one screws in easily and this one stops after one turn. I tried cleaning the threads with a toothpick, adding some WD40 and it does not get any easier. Do I need a connector? How universal are the connector widths?

I have added pictures.

ps: It is not easy to force as the disk part can spin 360 degrees around the connector, hence I have preferred not to force for now.

Link to the item I purchased if it helps: https://www.amazon.co.uk/gp/product/B07SSZ9RH7/

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  • Carefully measure the thread pitch (say how many fit in 1/2"). Do they match?
    – isherwood
    Commented Mar 12, 2020 at 13:14
  • @isherwood will do and let you know Commented Mar 12, 2020 at 13:25

2 Answers 2


Your photo is not all that helpful but it appears that you are attempting to screw the new unit into a part off of the old one. You should remove that part that is sticking out from the disk and get to the standard plumbing stub that is coming out of the wall. That is where your new shower head should attach.

I have no idea what that circular plate is doing. Is it a part of the new one or the old one? Some better photos of what you received from Amazon might help here.

  • The plate is the new shower head, I believe. The male threads seem to be on a standard shower nipple. I assume that it's a matter of dissimilar threads due to foreign standards.
    – isherwood
    Commented Mar 12, 2020 at 13:14
  • I will add better pictures asap. The part I am trying to screw is not from the old unit (shower head). It is the shower mount from the wall. Inside the Amazon box was the new unit (the disk on the pictures), it is one piece and an O-ring, no manual or anything else. Commented Mar 12, 2020 at 13:14
  • @isherwood It does look like the size is the same but the threads are larger on wall mount (UK standard I would guess) that on the head (Chinese make). Is thta plausible? If yes, anything I can do? Commented Mar 12, 2020 at 13:24
  • I would agree with @jhw20 , normally in the US showers are 1/2” NPT and that fitting looks “funny”.
    – Ed Beal
    Commented Mar 12, 2020 at 14:01

If you look at the photos from Amazon it shows a G 1/2 thread on the shower head. Those are straight threads not tapered which would explain the rubber washer. I'm going to guess the shower arm has tapered threads. How does the old head fit, does it gradually get tighter and tighter or does it thread evenly until it compresses a rubber washer.

  • I screwed it twice to be sure, and the feeling is definitely that it gets tighter and tighter. I read a bit about the 'mating' of tapered threads and sounds like you are right. Can you advise and adapter that could solve the issue here? Commented Mar 14, 2020 at 18:24
  • I have found this tiny.cc/if4alz Could that do? Commented Mar 14, 2020 at 18:32
  • In the description it indicates "BSPT ( Taper) European Male Thread to NPT Straight American Female Thread" You're in the UK, my guess is the arm is British thread not American although if it's new you can check from where you purchased. They are both 14 threads per inch but the angle of the thread is different. It will probably screw together but it might leak, with thread tape it might not. Commented Mar 15, 2020 at 12:29

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