Wall mounted mixer tap falls off - grub screw not gripping the cartridge

[zeuslawyer]

Hi Folks I have a kitchen and shower tap that have the same mixer assembly, though they have different designs

The handles slide right off the cartridge.  I've tried putting in a new grub screw but it still doesnt "grip" the plastic of the cartridge.

[UPDATE] it appears that the screw hole on the tap handle has been stripped by the plumber who repaired it some years ago. The hole is either a touch too large now or the screw threads dont hold hold and standard sized grub screws from Bunnings are able to turn endlessly without "gripping". Also the grub screw eventually just goes right through the hole.  

Any ideas what I can do to fix this?

[EricL]

Hello @zeuslawyer 

Welcome to the Bunnings Workshop community. It's fantastic to have you join us, and thank you for sharing your question about your wall mixer tap.

I'm sorry to hear that your tap handle fixing has been damaged. I suggest trying the following methods to fix it. I propose using Loctite 222 10ml Threadlocker Adhesive to fix the grub screw in place. 

However, if the grub screw keeps slipping from the threaded body, I suggest replacing the grub screw with a Pinnacle M4 x 10mm Zinc Plated Round Head Bolts and Nuts. There is a possibility that it might be a tight fit, the purpose of using a larger screw is to create a new threaded path for the screw to anchor onto.  

Another option is to wrap the grub screw in Kinetic 12mm x 10m White Standard Thread Seal. This should give the grub screw extra width so that it latches on to the threaded sides of the hole.

Let me call on our experienced members @TedBear and @JoeAzza for their recommendations.

If you have any other questions we can help with, please let us know.

Eric

[JoeAzza]

@zeuslawyer  Suggest re tap hole to next size thread and grub screw. You will need to a threading tap and grub screw , next size up to your existing grub screw.

[zeuslawyer]

Thanks @JoeAzza  and @EricL ! Really appreciate this!

Questions:

1/ @EricL  - wont the threadlocker adhesive effectively lock the grub screw which means the handle can never be removed/repaired etc? that doesnt seem like a desirable outcome?

2/. @JoeAzza / @EricL  i'm new to this so any chance you guys could link me to what a "threading tap" is? and how do i establish the exact size? i think its a M5 but cant be sure.  I dont even know what retapping is, but perhaps the tool will have instructions

Thank you so much!

[JoeAzza]

@zeuslawyer here is a YouTube video on how to retro a larger thread on an existing threaded hole that has a stripped thread, you will need a next sub zero tap and a tap wrench , they should be available from Bunnings or a local tool shop

if it is a 5 mm screw you will need a 6mm intermediate tap.

https://youtu.be/SXxp9Hjyz40

[EricL]

Hi @zeuslawyer 

The Loctite 222 10ml Threadlocker Adhesive does lock the grub screw in place but is not a permanent fixture. You can still dismantle it using regular tools. If, however, you were to use the Pinnacle 10ml Red Thread Locker this adhesive thread locker would permanently bind the threads of the steel together.

If you need further assistance, please let us know.

Eric

[zeuslawyer]

Thanks all @EricL and @JoeAzza !! Most helpful.  I will try these out.  really appreciate the help guys.