What would be a sufficiently robust way to rethread a hole for a grub which needs to be very tightly fastened?

I have a tilt and slide patio door. The bottom fixtures are secured together by a dowel bar to help prevent the door twisting.

The thread in the hole for a grub which holds the dowel bar in place has sheared off when tightening the grub.

It turns out that the grub needs to be very tightly screwed against the dowel as the door has a tendency to twist at the base as the door tilts (possible installation fault as either frame or door are not quite plumb). The door gets used heavily as this is the only way my dog can get into my back yard from the house.

I am considering a coiled wire thread repair. Does this seem like an appropriate fix? enter image description hereenter image description here


The coiled stainless thread repair kits are the best in my opinion they provide a stronger thread because the larger diameter threads on the outside are stronger and the stainless insert is harder providing a superior hold to softer metals and plastics.

I would suggest using some thread locker to hold the repair kit in place. Thread locker is not a always need but may be helpful to keep the insert in pace

  • Great. It's the inside of an outside door. There is usually a plastic cover over the top but I expect the air to get quite damp and as I want the grub to remain tight I don't want to use a treatment like WD40. Should I be worried about a stainless steel insert rusting? Feb 27 at 21:09
  • I use these on equipment and find the screws rust more than the inserts but that is probably because the high strength stainless probably naturally rust easier.
    – Ed Beal
    Feb 28 at 3:13

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