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My fitting nut has broken off in the end of my LC column. What to do?

5 Sep 2019

If excessive force is applied at an angle to a fitting or column connector, the ferrule could become stuck in the column end fitting. Likewise, a PEEK connector, column nut or plug can also break and leave part of it in the end fitting. Stainless steel nuts are much harder to break, although a stainless steel ferrule could become stuck if severely over-tightened or cross-threaded.

Whether PEEK or stainless steel, if it is a column nut or PEEK connector that is stuck in the column and there is significant portion still sticking out from the column, I would try first to find a tool to grab hold of this part of the nut to see if it can be loosened by unscrewing. You may be able to use a pair of needle nose pliers or pointy-ended vice grips for this. If the nut does not move after a little effort, this is probably not going to work, since the pieces will likely break further. I would move on to try something else.

If it is a PEEK ferrule that is stuck or a nut/connector that has broken off and is still stuck, try using our PEEK fitting extractor tool, catalog # 25325.

extractor tool

Below is a complete listing of all of the PEEK connectors, ferrules and similar products which Restek sells that you may be able to remove using the tool above, catalog #25325.  (Note: this is not a guarantee, but our best suggestion. Also, please note that these are all for 10-32, 1/16” fitting size.) Most of our connectors are a design that incorporates a nut and ferrule into one piece. We offer several varieties of these connectors now and also something similar in PPS (polyphenylene sulfide) material. The list also includes a PEEK coupler and a PEEK ferrule for a Secure-fit fitting.

Universal PEEK connectors and plug- 25015. 25016, 27710, 27711

a few blue plastic pieces a group of white items a pair of black items


PEEK Hex-head Fittings- 27712

hex-head fitting


PPS Hex-Head Fittings- 27714

hex-head fittings


PEEK Column Couplers- 27724, 27725, 27726

column coupler


1/16” (PEEK) Ferrules for Secure-Fit- 20568


Please note that for the Secure-Fit fittings, the tool can only be used to remove the PEEK ferrule shown above. It cannot be used for the metal ferrule that goes with this design.

If you are using a fitting composed of a PEEK nut and a PEEK ferrule that are separate pieces, you can use the same tool for this also. (Restek does not sell this type of fitting, but the tool can still be used.)  Usually it is less likely for the nut to break in these cases, and the tool would mostly be used to remove the ferrule. If the PEEK nut does break and is stuck also, I would suggest trying the tool to remove it.

Instructions for PEEK fitting extractor tool, catalog # 25325 are shown below. Please note that one should never apply excessive force to the tool, as it can break.

Instructions for Use:

  • Drill an opening approximately 1/4" deep in the center of the PEEK fitting by turning the narrow drill bit in a clockwise direction. To prevent damage to the head of the column, do not drill deeper than 1/4".
  • Once the opening in the fitting has been created, remove the drill bit.
  • Insert the extraction tool into the opening. The extraction tool has a tapered bit and reverse threading.
  • Turn the extraction tool in a counterclockwise direction, the normal direction used when removing a PEEK fitting. The tool should grab the PEEK fitting and begin to unscrew the fitting from the column


If you are not able to remove the nut or plug by using the tool, we recommend replacing the column. Please note that we do not recommend disassembling a column yourself to attempt another means of fitting removal.  Removing the column end fitting may disturb the packed bed which will likely reduce column performance.

Also, if a stainless steel ferrule is stuck in the column end fitting, it is very unlikely that this can be removed successfully without damaging the column end fitting.  In this case, the best solution is to replace the column. Again, Restek does not recommend disassembling the column and cannot guarantee performance, accept the return of, or replace a column that has been disassembled once it leaves our facility.

I hope this post answered some of your questions. Thank you for reading!