Cant tighten locknut all the way

[mrwizard0]

I am trying to put a weldless dip tube on to my kettle but I can't get it to tighten down all the way to provide a good seal. I am following the directions on kals website. I was looking to see if anyone else has had this issue and how they fixed it. I also thought about heating up the locknut to see if it expands, does anyone think that will help? Thanks

 

[alien]

Is the thread NPS or NPT?

 

[mrwizard0]

I just found a thread about this. And honestly I don't know. I'm assuming its the wrong one otherwise it wouldn't be so hard. I think I should have nps correct?

 

[alien]

Yes, you want NPS. NPS will thread on all the way. NPT will not.

 

[mrwizard0]

Perfect thanks. I just order some from bargain fittings. I thought kal's site said npt.