# Nitecore tailcap from the MT/SRT series.



## NeilP (Dec 22, 2014)

Any one happen to know the thread type used in the Nitecore tail cap from the MT/SRT series.?

I am turning my own host to use with one of these tail caps.

I never had the host to measure the body thread, and measuring the cap threads is proving difficult.


I can't even get the switch out. 

I assume it unscrews using the two recessed holes but the disk is extremely tight . May try heating git tomorrow. but stopped today before causing damage.



Thanks


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## jonwkng (Dec 23, 2014)

Hey Neil,

I'll try to get the information about the MT06 once I get my hands on mine

The MT/SRT series span in size from AAA(MT06) to AA(MT1A,MT2A,MT21A to CR123/18650(MT1C,MT2C,MT25,MT40,MT26,SRT3,SRT5,SRT6,SRT7) in width. So you're gathering thread information for all of them?

Yes, the switch should unscrew using the two recessed holes as leverage. Needle-nosed pliers or tweezers should do the trick (Though I've used disposable chopsticks at times) .


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## NeilP (Dec 23, 2014)

Great, thanks


I have an 18650 tail cap, though I'd say that although the diameters are going to be different, I'd be 99% certain they would be using the same thread profile and pitch /tpi for them all.





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## NeilP (Dec 23, 2014)

I thought that was the way to open the cap, and did try with circlip and needle pliers. Even with pliers in vice and rubber 'gator' tube wrench on body it did not move.

I am going to drill the holes a little deeper, just half a mm or so, heat with hot air gun and try again



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## NeilP (Dec 23, 2014)

The heat and deeper drilled holes did the job, but unfortunately the ring that holds the switch assembly in place is a different thread, it is on a shoulder . so measuring that thread has not helped.

It did give beer light in to the cap body though, and I think that the thread pitch maybe 20 threads per inch, but I can't be sure.

Any one happen to know if Nitecore use imperial or metric dimensions?

Seems strange that any one would still be using imperial threads nowadays. but maybe ??


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## jonwkng (Dec 23, 2014)

Hi Neil,

Didn't realize you were looking at the 18650-sized tubes. Anyway, the tail threads on the 18650 lights across the MT, P, MH, C, SRT lines are all triangular cut and share the same thread pitch - the NiteCore remote switch is compatible across the 18650 lights in these series.

I do not have a thread gauge with me, but if anyone who has can probably check any of the lights I mentioned and you'll have what you need.


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## NeilP (Dec 23, 2014)

well it did a cut on test piece this afternoon. at imperial 20 TPI but i binds very soon.

It may well be metric 1.25 pitch

Internal diameter of the female thread is 20.95 - 21.00mm, 

trouble is it is near on impossible to get a thread gauge inside the cap to measure..so the external host thread needs to be measured.


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## NeilP (Jan 3, 2015)

Well I tried a 1.75mm metric cut this afternoon and it is not that either.


If there is any one that has one of these Nitecore lamps, would be great if they could post a picture of the thread at the tail cap end, as close as possible, and next to a tape measure would be great.


Nitecore don't respond to any Customer Service requests, so you guys are my only hope.


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## ACruceSalus (Jan 3, 2015)

Here's a picture of my SRT7's tailcap threads. I took pictures in this position and on its side and this was the best one I'm able to do.


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## NeilP (Jan 4, 2015)

Thanks for trying that for me. But it is the tailcap that I do have, and the host tube that I do not. 

I have the same issue that you too have come up against that it is difficult to see the thread pitch at that angle.

Do you have the host that the tail cap fits? A picture of the matching host threads would me much easier as you can get straight over the top.


Thanks again

Neil



What


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## NeilP (Jan 4, 2015)

Solved using chewing gum, baby oil n the cap and a freezer!


1.25mm pitch


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## ACruceSalus (Jan 4, 2015)

I fiddled with that thing for quite awhile trying to get a good picture but it looks like I didn't follow the old adage "measure twice cut once" and ended up the the wrong picture. It's good though to see that you figured out a way to get the measurements. I like the 'bubble gum" engineering method. We've had to use it to temporarily to fix our car's gas tank.


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## NeilP (Jan 4, 2015)

Thanks for making the effort though, much appreciated.

I have been struggling with this for a week or more, why it took me so long to figure out that solution I'll never know. Not ' techy ' enough I guess

Got the thread cut too today.







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## ACruceSalus (Jan 5, 2015)

Looks nice. I have those moments too when I wonder why I didn't think of something sooner.


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## NeilP (Jan 5, 2015)

Its for the other end of a Suprabeam Q2. Q2 is single AA., with great zoom
Using the zoom head on home made 18650 host. Needed the bigger tail cap to get the cell in. Other way would have been to use the original
AA cap and adapter ring.














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## NeilP (Jan 5, 2015)

Deleted multiple post from the stupid iPhone app after phone locked up


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