What diameter to bore a 6P for 18650 battery?

[Chevy-SS]

I have a small lathe, perfect for boring out my Surefire 6P body. I'm thinking of just using a 3/4" drill bit (slightly over 19mm). Is this the 'standard' size for boring out the 6P body to accept 18650 batteries?

Thanks

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[ODatsBright]

The one time I bored anything for an 18650 I used a 19mm drill bit. Given that the cells seem to be pushing the limits of the specs for batteries, I'd just go with 3/4" and add a wrap of something if the batteries rattle.

My 2¢.

 

[Kestrel]

We hit this rather comprehensively in a recent thread here:
http://www.candlepowerforums.com/vb/showthread.php?t=273798
(Remaining wall thickess considerations of the host body, diameter of different brands of 18650's, etc)

 

[Chevy-SS]

We hit this rather comprehensively in a recent thread here:
http://www.candlepowerforums.com/vb/showthread.php?t=273798
(Remaining wall thickess considerations of the host body, diameter of different brands of 18650's, etc)

Many thanks for the link! I actually did a search and read through some threads. Didn't find that one though. Thanks again. :thumbsup:

My stock Surefire P6 appears to be ~17.5mm inside diameter. To enlarge it for a 18650, I think I will do an initial bore with a 23/32 drill bit (just purchased for $12 at Amazon), then fine tune as necessary with sandpaper on a dowel.

I did find a handy conversion chart, showing some of the relevant numbers. Hopefully this will help some:

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[old4570]

Try a 18mm drill bit ... It will most likely leave a hole ever so slightly over 18mm , which might just be right ...

Most 18650 go 18.1 / 18.2mm , perhaps a little more , 19mm = overkill
If some one knows a good drill size to use ? A good tool place may have numbered drill bits . [ 18 / 18.1 / 18.2 etc ]

 

[Chevy-SS]

I am posting the link in the quote below, as it is a great page with lots of measurements on 18650 batteries. Very nice page.

However, as Kestrel astutely notes here http://www.candlepowerforums.com/vb/showpost.php?p=3373462&postcount=10, boring to 19mm will leave the area under the o-rings extremely thin.

I would say 19 mm is a good diameter, then all 18650 cells will fit.
I have measured a couple of 18650 here.

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[DM51]

As suggested above, please continue in this thread.