Need a measurement real quick, diameter of a 18650? [HELP]

[M52 POWER!]

Hey I'm not at home and bringing a flashlight body to be bored out for a 186500 to a machinist. I forgot to measure the diameter of a 186500 (Doh!), could anybody measure it real quick for me please?

Thank You!!!

 

[UberLumens]

Re: Need a measurement real quick, diameter of a 186500? [HELP]

I think you mean 18650

18MM wide 65MM long (some vary)

 

[M52 POWER!]

Re: Need a measurement real quick, diameter of a 186500? [HELP]

THANK YOU!!!!!

 

[JCD]

Re: Need a measurement real quick, diameter of a 186500? [HELP]

The numbers utilized to identify cells have meaning. Take 18650, for example:

18650

The 18 represents the cell's diameter, in millimeters.

The 65 represents the cell's length, in millimeters.

The 0 indicates that the cell is round.

Thus, a 17670 cell is 17 mm in diameter, 67 mm in length, and round. A 16340 cell is 16 mm in diameter, 34 mm long, and is round.

Note that some cells are not manufactured exactly to specification, and might me slightly wider/narrower or longer/shorter than their numerical size might indicate.

 

[DM51]

Re: Need a measurement real quick, diameter of a 186500? [HELP]

Moving this to the Batteries section...

 

[M52 POWER!]

Re: Need a measurement real quick, diameter of a 186500? [HELP]

Good to know, that makes more sense. I'll have it bored to 19mm then for tolerances, or is that too much?

 

[Kestrel]

Re: Need a measurement real quick, diameter of a 186500? [HELP]

Good to know, that makes more sense. I'll have it bored to 19mm then for tolerances, or is that too much?

Yes, 19mm is excessive IMO - the wall thickness will be far too thin.
What cells (i.e. what manufacturer) will you be using?
I would recommend 18.6 mm ID for starters - many 18650's are approximately 18.4 mm OD.

My AW 2600 mAH 18650's measured .729" OD
I have one light bored to .734" and it is an excellent fit.
I have another light bored to .741" and IMO it is a little more oversize than necessary.

I think that .732" would be about perfect for my AW 18650's. Your cells may be slightly different.

Edit: The nice thing with the AW cells is that silver label. If you get a good initial fit after boring, good. If it ends up being too tight, I would just peel off the label to get an extra few thousandths clearance - that way you've retained the maximum of body material. My two lumens,
K

 

[DM51]

I assume the extra "0" in the thread title was a mistake, so I've edited it.

 

[HKJ]

I would say 19 mm is a good diameter, then all 18650 cells will fit.

I have measured a couple of 18650 here.

 

[Kestrel]

I would say 19 mm is a good diameter, then all 18650 cells will fit.

The OD for a typical SureFire 6P (measured at the thinnest point, the tail o-ring grooves), is ~0.771" (19.6 mm) with a wall thickness of ~ 0.042".

Taking the ID to 0.734" (18.6 mm) results in a wall thickness of 0.0185". IMO this is optimum for the AW 2600 mAH 18650's, providing a clearance of only ~0.006" (~0.003" on each side) for my particular cells.

Taking the ID to 0.741" (18.8 mm) results in a wall thickness of 0.015".

Taking the ID all the way up to 19.0 mm would result in a wall thickness of only 0.011", ~1/4 of the original wall thickness. This is the same thickness of a typical paper business card, which would concern me with regards to structural strength.

I have measured a couple of 18650 here.

That is a good resource. My AW 18650's measured the same as yours, BTW. The OP does need to consider what cells he will be using.

 

[march.brown]

The internal diameter on my Solarforce L2 torch is 0.749" which is about 19mm ... My Ultrafire protected 18650 cell is 0.735" at its widest and 0.717" otherwise ... The widest measurement is due to the conductor from the positive end of the cell going to the protection circuit being under the shrink wrap ... So if you are using a protected cell , I would go to 19mm bore (0.749).

Don't bother having the torch bored out , just buy a Solarforce L2 instead.
.

 

[jasonck08]

I would go for at least 18.7 or 18.8mm. I have cells that are about 18.6mm, but thats the biggest. Most are 18.4mm or less.

 

[M52 POWER!]

Yea when I got home i measured my cells and they come in at 18.6mm. Measuring one of my other torchs that takes 18650's it shows 18.74mm.

 

[Chevy-SS]

I would say 19 mm is a good diameter, then all 18650 cells will fit.

I have measured a couple of 18650 here.

That is a terrific page! I think it could benefit from the addition of this chart showing some sizes and conversions:

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, then fine tune as necessary with sandpaper on a dowel.

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