# Reamer for 18500 Li-ions



## Tekno_Cowboy (Aug 8, 2009)

I'm looking at getting a reamer for 18500 Li-ion lights, and I was wondering what would be the best size for it. My first thought was 3/4" as it would give plenty of room for the roughly 18.5mm wide cells. Is there a size that would work better?


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## darkzero (Aug 8, 2009)

That would work fine & leave plenty of room for variances in different brand cells. My MM splt body actually measures exactly 19.05mm so I assume a 3/4" reamer was used? My 18650s fit pretty loose in there though. Lion Heart & Dragon Heart measure about the same.

I only have AW protected 18650s & none of them measure over 18.4mm at their widest point. A 0.730"/#49 reamer would probably be the absolute smallest you would want to go. I would choose 0.735" or 0.74" if you want a better fit than 3/4" & still have a bit of room (all $14 @ Enco). Although my AWs fit loose in the MM body it's not an issue at all.


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## will (Aug 8, 2009)

I bored out a number of lights at .740 inch...

3/4 inch might be a little to big..


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## Tekno_Cowboy (Aug 8, 2009)

So .740" would be a bit better. I'd like to make sure that most cells will fit, but not so loose that most of them rattle around.


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## Torque1st (Aug 8, 2009)

I use a piece of heavy paper inside flashlight bodies to keep smaller cells from rattling around.


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## precisionworks (Aug 8, 2009)

Will you machine ream these in the lathe? If so, run the reamer at half the speed you'd run a drill, and feed twice as fast, with plenty of Tap Magic or similar cutting oil. Hole size before reaming should be .010" to .020" smaller than final reamed size.


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## wykeite (Aug 8, 2009)

Adjustable reamer is the way to go, 18.65mm seems to accomodate most if not all rechargeables.


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## gadget_lover (Aug 9, 2009)

When I have rattle, I add my name and contact information to a slip of paper and wrap it around the batteries.

This did not help at all the last time I lost a flashlight. It was never returned.

Daniel


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## Mirage_Man (Aug 9, 2009)

darkzero said:


> That would work fine & leave plenty of room for variances in different brand cells. My MM splt body actually measures exactly 19.05mm so I assume a 3/4" reamer was used? My 18650s fit pretty loose in there though. Lion Heart & Dragon Heart measure about the same.
> 
> I only have AW protected 18650s & none of them measure over 18.4mm at their widest point. A 0.730"/#49 reamer would probably be the absolute smallest you would want to go. I would choose 0.735" or 0.74" if you want a better fit than 3/4" & still have a bit of room (all $14 @ Enco). Although my AWs fit loose in the MM body it's not an issue at all.



A reamer was not used during production of the split-bodies, a boring bar was. The decision to go with a slightly larger I.D. was to accommodate the largest 18650's being used, the PILA, which is both longer and fatter than AW's cells.


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## KC2IXE (Aug 9, 2009)

precisionworks said:


> ...snip... Tap Magic or similar cutting oil. Hole size before reaming should be .010" to .020" smaller than final reamed size.



I still thing original formula Alumi-tap(still available) or if you can find it, original formula Tapmagic are the best - of course they have those nasty chlorinated solvents in them....


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## darkzero (Aug 9, 2009)

Mirage_Man said:


> A reamer was not used during production of the split-bodies, a boring bar was. The decision to go with a slightly larger I.D. was to accommodate the largest 18650's being used, the PILA, which is both longer and fatter than AW's cells.


 
Thanks for confirming Brian. 

Based on this answer I might as well ask what I was wondering. Why use a reamer here? I understand the benfits of using a reamer but is it really needed for this? Since you'll need to bore within 1-2 hundredths of the final diameter anyway to use a reamer, why not just bore to the final diameter instead of having to change tooling. I know it's not all that much work to pop in a chuck & a reamer but since you're target final diameter will leave you plenty of room is the extra precision & finish critical? Unless maybe if you're doing a bunch of them & want consistant results? I can't say I've bored a lot of bodies but I've bored a number of Surefire bodies which all came out great but the use of a reamer never crossed my mind here. Just wondering.


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## Tekno_Cowboy (Aug 9, 2009)

I was just thinking that it would speed things up a little. Instead of being careful not to shoot over, I can just get close, and then run 1 tool and know that once it's run, it will be within a few thou of what I want. For about $15 for a reamer, I figured it couldn't hurt.


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## darkzero (Aug 9, 2009)

I see. Every little bit of insurance to prevent screw ups is worth it I guess & definitely worh the $15 here. I was thinking more in terms with SF E-series bodies that have the smaller tail end. Would be too much trouble to use a reamer since I don't have any kind of DTI or DRO on my tailstock so I'd be more afraid of going too far. For a straight through 18650 body there would be no worry.

I've never bored anything that large & deep using a reamer. The largest I have & used is a 0.1495. Since the flutes are straight does it clog up easily when boring deep? Supposed to use a "peck" style method? Do HSS reamers last pretty long when only used with non-ferrous metals?


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## cmacclel (Aug 27, 2009)

I bought some 18.5mm Carbide reamers on Ebay.......they just sit in my draw  I thought the same thing......

Mac


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## precisionworks (Aug 27, 2009)

> Since the flutes are straight does it clog up easily when boring deep?



Reamers have multiple flutes, and each flute is deep relative to the small amount of material removed by each cutting edge. I've never had one pack or clog with shavings, but there are always some shavings in each flute.



> Supposed to use a "peck" style method?


You normally want to feed all the way in, or all the way through, in one smooth, continuous motion.



> Do HSS reamers last pretty long when only used with non-ferrous metals?


Close to forever, as long as the speed (SFPM) is correct. Heat can kill the delicate cutting edges, so plenty of your favorite lubricant & correct speed are essential.

HSS reamers also last a long time in carbon steel with proper lube & speed.

Reaming produces a hole that is straight, cylindrical, correctly sized, with beautiful surface finish. You can produce that same hole with a boring bar but it takes many times longer, especially for size critical holes like the ones for a dowel pin or locator pin.


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## Tekno_Cowboy (Aug 27, 2009)

[URL="http://www.candlepowerforums.com/vb/member.php?u=2664" said:


> cmacclel[/URL]]I bought some 18.5mm Carbide reamers on Ebay.......they just sit in my draw  I thought the same thing......



If the hole those make fits an 18500-18650, I'd be willing to take one off your hands, if you're not using it


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## Tekno_Cowboy (Sep 9, 2009)

I'm planning on ordering a 47/64" reamer sometime tomorrow. it should give a pretty snug fit for 18 mm cells, without being too tight.


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## Tekno_Cowboy (Sep 16, 2009)

I got my reamer in today 

I managed to use it on my 6P, and it turned out OK, but I think I'm going to need some more practice before I use it on something important.


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## precisionworks (Sep 16, 2009)

> I think I'm going to need some more practice before I use it on something important.


Two really critical issues with machine driven reamers are alignment & lubrication. The bore has to be in perfect alignment with the reamer, which is often easier to do on a mill or a drill press than on a lathe. Speed is slow, half of drilling speed, with feed twice as fast as a drill. If you think there's enough lubricant on the reamer, add more:nana:

Run correctly, surface finish should be somewhere between excellent & awesome. The flutes are really easy to nick, especially if the reamer is not stored in a protective plastic tube. A nicked flute will leave a machining mark in a bore. If you can see a nick under magnification, or feel one with a finger nail, stone it out with a hard Arkansas stone, or an extra fine diamond stone.

Reamers can be resharpened, but they shrink a little with each trip.


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## Tekno_Cowboy (Sep 16, 2009)

I'm betting 620RPM was _way_ too fast....

Next time I'll have to run it a bit slower.

The alignment isn't too difficult, all I have to do is put a dead center in both the tailstock and the chuck, and drop the reamer onto my QCTP. Lining it up is easy as pie from that point. It was tricky as heck getting the height right though...


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## precisionworks (Sep 17, 2009)

> 620RPM was _way_ too fast


No and yes 

Reamers can be run in aluminum at 300-400 sfpm. At 620 rpm, your speed was 114 sfpm, well below the maximum listed speed.

The problem is that the tool is trying to remove a tiny amount of soft material while leaving a very high surface finish, which is really tough to do at 620 rpm. Try dropping the spindle speed to around 100 rpm & use the power feed to give a fairly slow, controlled cut. A few tries on some scrap aluminum tubing are well worth the time it takes and you'll find the sweet spot for that tool. Again, lots of lube.

Here's a good sfpm table that lists most materials:

http://www.vm68.com/stuff/sfpm.html

And this is the online calculator that I use all the time:

http://www.carbidedepot.com/formulas-turning.htm



> tricky as heck getting the height right though


That's the hard part about lathe reaming. If you can get a reamer with a Morse tape shank that fits your tail stock, the job is much easier. Then the reamer is either fed with the tail stock wheel or the tailstock is pushed by hand - which works a lot better than it sounds


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## Atlascycle (Sep 17, 2009)

Why not just use a chucking reamer in the tail stock chuck?


Jason


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## Tekno_Cowboy (Sep 17, 2009)

I'll try that suggestion with lower rpm's and the power feed. Thanks for the links and info :thumbsup:

I'd like to use one in my tailstock, but I'd need to cut off about 3-4 inches and turn the shank down to 1/2 inch, or get a 5/8" chuck. 

A tapered shank reamer would be nice, but I have yet to find one this size.


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## wquiles (Sep 29, 2009)

Travis,

For the 18650 Delrin spacers that I sell with my 1xD customs, I have to of course make a hole in the Delrin. Previously I used a 5/8" drill and then bore it out to size, and that seemed to work well for the relatively few number of spacers I was selling. Now that I am doing more of them, I decided to try with a larger S&D drill, and also with a reamer, so I want to pass on my own results.

First, note that 18650 cells come in various diameters depending if the cell has protection or not. I happen to have perhaps the fattest 18650 on the planet, since it likes to have a hole of about 0.73" in dia., which is just a tad more than the 18.5mm (0.7283") traditional reamer used for these cells - because of this, I always use this "fat" cell for testing anything I am building that uses 18650 cells.

I first tried using a 46/64" (23/32") S&D drill, but the hole came too small at 0.714" for my fat cell (theoretical hole 0.71875"). I then tried enlarging that with a 47/64" reamer, and the hole came to 0.714" (theoretical hole 0.73438"). I finally tried a S&D in the 47/64" size, and came up with a 0.736" hole. So as expected, using the 47/64" reamer to expand the 46/64" hole gave me a more accurate hole, compared to using the 47/64" drill. 

For my application, both undersized 46/64" & 47/64" reamer and 47/64" drill work equally well, so of course I will simply use the 47/64" drill as it is a single step/tool, but I should also note that the resulting internal finish of the undersized 46/64" & 47/64" reamer combo was much smoother/nicer than the hole made with the 47/64" larger drill. Again, this was with Delrin material, so when using on Al your results might be a little bit different. Next time I will take measurements with my micrometers to get more accurate readings as my Starrett #123 caliper only measures down to 0.001".








(it is funny in this second picture how the perfectly straight reamer looks bowed due to the wide angle lens used!)






Will


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