# BODY BORING



## MCFLYFYTER (Jan 24, 2010)

I can not find much info on boring bodys for 18650's. Any help would be greatly appreciated. I do not have the correct size reamer. My choices would be a drill or boring bar, both in a 17x33. Which one is capable of the best results in a 6P? Also, most people like to leave a lip to retain the batteries. Any idea how much lip to leave? I am guessing about 1,000 rpm for both drilling and boring? 

Thanks,
Russ


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## precisionworks (Jan 24, 2010)

An 18650 can run as large as 18.50 mm (.728"). A 47/64 drill bit is .734" and would be close to the correct size.



> I am guessing about 1,000 rpm for both drilling and boring?


Most aluminum alloys drill well at 250 to 300 sfpm. 1000 rpm equals 191 sfpm, a little slow but should work fine.

A boring bar, because is uses a single point cutting tip & has tons of chip clearance, can run lots faster ... 800 sfpm is a good place to start (if your spindle will run that fast) - 4200 rpm is the calculated speed. Most lathes (not counting high speed CNC machines) top out at less than that, so use the highest speed setting you have.



> Which one is capable of the best results in a 6P?


A boring bar allows sneaking up on the final dimension. Take a light cut, measure, cut, measure, etc.

A drill, perfectly sharpened, can do a nice job. Or it can grab, dig in, go off center, or mess up the work in every imaginable way.


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## MCFLYFYTER (Jan 25, 2010)

Thanks for the info. I ran a little test, and I think the boring bar will work just fine. I will just have to mess with the feed speed, and hopefuly by the final pass I will have it figured out. I will have to wait until tomorrow to get a dial, and to have more time to set it back up like I found it. Those machinists get mad if you monkey with their stuff and don't put it back EXACTLY like it was. Heaven forbid their lube brush is leaning the wrong direction.


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## wquiles (Jan 25, 2010)

> ... A boring bar allows sneaking up on the final dimension. Take a light cut, measure, cut, measure, etc...



The only thing to add is that depending on the material (steel or carbide) and the overhang (multiples of the bar's dia) you might have to take a "spring cut" - meaning that you leave the boring bar at the same setting and take 1 or 2 cuts at zero again. I was quite surprised the first time I took a spring cut - still cutting even at zero!


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## gadget_lover (Jan 25, 2010)

MCFLYFYTER said:


> I will have to wait until tomorrow to get a dial, and to have more time to set it back up like I found it. Those machinists get mad if you monkey with their stuff and don't put it back EXACTLY like it was. Heaven forbid their lube brush is leaning the wrong direction.




I imagine they get even madder if it LOOKS like it was as they left it, but is really a touch off in one axis or more. 

The nice thing about battery tubes is that the tolerances are not as demanding as some other parts. If you bore it a little large, or if bore 1 is slightly different than bore 2, it will usually cause no problems.

Daniel


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## wquiles (Jan 31, 2010)

I just finished one today:



















First used the boring bar to verify a centered body - just taking a very light cut:











Then I did a pass with a 23/32's (46/64") S&D drill and then a second pass with a 47/64" S&D drill (If I recall correctly done at 550RPM) using AccuLube LB2000 cutting fluid:






Fit is very nice, and not tight at all:






My notes and measurements (they do make sense in my head!):






EDIT: By the way guys, I am now using a smaller file size for the 800x600 images. Can you guys tell a difference in loading speed?

Will


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## gadget_lover (Jan 31, 2010)

Nice post Will. The pictures _seem_to be loading fast, but I'm on a different computer than normal, so I don't know.

You raise an interesting point about centering the work. You can center on the existing bore, which may be off center. But you can also center on the external surface of the light, but it occurred to me that it might also work best if you indicate off the part that will interfere with the boring, and that's the o-ring groove or the thread run-out groove.

Centering on the outside can make things interesting if the original bore is significantly off center. 

Daniel


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## 65535 (Jan 31, 2010)

In the future I would recommend keeping the boring bar as retarded in the holder as possible. I mean that it should have the lowest overhang possible. Not hugely critical here, especially seeing as you had a rigid setup for drill with the large S&D bits.


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## 737mech (Jan 31, 2010)

wquiles said:


> I just finished one today
> Will


 
Hey I recognize that light....


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## wquiles (Jan 31, 2010)

gadget_lover said:


> Nice post Will. The pictures _seem_to be loading fast, but I'm on a different computer than normal, so I don't know.


Good to know. The pics are about a 1/3 of the size as before, but they still look good quality-wise, so I will keep this smaller size for how.




gadget_lover said:


> You raise an interesting point about centering the work. You can center on the existing bore, which may be off center. But you can also center on the external surface of the light, but it occurred to me that it might also work best if you indicate off the part that will interfere with the boring, and that's the o-ring groove or the thread run-out groove.
> 
> Centering on the outside can make things interesting if the original bore is significantly off center.


Yup. It worked out well this time as everything was fairly well centered, but I still took the two steps (with the two S&D drills) so I would not be pushing things too hard.





65535 said:


> In the future I would recommend keeping the boring bar as retarded in the holder as possible. I mean that it should have the lowest overhang possible. Not hugely critical here, especially seeing as you had a rigid setup for drill with the large S&D bits.


Absolutely. In fact anything more than the very light cut would have been fairly futile here as the this Circle carbide boring bar was starting to "sing" as it was :devil:




737mech said:


> Hey I recognize that light....


You are right. It should look vaguely familiar


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## sardo_67 (Feb 12, 2010)

i have a 6P and an 18650 i want to put in it. my brother works in a machine shop and took the body on the lathe, we did not finish because we were concerned with the end thickness near the tail cap where the O-ring groves are. is this just something that happens and is normal or are we doing something wrong?


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## cmacclel (Feb 12, 2010)

Will I'd be careful using drill bits for boring work. The only time I have had things *slip* in the chuck is when drilling. This to me would have been a 100% boring bar job 

Mac


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## StrikerDown (Feb 12, 2010)

cmacclel said:


> Will I'd be careful using drill bits for boring work. The only time I have had things *slip* in the chuck is when drilling. This to me would have been a 100% boring bar job
> 
> Mac



And look at the long chips he is getting! I am certain if I tried drilling this thin walled body this with a drill this big it would grab the whole enchilada and rip it right out of the chuck in a mess of aluminum scrap!  Of course I don't have the advantage of a 6 jaw either!:twothumbs


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## wquiles (Feb 12, 2010)

cmacclel said:


> Will I'd be careful using drill bits for boring work. The only time I have had things *slip* in the chuck is when drilling. This to me would have been a 100% boring bar job
> 
> Mac


Point taken Mac. That is why I decided to do peck drilling (cut, back-out, clean chips, re-lube, cut some more, repeat), and why I decided to do the boring in two steps, first with the 46/64", and then with the 47/64" drill, again with lots of lubrication - I certainly did not wanted to push my luck.




StrikerDown said:


> And look at the long chips he is getting! I am certain if I tried drilling this thin walled body this with a drill this big it would grab the whole enchilada and rip it right out of the chuck in a mess of aluminum scrap!  Of course I don't have the advantage of a 6 jaw either!:twothumbs


Yes, the gripping power spread over 6 contact surfaces is awesome. I can't say enough of how much the 6-jaw makes things so much easier.


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## sardo_67 (Feb 13, 2010)

but as far as the thin part near the end that's just normal?


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## will (Feb 13, 2010)

When you are boring for a larger battery, centering is not all that important. The work should at least look like it is centered in the chuck. 

I always check the diameter of any external grooves before I bore something out. That is one thing you learn the first time you make a mistake. 

I rarely use a drill to open up an existing bore in a lathe. Too easy for the drill to grab. And, a drill will follow an existing hole, a boring tool will cut a hole that is centered in the chuck.


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## precisionworks (May 12, 2011)

I ordered the SureFire 6PX Pro, thinking it will be a nice utility light. Of course, it makes sense to run the same 18650 (2900mAh AW protected cell) that is used in the Catapult V2. Which got me thinking about boring, as did the recent thread by Shao.

I agree with all those who recommended against using a twist drill. Drills often make an oversized hole, that hole is rarely straight, and the surface finish is ... not so good. As Will Q pointed out, a .500" boring bar, or even a .625" boring bar, will be hanging out into the next time zone to go all the way through a two cell body. But, it's the best place to start.

My plan (when the 6PX arrives) is to bore the hole to 95% of callout, then ream the last 5% with a straight shank chucking reamer. I need to measure the AW18650's, but say that they mic a little under 18.5mm (.728"). That means boring to about .690"-.695" (nothing smaller) and reaming the last bit. It should work well.

May buy a BRM FlexHone for final finishing, but that's more for appearance than anything else. Plan to do this in the 4-jaw using some type of shop made soft jaws.

More to follow ...


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## metalbutcher (May 12, 2011)

You guys have peaked my curiosity. Do you make these flashlights totally from scratch or do you buy kits and finish them? Sorry for the rather ignorant question but I joined the forum for the excellent tool and machining advise I see on here.

Ed


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## gadget_lover (May 12, 2011)

We do both. 

Some have specialized in modifying existing lights. Look at some of Wquiles posts for some really great looking MagLites that have been sculpteds.

Others build their own. A small light (1 or 2 cells) is easy to do on a home lathe. It just takes time. Lots and lots of time.

Dan


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## precisionworks (May 12, 2011)

> I need to measure the AW18650's, but say that they mic a little under 18.5mm (.728"). That means boring to about .690"-.695" (nothing smaller) and reaming the last bit


As expected, the AW18650's are not perfectly round - they mic about 18.48 at the fattest part. Reaming to 18.5mm is not going to be large enough.

Checked my Catapult V2 and the ID is 18.75mm. Also checked a 5Mega tube (fits Surefire 9P) and it measured 19mm. The 18.75mm size is what I'm going with for now. MSC offers one in exactly that decimal size, .738". 

FWIW, the 5Mega tube is pretty thin at the rear O-ring ... .751 ID, .779 OD at the O-ring. That leaves a wall thickness of only .014". Aluminum is stronger than I thought, as that tube has seen some hard use and it's still in one piece 

If the Surefire tube measures the same .779 at the O-ring, and the ID is reamed to .738, the walls will be .020" thick. That sounds a lot better than .014"


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## precisionworks (May 13, 2011)

I knew this thread would end up costing me :shakehead

Ordered the reamer that should do the job for most "normal" diameter batteries, .738" diameter. Also ordered the next size up, .750", to use for a battery that is slightly over size. Didn't stop there ... ordered a BRM Flex-Hone BC: http://www.brushresearch.com/







What the heck, it's only money :nana::nana::nana:


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## will (May 13, 2011)

The only reamer I have been using has been a 5/8 inch. I use that for the various wood projects that I have worked on over the years. I use the reamer for a true bore in the wood, that in turn allows me to put that on a 5/8 inch arbor that I use in my mini lathe. 

I have bored out a number of Solarforce L2 lights for the 18650 batteries. ( you can buy them that way now ), I just use a home made boring bar. I some times use an old machinist trick - do the final bore a second time at the same setting ( this works nicely on aluminum ) This will generally take care of any 'walking' that the boring bar might do.


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## precisionworks (May 13, 2011)

> I some times use an old machinist trick - do the final bore a second time at the same setting ( this works nicely on aluminum ) This will generally take care of any 'walking' that the boring bar might do.


Taking a second (or third) cut at the same setting, aka a "spring cut", does a good job of equalizing the inside diameter of the bore.

Boring alone is sometimes "good enough" for many jobs. Boring *usually *produces a cylinder that is on size, circular, and concentric with the outside diameter. The problem with a fairly deep bore in a small hole is that of bar (actually insert) deflection. A steel bar should be extended no more than 4D, and a solid carbide bar no more than 8D ... that's only 2" of projection for a 1/2" diameter steel bar. Even using the very best insert (high positive shape designed for aluminum) this is a challenging job. 

The reamer takes a bore that's at 95% of full size and opens it up that last little bit. The reamer also assures that the bore has no taper (which can happen with a boring bar). And it leaves an awesome surface finish, comparable to the very finest boring job possible, about 16-32 Ra. 

Honing takes that 16-32 Ra surface and refines it to about 4-8 Ra. If a finer surface is needed, polishing or lapping will produce a 2-4 Ra surface.

Will a bored tube work? Sure, most of the time it will do just fine ... and most of the time a Ray-O-Vac flashlight will do a good job :nana:


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## will (May 13, 2011)

precisionworks said:


> Will a bored tube work? Sure, most of the time it will do just fine ... and most of the time a Ray-O-Vac flashlight will do a good job :nana:



Keep in mind - I am only referring to a battery tube, not a precision bore that another part has to mate with. Also - as pointed out above, not all batteries are perfectly round. Reamers certainly have their place, they yield a great finish, will eliminate any taper, and cut to a consistent size time after time. Boring works well for the limited amount of work that I do.


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## precisionworks (May 13, 2011)

FWIW, smoothness & roughness of machined finishes are usually expressed in Ra (Roughness average). Although there are extraordinary tools available costing thousands, a simple surface comparator is enough for many shops (including mine). These retail for around $100 & often sell for $15-$20 on eBay.






On the left side, the Ra starts at the bottom (roughest) at 63, then moves up to 32, etc. I consider "smooth" as 10 Ra or better, doable with good reaming technique followed by a super fine (800 grit) ball hone.

The right side of the chart starts with 500 Ra (rough turning or rough milling) and goes to 16. It's all but impossible to get better than a 16 finish by milling or turning, including boring. On rare occasions, running 1144 Stressproof, I've seen 10 a time or two.


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## metalbutcher (May 13, 2011)

gadget_lover said:


> We do both.
> 
> Some have specialized in modifying existing lights. Look at some of Wquiles posts for some really great looking MagLites that have been sculpteds.
> 
> ...


Dan,

Thanks for the information. Is there a section of this forum for total newbies to this craft that would get me started? I searched but could not find anything specific to newbies just getting started. Sorry to be a pain so let me know if this is not an appropriate question for this thread.

Ed


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## gadget_lover (May 13, 2011)

The "Homemade and Modified Flashlights Discussion" forum is a good one for beginners, since they discuss every aspect of building custom lights. If you look at enough threads you will find something for every aspect.  .


http://www.candlepowerforums.com/vb/forumdisplay.php?17-Homemade-and-Modified-Flashlights-Discussion

Daniel


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## wquiles (May 13, 2011)

gadget_lover said:


> Some have specialized in modifying existing lights. Look at some of Wquiles posts for some really great looking MagLites that have been sculpteds.


Thank you Dan for your kind words and for all that you have taught me here in this forum :bow:




metalbutcher said:


> Dan,
> 
> Thanks for the information. Is there a section of this forum for total newbies to this craft that would get me started? I searched but could not find anything specific to newbies just getting started. Sorry to be a pain so let me know if this is not an appropriate question for this thread.
> 
> Ed


 
Ed,

If you are refering to a guide to get started with modifying flashlights, or a foundation at a high level, I created such a post about a year ago, which might be of help:
Introduction to modifying flashlights

Will


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## gadget_lover (May 13, 2011)

I'd forgotten about that one Will. A VERY nice write-up. I'm proud to have contributed in any small way

One of the things I like about CPF is that we all get to learn from each other. Even those who are professionals will share and learn with the rest.

Like Will (and many others) I knew nothing about machining when I modded my first light. I knew even less by the time I used my lathe to alter the first AAA flashlight body. ( http://www.candlepowerforums.com/vb/showthread.php?49598-2aaa-Dorcy-with-LD-luxeon-custom ) 

If you spend enough time reading and then trying what you read, you will find that, even with small equipment, you can master most of the skills needed.

Daniel


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## metalbutcher (May 14, 2011)

Will & Daniel,

Thanks for the links. :thumbsup:

I'll take a look at them and start a new thread when I have questions. I've mostly made tools and repair parts for stuff around the house with my metalworking machines. Now I'd like to start making something useful that everybody could use and flashlights certainly fit in that category. I'm not into making models or that kind of stuff that just sits there to look at. I like making useful things. I'm not bashing model making and similar activities, it's just not for me.

Thanks again,
Ed


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