# tapping aluminum



## xochi (Oct 24, 2005)

I plan on tapping an aluminum fenix to screw on a pocket clip and have never tapped/threaded an aluminum flashlight before. Any tips on tools or procedure? I'm stuck with a hand drill or a dremel to make the hole.

I'll also be attempting to mill a groove with a dremel. Tips would be appreciated here as well.

Thanks, Ken


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## gadget_lover (Oct 24, 2005)

The tapping is fairly straightforward. Make sure you use the right size drill for the tap. Some taps sold at the hardware store come with the right drill bit for about $5.

I'm going to assume you know nothing at all, OK?

Using a hand drill, the trick is to make a dimple in the anodized case before you start to drill. This keeps the drill from drifting to the side. You can use a centerpunch or a small nail to make the dimple.

It's thin aluminum, so you should be able to drill it quickly and without problems. Make sure the body has no electronics that the metal shavings will foul. Make sure you won't drill into something inside the body by accident.

Tapping it is also fairly straightforward. I woudl clamp the light someplace where it's level and secure. Make sure the tap is straight up and down by examining it from all sides. Turn it gently and don't force it. Back it out every 2 turns.

I can't help you with cleanly cutting a groove with the dremel. I never do it right. I eneded up buying a lathe to compensate for my lack of skill in that area.

Daniel


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## McGizmo (Oct 24, 2005)

What Daniel said. In addition, I would add that some oil on the tap will aid in cutting the thread and it is OK if the hole you drill is slightly larger in diameter than what is specified as the proper pilot hole. Your screw is much stronger than the aluminium so you don't need a full thread profile in the softer material; it would shear at the root anyway.

On your groove, the dremel will want to walk so you need to brace against that. If I understand that you want to do a straight groove, brace or clamp the part and if you can, come up with something as a guide for your hand that is parallel to the grove cut and can serve as a "fence" or guide for your hand.


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## Kevin Tan (Oct 24, 2005)

Xochi, I wud discourage u from drilling the fenix. Theres not much meat left in the body. The batt hole is 14.6mm with 20mm outer above the 6 flats. 2.7mm thickness. U get 5 threads if u punch thru like a knife clip type. OK if its heat-treated 410 SS but alu....

Benchmade has ss inserts for 6al4v ti 750 pinnacle and 630 skirmish and 635 mini skirmish.


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## LED Zeppelin (Oct 24, 2005)

There is a great cutting fluid called "Tap Magic" in two formulas, the red can for steel and stainless, and the siver can for alum. It's widely available at industrial supply places in various sizes. It's really amazing how well it helps with hand tapping.
My second choice would be to use kerosene as a cutting fluid for aluminum. It's a decent substitute for Tap Magic.
For steel and stainless, heavier common oils work as well like motor oil or household oils.
At any rate, do your best to keep the pilot hole as close to ideal as possible. If I'm hand-drilling, I tend to use the next smaller drill bit (we're talking a couple thousanths of an inch or the next smaller bit in the lettered drill bit sets) so an unsteady hand will not create an oversized hole. Then carefully hand tap the hole, backing it out as soon as you feel an increase in resistance to clear the chips and cut the hole to the proper size. The reason you don't want too big a pilot hole is so that the load bearing surfaces of the alum are larger, and less likely to strip from tightening the bolt.
I do think Kevin has the best suggestion: Leave it alone. Trying to "mill" a clean groove with a Dremel would be quite some feat. I'm assuming that it is a groove around the body, not lengthwise. For a clean groove you would need to make a fixture that held the Dremel (perhaps a padded vice), and another to hold the light rigidly yet allow it to turn freely (like another bigger drill holding the light, clamped in another vise.) 
If it's a groove to hold a retaining ring, it would also have to have a clean cross section to seat the ring properly.
If you really want to do this, I would suggest calling aroung to various local machine shops, probably a small one that will take small (tiny) jobs, not the full blown CNC prodution shops. It shouldn't take a machinist more than 15-20 min. to do the work, and you might get off for $20-30 instead of ruining your light and spending another $40 to replace it.


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## gadget_lover (Oct 24, 2005)

Kevin Tan said:


> Xochi, I wud discourage u from drilling the fenix. Theres not much meat left in the body. The batt hole is 14.6mm with 20mm outer above the 6 flats. 2.7mm thickness. U get 5 threads if u punch thru like a knife clip type. OK if its heat-treated 410 SS but alu....




Others can correct me on this....

2.7 mm is close to an eigth of an inch. I've tapped thinner stuff and had it hold well. Add a drop of
loc-tite to make sure it does not back out and start wobbling and (in my opinion) it should be fine.

I read somewhere that the number of threads make a big difference. A 10-24 in 1/4 inch aluminum will fail faster than a 10-32 in the same instance. At some point the screw breaks before the threads. An 8-36 will hold better than a 10-24 was what I remember.

Good luck.

Daniel


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## LED Zeppelin (Oct 24, 2005)

gadget_lover said:


> Others can correct me on this....
> 
> 2.7 mm is close to an eigth of an inch. I've tapped thinner stuff and had it hold well. Add a drop of
> loc-tite to make sure it does not back out and start wobbling and (in my opinion) it should be fine.
> ...



Good advice. There should be enough stock to hold if the tapping is done properly, and the Loctite is a good suggestion. Fine threads will also help. Again, if you don't have the tools, and don't want to risk damaging your light, you might post a thread asking a fellow CPF member to do the work. I'd be happy to do the tapping for you for free (I have 8-32 and 6-32 taps), but I don't have a lathe to turn the groove. I'm sure someone here has a lathe and would be less expensive than a shop.
If you must try the groove by yourself, another thought is to clamp a couple of SS hose clamps around the light to help guide your Dremel. The bit will chew up the clamps some, but they would help some to keep the groove straight - not something I would want to try myself, but better than freehand.


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## xochi (Oct 24, 2005)

Thanks for all the great advice! I'm planning on going ahead with the clip myself but if anyone can recommend someone who could do a good job with milling the slot for a tritium vial, I'd sure appreciate the info. I'm sure I'd likely screw it up unless I spent a good bit of time building mounts and such. 

I plan on the groove running in line with the length of the light and being about about a centimeter long.


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## gadget_lover (Oct 24, 2005)

xochi said:


> Thanks for all the great advice! I'm planning on going ahead with the clip myself but if anyone can recommend someone who could do a good job with milling the slot for a tritium vial, I'd sure appreciate the info. I'm sure I'd likely screw it up unless I spent a good bit of time building mounts and such.




A simple short groove is fairly easy, since it does not have to be precice. I find that hose clamps make good straight edges for rodlike work. So do zip ties if I'm careful. The hard part is making it a consistant depth, but since you'll be backfiling it with epoxy that shoudl not be an issue.

Daniel


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## xochi (Oct 25, 2005)

Hey Daniel,

I'm a little confused about the hose clamps. Obviously , they would be excellent for holding the light stationary but are you also talking about using the "slits" in the clamp as a template for the groove?

Your post has boosted my confidence a bit and I'd really like to do the modding all myself (the few little mods I've done have been VERY satisfying!). I'm hoping to finish with a light that is as close as I've come to my perfect edc and with my time and effort removed from the equation I bet it'll end up pretty cheap!

Ken


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## gadget_lover (Oct 25, 2005)

xochi said:


> Hey Daniel,
> 
> I'm a little confused about the hose clamps. Obviously , they would be excellent for holding the light stationary but are you also talking about using the "slits" in the clamp as a template for the groove?
> 
> ...



I was speaking about using the side of the clamp as a guide. If you want to make a groove around the light (like for an o-ring), you place the hose clamp and use it to guide your cutting tool.

If you want a groove going lengthwise, you'd need a straight edge going from end to end. You could use a hose clamp to hold a straight piece of metal to use as a guide.

Was that clearer?

Daniel


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## Data (Oct 25, 2005)

What ever you do practice on an old flashlight or piece of aluminum several times first. 

Dave


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## Vee3 (Oct 26, 2005)

WD-40 is an excellent cutting fluid for aluminum. Very handy for drilling/tapping with the extension tube attached. I used it for 20+ years as a machinist (Mainly just for tapping since the machines usually had coolant systems on them) even when the company provided fancier stuff. Still use it today in my home shop...


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## gadget_lover (Oct 31, 2005)

So? How did it come out? 

Pictures?


Daniel


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## xochi (Oct 31, 2005)

Well , I haven't done it yet. I picked up a fenix from 4sevens and began the process of dismantling and ended up destroying the driver in it. It was a pita. I did do a little practice work (thanks Data!) with some aluminum crimps used to splice electrical services, and the dremel. I think the aluminum in these is alot softer than that used in flashlights and the results on the crimps wasn't encouraging. It looked like a smeared mess of a groove when I was finished. I'm trying to track down a v2.0 and I've called a few shops to ask about what the groove would cost if done professionally (about 20-30 dollars) .

At this point I'm not real sure what I ultimately end up doing as I'm focusing on other parts of the project since I'm not 100% certain that I actually have the host I'll ultimately use.


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## ottoluck (Nov 9, 2005)

Hi XOCHI; If you need a groove cut, I have a home machine shop and I am a Journeyman Toolmaker, send me a message of exactly what you want done along with the city & state where you are located. I can do it for a song, and overnight, I am disabled and help out a lot of folk's in need!. I can take care of that little tapping job also!. Either way you go, Good-Luck!!... Jim L.--


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## PEU (Nov 9, 2005)

Here is a guide for clearance and tap drills : http://www.blueangels.rchomepage.com/drill_and_tap.htm

Remember these machinist phrases:

Measure twice, cut once 

Is always easier to remove material than adding it back 



Pablo


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