How to loosen treaded end cap on a mini mag light?

Sounds like at some point the light was cross threaded to me.

If that is the case it is already damaged beyond economical repair.

Your tries are sensible, as I might well have tried the same, with maybe a tap hit along the way.

You might just force the issue and resort to duct tape, or send it to the manufacturer and see if they will give you another for good will purposes.

good answer, But dry ice would give even more shrink. If available.milo

You may be the victim of galling, if not cross-threading. In either case, Tornado's good answer of hot barrel/cold cap is your best bet for disassembly.

Then if it can be reassembled, apply some type of anti-seize compound to the threads before assembly and don't over-tighten.

Good luck.

A more extreme solution might be to apply a propane torch to the end of the flashlight. Of course if you do so, there is the possibility that it may destroy the light, but it will loosen the thing if it's galled or corroded.

The end is the male threaded cap. How does intense propane heat help with loosening?The barrel is female threaded and thin walled and contains the batteries. Not the best idea on this thread.

I believe I did specify that it would probably destroy the flashlight.

So the reason you posted was?

OK, As the originator of this thread I should add some information. This light is a special healing light for medical benefit. I don't want to destroy any part of it as you could imagine. However, this light was in the possession of a friend of mine who is this sort of absent minded professor type. In any event I believe he never used the item much and I don't know the history of why the end is not budging. Maybe it sat around for some time without opening the battery compartment. However I did notice that there is a little paint missing on the handle which leads me to suspect the he tried to vise grip it or something. I will ask. He said he couldn't open the battery compartment just a few days ago when I asked to borrow the light from him. So, I will try the hot cold method. It doesn't appear to be mis-threaded, how could I tell if it was ? Thanks for all the ideas.

Well one sure sign is that the threaded parts neither unthread, or thread back.

Another would be surfaces that are supposed to meet, don't.

Just because the light is special, doesn't mean it has not been broken.

I do again suggest that if excessive force is required by you to attempt what ought not take such excess, and you don't want to destroy the thing, to figure out what is wrong, your best option is to send it back to the manufacturer, and see what they might do, one way or another.

Hi Transcendian, Unfortunately the manufacturer is no where to be found. She was an acupuncturist living in Phoenix many years ago when I purchased one of the lights. She had a patent pending on the device, but I can't find her anymore. The light I own needs repair and so I remembered this friend had one too. He is willing to part with it but when he sent it to me this is the problem I found.

Some of the mini-mag lights had a look-a-like non-removable end.

If is removable then corrosion may cause to stick, then drill 3/32 hole through tube at the thread location at three points on the circumference then dip into coca-cola briefly to dissolve crud then remove with hot/cold method.

I had the same problem with my mag light ,which the batteries were left in too long and the acid ate into cap & barrel which parts may be available from mag light. I removed all good usable parts for future use and you may have to remove the end cap the best way you can but do not damage the tube or just a new mag and us what parts you need to make your's work .

Very true...as a friend's maglite recently demonstrated. The battery leakage in his was apparently less advanced than in yours; so he was able to remove the caps...the light even continued to work with the leaking batteries.

If anything of practical use is to be learned here, it's that Mag lites are particularly prone to battery leakage and leakage damage leading eventually to flashlight loss. One should not leave in batteries for extended durations of non use. I would suppose also that a little anti-seize compound on the cap threads might help prevent immovable caps as well.

The end cap does not have much wrenching surface. To increase the surface without marring the part, you might be able to find a two-piece clamp-type shaft collar of the right I.D., clamp it onto the cap, and apply a wrench to the outside of the collar.

Cross-threading might be indicated by a slight tilt of the cap, but if it were then wrenched down tight, several threads could be buggered up. Hope it ain't that bad....

on some mag lights the bulb end comes off and you can get to the batteries from there.

i think you will find red led`s will do as the frequency of red light is the same.

i find blue led`s work well

If the light has been sitting for a long time, the batteries may have leaked into the thread, corroding and seizing at the same time. I would dip the end in boiling water for a minute, then go at it with two vice grips.

Maybe one of these days the OP will actually try some of these ideas, and follow up with a report on what worked and what didn't. I would go for the non-marring options first.

Best chance is to get someone to machine a set of split collets to be clamped onto the barrel and the end. A split collet is just a piece of metal bored to a close fit on the object to be clamped and has a slit cut into the bore on one side. A screw or bolt is used to compress the slit and tightly clamp the object. This will not distort the body or the end cap which is important. If you distort them, they will not unscrew with any reasonable amount of torque.

Second choice is to use a strap wrench on the barrel and vise grips on the end cap. You can buy another flashlight and use its end cap. However, depending on what she did with the body, you may find that destroying it destroys the lamp forever.

I had a mini mag that had exactly the same problem......Soak it in vinegar overnight and you might get it apart. My problem was from corrosion caused my the batterys leaking. Good luck.

I restore antique telephones. Every now and then I find a stuck receiver cap. Being that some receivers are worth as much as $1000 it can be a touchy thing to remove the cap without breaking something. What works best for me is to place the entire receiver in the freezer overnight. Pull it out in the morning and the cap usually unscrews easily.

Interesting! I hadn't heard or thought of this before, but I can see how it might work.

Hi, Will putting this in the freezer affect the circuit board inside? Thanks

I'm sorry for interrupting here, but am I the only one who notices that the OP has stated this is a red, LED, {HEALING LIGHT!} ? Really?

Honestly, there are some good ideas for getting the end cap off of a mag light, but I promise you, there is NO evidence supporting the idea that RED LED lights heal anything!

There is nothing special about the light, if you STILL don't have the end off, toss it, and buy any other red LED light. Tell whoever you are using it on that it is "healing" them. It will do just as much good....

You were not, however we stayed focused on the engineering issue. There is no proof that many things have a mechanism for healing that people do; yet many people are healed unexplainedly by these non evidentiary methods. Labelling something as "placebo effect" only names it, does not explain it. When we get enough data about these types of healings, i suspect we will learn more about the human beings ability to self heal than we will about red light interacting with cytoplasm. I'm for giving the OP a break on this and lets help him solve his mechanical problem. milo

try resting the barrel on somthing solid ,and tapping the barrel all round where the threads are with a toffe type hammer ,keep turning the barrel and work yopur way round a few times ,this puts vibration in threads and breaks up the rust that maybe holding it .

When all else fails, read and follow the instructions....

OR

Hit it with a hammer, the universal fix-all tool!!!! *LOL*

JUST KIDDING!!!!!!!!

Two small strap wrenches or one small strap wrench plus bottle cap remover (as shown) might help.

The threads are aluminum on aluminum; not a good combination, but better than aluminum on steel/iron! Originally it included an O-ring for waterproofing; if that is still there, a penetrant won't get where it is needed.

Hot tube & cold cap is easiest to try, so do it first. My experience with strap wrenches on smooth surfaces is that they slip, but try it anyway and hope. The cap is too narrow for a strap wrench; can you clamp just the cap with a lathe chuck? Hopefully that will provide enough grip without the marring from a vice-grip or channel-lock. Tapping the OD is good to jar the threads and perhaps, possibly, maybe loosen them.

Be sure to let us know what works out of all these suggestions.

Some small devices have a cap that must be depressed before twisting. Just a thought.

If this is just a standard Mini Mag-lite with a special bulb, why not just buy another Mini Mag-lite and switch the bulbs?

Several decent ideas have been proposed on this thread. Long before now, the OP should should have tried the least destructive of them, and reported on the results. This has not happened. But then, we see that he/she believes in some notion of "healing light," which has only anecdotal support at best. Apart from the medical fraudulence of this unsupported claim, the rest of us should cease from replying to this dolt.

Fair enough. Other persons might benefit from these ideas. As for the OP, however, I no longer care. Cut it off with a hacksaw, an axe, or an air-arc gouger; I don't know if an oxy-acetylene torch works on aluminum, but why not? Just blast the crap out of this glorified flashlight.

If the batteries have corroded and leaked up into the threads, use a deap penetrating oil and set the light upright and let gravity do it's work, if you still can't get it off take it to a gun smith.