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An engineering challenge for you

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An engineering challenge for you

Old 21st May 2020, 08:02
  #41 (permalink)  
 
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Originally Posted by double_barrel View Post
I tried a variant of this. Two holes in the cap with large screws into each. THen a big screwdriver between them. I applied enough force to bend the screws without any movement of the cap. It really is for the bin now.
But have you kept the cap end submerged for a week in penetrating oil. Or diesel. Or a 50/50 mix of acetone and red automatic transmission fluid?

And have you managed to get penetrating fluid into the inside of the battery compartment as well?

A guy on Salvage Hunters: The Restorers was given an ancient mechanical till or adding machine, I forget which. It was rusted to buggery and absolutely seized solid.

He kept it submerged in diesel for a week, and it eventually freed off.
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Old 21st May 2020, 08:09
  #42 (permalink)  
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Originally Posted by Uplinker View Post
But have you kept the cap end submerged for a week in penetrating oil. Or diesel. Or a 50/50 mix of acetone and red automatic transmission fluid?

And have you managed to get penetrating fluid into the inside of the battery compartment as well?
It had 36 hours in wd40. But that was before I made holes into the battery compartment. I suppose I could try that again.
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Old 21st May 2020, 08:27
  #43 (permalink)  
 
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Yes. Use actual penetrating fluid, (as #41above), and leave the end cap fully submerged, inside and out, for a week.

Mag Lites, and probably Lensers, have a rubber seal in the end cap to keep external moisture out. This seal will prevent penetrating fluid getting in, so you need to get fluid into the inside of the battery compartment to get at all the thread.

To get fluid to the inside, drill a small hole in the centre of the cap. If you extend one of the two screw hokes you drilled, you might catch and bugger the battery spring.

Last edited by Uplinker; 21st May 2020 at 08:39.
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Old 21st May 2020, 08:38
  #44 (permalink)  
 
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Another vote for PlusGas from me, it really is effective.

Amazon Amazon
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Old 21st May 2020, 08:53
  #45 (permalink)  
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OK, next question, how do I extract a pint of diesel from my car?! This has potential to turn into a cluster****!
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Old 21st May 2020, 09:53
  #46 (permalink)  
 
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Petrol can next time you fill the car?
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Old 21st May 2020, 12:47
  #47 (permalink)  
 
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Not sure how many ppruners have contributed, as some have made a number of contributions in 47 posts.

However, I am much taken with the efforts to salvage things - over many hours and much wasted man-cave necessities, to save things that are a couple of pounds on e-bay/tesco.

Some, such as Uplinker, have probably wasted many hours of very valuable drinking time, and many bits of man-cave essentials to save UKP2.50p
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Old 21st May 2020, 13:28
  #48 (permalink)  
 
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Just had another simple idea to try before throwing it out.

Perhaps the corroded batteries have expanded and are putting longitudal pressure on both end components making it impossible to unscrew. Aluminium threads are a bitch to undo when they bite - undoing my sump bolts are testimony to that theory and they often release suddenly once you crack it past their bite, but until then won't budge at all.

A quick thing to try is to bang the base of the torch flat on the workbench a couple of times - just hard enough to imagine squashing an expanded battery back a millimeter or two. Then try unscrewing from either end.


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Old 21st May 2020, 17:50
  #49 (permalink)  
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Thanks for all the suggestions. Most were tried. In the end it looked like a mangled piece of Swiss cheese and I came nowhere near accessing the battery compartment. It has now definitely been chucked out.
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Old 21st May 2020, 18:33
  #50 (permalink)  
 
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Preventative Maintenance

For aluminum barrel, aluminum end cap flashlights: When I buy one new, I apply a thin film of 'Ox Guard' to the threads. Intended for aluminum wiring to aluminum lugs in panelboards, it keeps the threads from galling. It also improves conductivity. Needless to say, once the batteries leak and corrode, it is often the end of the appliance anyway. I've opened flashlights where the batteries swelling made it impossible to extract them.
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Old 21st May 2020, 19:08
  #51 (permalink)  
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Alternate plan:

Grind away the entire end cap that you can't remove, but do it so carefully that you do not damage the threads.

View it as an archeological dig.

[Short of that, as previously suggested, grind two parallel flat surfaces so you can use a spanner.]

Once the guts are exposed, do whatever mechanical surgery is required to restore it to a functional state.

Then find the nearest hobbyist that possesses a 3D printer capable of making metal parts (okay, plastic in a pinch), and have them print you a new end cap for the flashlight.

Then, voila! A new light shines upon the world!
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Old 21st May 2020, 19:13
  #52 (permalink)  
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Alternate to alternate plan:

Forget about unscrewing it and cut off the end with a hacksaw.

Save what you can of the innards and make it work again.

Cut a new set off threads on the outside and cap it, or rig up some other waterproof solution that lets you change the batteries as needed.

Does the solution need to be elegant?

And, next time, take the batteries out before you let it sit on a shelf another few decades.
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Old 21st May 2020, 19:18
  #53 (permalink)  
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RIP LEDLENSER



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Old 21st May 2020, 20:05
  #54 (permalink)  
 
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Originally Posted by double_barrel View Post
It has now definitely been chucked out.
Did you manage to get the dustbin lid off?
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Old 21st May 2020, 20:24
  #55 (permalink)  
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Originally Posted by hiflymk3 View Post
Did you manage to get the dustbin lid off?


very droll......
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Old 21st May 2020, 21:17
  #56 (permalink)  
 
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I bet the OP is looking for a plastic dustbin and plastic top.

hifly wasn't being droll. It was hilarious.
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Old 23rd May 2020, 08:34
  #57 (permalink)  
 
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@ double barrel; please post a photo of the deceased so we can all pay our respects.

@ Ancient Observer, yes, absolutely. One of the jobs I occasionally do pays 30/hr, so I could have bought about 6 brand new LED Mini Maglites for the time it took me to repair one old one. But where's the fun and challenge in that? Fixing stuff successfully is good for the soul

@EEngr, that's a great tip, thanks ! I will try copper-slip, since I have no Al grease.
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Old 24th May 2020, 05:05
  #58 (permalink)  
 
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Fixing stuff successfully is good for the soul
After a long time as an engineer, I tried selling, I was worse than useless and in my business the sales cycle could easily amount to three years. Living with the fear of rejection for so long even when I was finally successful, brought me to the edge of sanity.

At least with engineering I could achieve a "success bump" within a couple of hours and if it went longer than a couple of days, someone would be along to say "It's not worth it, sling it in the bin"

IG

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Old 24th May 2020, 12:51
  #59 (permalink)  
 
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A friend of mine with an Imperial PhD in Physics/Maths/Movement does a lot of "selling" . He's just an acknowledged expert in his field. So the customers come to him. I suspect that if he took up "selling" he would fail - very noisily, but fail.
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Old 24th May 2020, 13:27
  #60 (permalink)  
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Originally Posted by Uplinker View Post
@ double barrel; please post a photo of the deceased so we can all pay our respects.
Sorry. It's gone!

Originally Posted by Uplinker View Post
Fixing stuff successfully is good for the soul
Absolutely. One of the reasons I was driven to save it was because it was a physically pleasing item, nicely engineered - albeit with one fundamental flaw! I just could not bring myself to chuck it out, whereas I get pleasure from throwing out cheap and nasty stuff, even if it was not cheap, if you see what I mean.
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