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An engineering challenge for you

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An engineering challenge for you

Old 17th May 2020, 21:28
  #21 (permalink)  
 
Join Date: Sep 2006
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I have a small, newish LED Lenser. The end cap in that requires quite a sustained heavy torque (by hand) to get it open, so I imagine a corroded one might be impossible.
i'd be looking for a strap wrench, as others have suggested.

Last edited by Blues&twos; 18th May 2020 at 19:26.
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Old 17th May 2020, 21:47
  #22 (permalink)  
 
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Originally Posted by Black Sun View Post
It's likely that thebattery has leaked and caused internal Corrosion.
I would try a few heating cycles with a heat gun interspersed with soaking the end in a cup of diesel, it will move eventually
That's exactly what happened to mine.
Plenty of penetrating fluid, pliers and a vice finally got it open, even after cleaning everything it never worked properly again. I ended up replacing the battery holder/switch part to get it working again.
You can buy the battery holder/switch part separately.
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Old 17th May 2020, 21:54
  #23 (permalink)  
 
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Originally Posted by treadigraph View Post
Generally I find if I spend hours trying to take something apart to mend it, once it's in bits I find it's totally stuffed anyway. Or I break it in the process...
Agreed, if it's been sitting for years, it's nearly 100% probability that the batteries have leaked and destroyed the interior bits.
I had a Maglite that happened to - getting it apart wasn't bad, but the internals were so corroded that hours of attempted repairs were completely wasted and it ended up in the trash.
Yea, those quality flashlights are expensive, but your time also has value.
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Old 18th May 2020, 09:56
  #24 (permalink)  
 
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I brought this old soldier back from the dead, after the old batteries leaked and corroded and jammed in the barrel. I managed to get the end cap off after submerging the cap end in a cup of penetrating oil for a few days, and filling a flat to accept a spanner. Then I drilled into the batteries and used progressively larger screws to grip them and try to pull them out. I put the torch through a hole in the deck of my workbench, and used some large rubber cable clamps around the torch to protect it, while using a lever to pull out the screw. After many attempts I got both batteries out.

But then disaster - the penetrating fluid had stripped the silvering off the reflector ! My solution was to mould a plaster plug into the reflector and use that to push in some aluminium foil against it. This worked very well. The foil is not smooth, so you don't get a strong focused spot in the beam but instead a nice uniform wash of light, which is actually much better to use.

I found a really nice LED bulb replacement on line, cleaned all the internals with contact cleaner and the old soldier is back on duty - upgraded and with a few battle scars.


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Old 18th May 2020, 10:36
  #25 (permalink)  
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Last year my aunt gave me a number of things to keep or dispose of if they were useless including an old torch/roadside hazard light that had belonged to my uncle, probably 40+ years old. Astonishingly, the old half brick sized EverReady battery inside still held charge and it all worked! I've no doubt the battery was newer than the torch but not that much! Not something I want to carry around with me but kind of handy in the house if the leccy goes down.
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Old 18th May 2020, 11:42
  #26 (permalink)  
 
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I got told off by a Belgium line checker when I used my P7 for the walk round instead of the company issued Ever Ready brick. The P7 had about 5 times the illumination.
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Old 18th May 2020, 15:43
  #27 (permalink)  
 
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Originally Posted by tdracer View Post
Agreed, if it's been sitting for years, it's nearly 100% probability that the batteries have leaked and destroyed the interior bits.
I had a Maglite that happened to - getting it apart wasn't bad, but the internals were so corroded that hours of attempted repairs were completely wasted and it ended up in the trash.
Yea, those quality flashlights are expensive, but your time also has value.
Agreed,
We should upgrade to lithium batteries like the early B787. Then when the batteries go bad they will self-extract from their enclosures
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Old 18th May 2020, 15:51
  #28 (permalink)  

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That's undeserved!
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Old 18th May 2020, 18:58
  #29 (permalink)  
 
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Originally Posted by lomapaseo View Post
Agreed,
We should upgrade to lithium batteries like the early B787. Then when the batteries go bad they will self-extract from their enclosures

Now that's funny!
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Old 19th May 2020, 16:07
  #30 (permalink)  
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I tried dipping the end cap into liquid nitrogen. The video shows it to be a plug fit within the tube so shrinking it should free it up. Some back of a beer mat sums suggest that, assuming no heat flow between cap and body, the differential temperature should open-up up a gap of nearly 2mm.

It had no perceptible effect. So sadly I am resigned to binning it. Although it is a thing of beauty, there can be no doubt that the inside must be corroded beyond repair.
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Old 19th May 2020, 16:35
  #31 (permalink)  
 
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Originally Posted by double_barrel View Post
I do have access to liquid nitrogen that might usefully shrink the end piece. The video above shows that I need to shrink the end not expand it! It's a plug that fits inside the tube.

(I also have access to monkeys...)
A Sqn of Air Cadets can often achieve the same result and are easier to locate!

If you lock an Air Cadet and a 25lb Cannonball in a sealed room with no windows, then return 10 minutes later - at least 1 will be broken!
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Old 19th May 2020, 18:23
  #32 (permalink)  
 
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Originally Posted by double_barrel View Post
I tried dipping the end cap into liquid nitrogen. The video shows it to be a plug fit within the tube so shrinking it should free it up. Some back of a beer mat sums suggest that, assuming no heat flow between cap and body, the differential temperature should open-up up a gap of nearly 2mm.

It had no perceptible effect. So sadly I am resigned to binning it. Although it is a thing of beauty, there can be no doubt that the inside must be corroded beyond repair.
It wouldn't, because the barrel would have shrunk by the same amount, since it is obviously in very tight contact with the end cap.

If all else fails, drill a small hole in the centre of the end cap. Stand the torch up in penetrating fluid and leave it for a week, ensuring that the corroded thread stays submerged in the fluid. The hole should allow the penetrating fluid into the inside and work into the thread from there.

Then try again. A vice might hold the end cap, but if not, file some flats on it, like I did and use a spanner. The torch body appears to have a flat on the side which. might accept another spanner?

Good luck. If all else fails, a new P17 only costs 90, (but I know that is not the point).


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Old 20th May 2020, 11:18
  #33 (permalink)  
 
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Engineers cap on.

Find a stick of hardwood at some handy length and hammer two nails through one end spaced less than the diamater of the end cap apart to create an F tool.
Using your F tool make some marks on the end cap and drill holes.
Inset F tool into holes and rotate stick to unscrew the end cap.
If stick breaks throw the whole lot in the bin.

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Old 20th May 2020, 13:46
  #34 (permalink)  
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Won't help double_barrel any, but I finally got my ceiling rose cover loose a little earlier and the main body is now firmly fixed to a beam as it should have been before.The method? Brute force... There is a loose connection... and I fixed that too.
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Old 20th May 2020, 15:41
  #35 (permalink)  
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Originally Posted by cattletruck View Post
Engineers cap on.

Find a stick of hardwood at some handy length and hammer two nails through one end spaced less than the diamater of the end cap apart to create an F tool.
Using your F tool make some marks on the end cap and drill holes.
Inset F tool into holes and rotate stick to unscrew the end cap.
If stick breaks throw the whole lot in the bin.
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.
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Old 20th May 2020, 15:47
  #36 (permalink)  
 
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How many ppruners does it take to fix a torch?
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Old 20th May 2020, 16:40
  #37 (permalink)  
 
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If everything fails, hand torch to old school merchant ship engineer.
A long time ago, I had a mega motoring disaster. it could not even be classified as a challenge to me. Sat on the kerb at the side of the road, head in hands, thinking "what can I possibly do now", then a nice man came along and fixed it even better than new.

I have great respect for old-school marine engineers. One day we will meet again and I will thank him again.

IG

Last edited by Imagegear; 21st May 2020 at 17:58.
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Old 20th May 2020, 16:41
  #38 (permalink)  
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Originally Posted by hiflymk3 View Post
How many ppruners does it take to fix a torch?
I don't know yet.
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Old 20th May 2020, 21:56
  #39 (permalink)  
 
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Only just occurred to me that the one thing that double-barrel can't do is start the thread of the appliance.
Why then is he labelled 'Thread Starter'???
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Old 21st May 2020, 06:23
  #40 (permalink)  
 
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Smile

Originally Posted by jimtherev View Post
Only just occurred to me that the one thing that double-barrel can't do is start the thread of the appliance.
Why then is he labelled 'Thread Starter'???
Made me laugh.
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