PK Design Lab
Results 1 to 21 of 21

Thread: Maglite O ring sizes

  1. #1

    Default Maglite O ring sizes

    Hi all, totally new to the forum, it's looks full of information to help with my first divelight project.
    I've had a bit of a trawl through but can't seem to find O ring upgrading information for maglites. I need to find out all the inner diameter o ring sizes of a D cell maglite and the suggested thicknesses to help waterproof the tailcap and bezel for diving purposes, hope someone can share this info. I'm in UK so metric sizes would be gratefully appreciated. Thanks.

  2. #2

    Default Re: Maglite O ring sizes

    The sizes were mentionned in a post of packhorse on another forum which seem to be offline.
    IIRC, the o-rings at the lens should both be 48x2mm, the o-ring in the tailcap 32x2.54mm or something like that (not really sure about that last one). Maybe 350xfire or packhorse can confirm this?

  3. #3
    Flashaholic* Klem's Avatar
    Join Date
    Mar 2010
    Location
    Perth Australia
    Posts
    581

    Default Re: Maglite O ring sizes

    I use a 2.5mm thick one at the back. Same ID as the factory O ring...Works fine.

    I don't use O rings at the front. I use a bead of silicone sealant (Silastic or similar) Rationale being, you only need one access port to the torch for regular battery charging. Any 'servicing' needed on the head/LEDs you can crack the silicone and clean-up the residual flakes with a wire brush reasonably easily. Epoxy putty fixes the lens permanently to the bezel, and silicone to seal the lens to the head (semi permanent).

    If it is a wand you are building with no need to regularly open then you could do away with all the O rings. Seal the back up with silicone sealant as well. Up to you, and personal preference.
    Last edited by Klem; 03-13-2011 at 11:26 PM.

  4. #4

    Default Re: Maglite O ring sizes

    Appreciate the help and quick replies.
    I'm actually going to be using the 5 x D cell maglite as a cannister for an umbilical (it'll act as a counter weight for my pony cylinder, lol), the lens is now a solid piece of aluminium with a cable gland in the middle, so I'll probably seal it up permanently shut, just hope I can reach round far enough to access the switch once it's been fully waterproofed. Will let you know how things go.

  5. #5
    Flashaholic* Klem's Avatar
    Join Date
    Mar 2010
    Location
    Perth Australia
    Posts
    581

    Default Re: Maglite O ring sizes

    Sounds good!

    Like the idea of using the Maglite as a canister.

    Two quick thoughts;
    1. If you're concerned about the location of the canister and effort needed to switch on/off you could shift the switch to your wand.

    2. If you're thinking of 'permanently' sealing the canister I take it you will be charging via the wand down the umbilical? In your shoes I'd use at least one O ring on the canister. That way you can easily service/swap the batteries and let the canister air out.

    My early experience with sealed battery canisters is that the connections and wiring eventually corrodes (probably due to the trapped humidity condensing after the first dive).

  6. #6
    Flashaholic* 350xfire's Avatar
    Join Date
    Aug 2008
    Location
    Texas
    Posts
    1,229

    Default Re: Maglite O ring sizes

    48mm IDx 2mm thick for head
    #124 tail cap

  7. #7

    Default Re: Maglite O ring sizes

    Quote Originally Posted by 350xfire View Post
    48mm IDx 2mm thick for head
    #124 tail cap
    is this for a "D" or a "C" mag ?

  8. #8
    *Flashaholic* wquiles's Avatar
    Join Date
    Jan 2005
    Location
    Texas, USA, Earth
    Posts
    8,392

    Default Re: Maglite O ring sizes

    Quote Originally Posted by FEtochini View Post
    is this for a "D" or a "C" mag ?
    The lens side of the head is identical for the "D" and "C".
    Please no PM/Visitor Msg's. Email for questions/Paypal: wquiles [at] gmail {dot} com. Please visit my new website.

  9. #9

    Default Re: Maglite O ring sizes

    but not the tail cap ...

  10. #10
    Flashaholic* Klem's Avatar
    Join Date
    Mar 2010
    Location
    Perth Australia
    Posts
    581

    Default Re: Maglite O ring sizes

    Quote Originally Posted by FEtochini View Post
    but not the tail cap ...
    I use 32mm (inside diameter) * 2.5mm thick for the tailcaps of D Cell Maglites.

    Sourced them on EBay for a few dollars.

    I don't have a C Cell so don't know, however if you measure the ID of the factory supplied one and go 2.5mm that will work.
    Last edited by Klem; 03-18-2011 at 06:05 PM.

  11. #11
    Flashaholic* 350xfire's Avatar
    Join Date
    Aug 2008
    Location
    Texas
    Posts
    1,229

    Default Re: Maglite O ring sizes

    D Maglite = 124 for tail cap

  12. #12

    Default Re: Maglite O ring sizes

    Thanks again, I've now got two, 2mm x 48mm ID O-rings and one, 2.5mm x 32mm ID O-ring on order for my D cell mod, coming from a UK supplier at £1.20 each which is quite expensive over here but if it works it will be well worth it.
    Just one more question for you, when using a 2.5mm x 32mm o-ring for the tailcap does the o-ring dissappear into the shaft like the original or does it squash between the tailcap and shaft and is still visible from outside when tightened up ? Just wondering as I tried it with a 2.5mm x 34mm ID and you could still see it, maybe just that bit too big. I also had trouble with it earthing without the tailcap touching the shaft but will perhaps take a bit of anodising off the threads if it plays up in future. Thanks.

  13. #13
    Flashaholic* 350xfire's Avatar
    Join Date
    Aug 2008
    Location
    Texas
    Posts
    1,229

    Default Re: Maglite O ring sizes

    2.5mm may be too big... don;t know though.

  14. #14
    Flashaholic* Klem's Avatar
    Join Date
    Mar 2010
    Location
    Perth Australia
    Posts
    581

    Default Re: Maglite O ring sizes

    2.5mm on the tailcap squashes under the body when you do it up. It's a tight fit but with silicone grease it does up nice and waterproof.

    Electrical path is as factory designed.

  15. #15
    Enlightened
    Join Date
    Apr 2011
    Location
    Greece
    Posts
    31

    Default Re: Maglite O ring sizes

    Hi All

    Can anyone please tell me the size of a maglite C size tail cap

    Thanks
    Dimitris

  16. #16
    Flashaholic* 350xfire's Avatar
    Join Date
    Aug 2008
    Location
    Texas
    Posts
    1,229

    Default Re: Maglite O ring sizes

    I tried to get a good oring a while back and could not get the proper one. Why not just JB Weld in place and feed wires through cable gland hole?
    http://tlslights.com/ your source for quality affordable dive lights, Mag-lite conversions and weapon lights. Now a Federal Firearms Dealer.

  17. #17
    Flashaholic* DIWdiver's Avatar
    Join Date
    Jan 2010
    Location
    Connecticut, USA
    Posts
    1,527

    Default Re: Maglite O ring sizes

    I just measured my light, and the tailcap has an OD of 1.000" where the O-ring sits, and the body has 1.125" ID. This is a perfect fit for a -022 size o-ring. Any competent supplier should have them.

    I bought a bunch of o-rings at AOP Technologies. They are cheap but have a minimum order. If you only want a few, maybe you want to search on where to buy o-rings. I'm sure there was a discussion about it here somewhere. It's even possible that your local hardware store will have it. It would be specified with "nominal" sizes of: Inner Diameter (ID) = 1", OD = 1-1/8", thickness = 1/16", though the actual spec is ID=0.989", T=0.070".

    Since this is such a good fit, and since MAG products are made in the US and would use standard parts wherever possible, I think it's safe to say the light was properly designed with this o-ring in mind, and you will get a very reliable seal at any diving depth with this o-ring in a MAG-C in good condition, provided you properly lubricate and maintain the seal.

    Oh, just saw you are in Greece. I don't know if the AS 568A sizes are standard there. If you can't find the correct o-ring or have to pay lots for it, post here and I'm sure someone will help you out.

  18. #18
    Flashaholic* 350xfire's Avatar
    Join Date
    Aug 2008
    Location
    Texas
    Posts
    1,229

    Default Re: Maglite O ring sizes

    DIW, I think I tried a 22, 23 and 24 and they were all just a bit too big. I think the 22 went in about 1/2 way and would not go in any more. It worked but you do see about 1/2 of it. Not a big issue. I'll look and see as I still have a few laying around. May be some brute force can get it in all the way.
    http://tlslights.com/ your source for quality affordable dive lights, Mag-lite conversions and weapon lights. Now a Federal Firearms Dealer.

  19. #19
    Flashaholic* DIWdiver's Avatar
    Join Date
    Jan 2010
    Location
    Connecticut, USA
    Posts
    1,527

    Default Re: Maglite O ring sizes

    If a -022 is too big, maybe try a -021?

    Edit:
    I just found the o-ring that came off my light (I was heating the tailcap with a torch to hot-melt a piezo element into it, so removed the o-ring to avoid burning it). It measures dead on the specs for a -022.
    Last edited by DIWdiver; 02-01-2012 at 06:43 PM.

  20. #20
    Flashaholic* 350xfire's Avatar
    Join Date
    Aug 2008
    Location
    Texas
    Posts
    1,229

    Default Re: Maglite O ring sizes

    But, will that oring seal for a dive light?
    http://tlslights.com/ your source for quality affordable dive lights, Mag-lite conversions and weapon lights. Now a Federal Firearms Dealer.

  21. #21
    Flashaholic* DIWdiver's Avatar
    Join Date
    Jan 2010
    Location
    Connecticut, USA
    Posts
    1,527

    Default Re: Maglite O ring sizes

    Quote Originally Posted by 350xfire View Post
    But, will that oring seal for a dive light?
    Hmm... The recommended stretch is 1-5%, and this application would stretch a 0.989" o-ring onto a 1.000" diameter, so that's 1.1%. A little thin, but within range.

    Squeeze should be around 30% for 'static' seals (parts don't move during use), and around 20% dynamic seals. The ID and OD of the light parts are 1.000 and 1.125, or radius of 0.500 and 0.5625. That's a difference of 0.0625, and the o-ring thickness is 0.070, so the squeeze is (0.070-0.0625)/0.070=0.0107. That's 10.7% squeeze. That's pretty thin.

    What does the o-ring get pushed up against when pressure is applied? On my light, threads are cut right through into the o-ring area, so the o-ring is pushed up against the cut threads. That's not good at all. On the other hand even rather deep diving depths of 300 FSW are only around 5% of the pressure that the o-ring could handle in a properly designed system. Also the parts don't move when pressure is applied, so at low pressures there is likely to be little or no damage to the o-ring.

    The next thicker ring in standard AS-568A sizes would be a -120. Stretch would be 1.3%, but since the thickness is 0.103", the squeeze would be 39%. That might make it difficult or impossible to close the light, could damage the o-ring during assembly, and it might degrade the lifetime of the o-ring (though replacing it once a year would be pretty reasonable).

    Maybe you could find a metric size that would match better. Apple Rubber has two sizes that would fit the recommendations, but it might take a lot of money to get a few of them.

    Bottom line: A light using the MAG-C parts and the stock -022 o-ring would probably be fine, but I wouldn't put a lot of trust in it. If I could close it with a -120 o-ring installed, I'd be happier. If I could get a metric or non-standard o-ring closer to the ideal 0.98" (24.9mm) ID and 0.0893" (2.27mm) thickness, I'd be much happier.

    D

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •