Odd Epee Maintenance

Discussion in 'Armory - Q&A' started by dshevy, Feb 20, 2012.

  1. dshevy

    dshevy Made the Cut

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    So i offered to do some armoury for my club and over the last few months have done quite a bit and learnt quite a bit.

    I have two epees, one re-wired by myself the other as wired from LP, both BF blades. The rewire is all LP parts, wire, barrel, tip, springs all of it.

    Now, the fencer who asked me to look at them said he came back from Doha with one not working and the other intermittent when the blade was bent. I've tested both with a standard test box and they are both fine, no sign of a short anywhere. I just tested them with a multimeter and they go from -1 ohms with nothing attached, stay at -1 ohms with the tip not depressed, to a steady 1.5/1.7 ohms then the point is depressed.

    For a very brief second sometimes, almost too quick to notice, the multimeter go to -20/-30ohms before going to the steady 1.7 but i checked and it does this with other weapon i know work.

    I haven't got a full epee box with timing chip to test but wondered if anyone had any idea why they may not have been working on piste, i have no reason to think this fencer was making it up?

    Thanks in Advance
    Shevy
     
  2. neevel

    neevel Armorer

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    Just to clarify, you did check for A-C and B-C shorts, right? If you just used a LED test box, you may want to check A-C and B-C with your multimeter- it may turn up evidence of intermittent shorts that you might not pick up with an LED box. Anything less than full open circuit or megaOhm range resistances in A-C and B-C indicates a problem that might not be picked up by the LED test box and gently depressing the point by hand. I'm a proponent of doing any testing other than quick, at-tournament weight/shim tests with a meter because you can gain a lot of information from seeing the actual ohm value of the line.

    You may have an issue with damaged insulation in one or both of the wires inside the point, right below the plastic contact cup. A gentle hand test of the point won't prevent a touch from registering, but a full-force hit can compress things enough to briefly create a short.

    The contact spring might also be set so that it only barely reaches the contacts. Fully depressing the point and holding it down by hand can get it to close the circuit, but touches while fencing that don't arrive "just so" may not.

    Another standard bit of advice would be to check the body cord(s) that the fencer was using, as well.
     
  3. Purple Fencer

    Purple Fencer Podium

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    The contacts on the wires themselves may not be level as well. Get a 3.5mm flat headed punch, insert into the barrel, lay against the contacts, and tap GENTLY with something (hammer, test weight...even a wrench will do) a few times, then check your tip and shim...you might find (after any needed adjustment) that the light fires more reliably now that the contacts are level.

    When I wire an epee blade, using that punch is now a standard part of my procedure...sets the cup AND levels the contacts at the same time.
     
  4. dshevy

    dshevy Made the Cut

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    I did A-C and B-C tests and there is no short. I got full open circuit with -1ohm readings just like when the multimeter has nothing attached. The contact is perfectly set to pass shim but only just so its not a contact issue .
     
  5. Mergs

    Mergs Podium

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    Well, first of all, you need to zero your ohmmeter. You can't get negative resistance. Second clean both the contacts in the barrel and sockets. Your readings of 2.5/2.7 (which is the range of -1 to 1.5/1.7 in your OP) is a tad high (should be 2 or less), which may be an indictor.

    Both Neevel and Sam have given you an excellent starting point.

    And welcome to our side of the asylum!
     
  6. Mr Epee

    Mr Epee Rookie

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    Rewire. Just do it.

    We're talking a few dollars in parts and a few minutes of work.

    I know there are likely alternative solutions available and I'm all for academic curiosity, but there's no point to shoe the king's fleetest messenger horse with the least rusty or least bent old nail.
     
  7. neevel

    neevel Armorer

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    I think he's using a digital meter- many models will use -1.0 to indicate a fully open circuit.
     
  8. Mergs

    Mergs Podium

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    So, what's wrong with 0?!??? It's probably the only really good thing to come out of ...... oops better not say it, want to PC you know.
     
  9. Purple Fencer

    Purple Fencer Podium

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    Nice almost-save, Colonel!

    Or, as we'd say in the USAF..."EJECT! EJECT! EJECT!!"
     
  10. K O'N

    K O'N Podium

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    I think 0 is already in use to indicate very low resistance. Using it to also indicate very high resistance would cause confusion, eh?

    K O'N
     
  11. Mergs

    Mergs Podium

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    Meh, maybe.

    Can you tell I don't use digital meters very much? ;)
     
  12. brtech

    brtech Podium

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    I've never seen a digital meter use -1 for "too many to measure" ohms. Usually, it's either ---- or 1888 or 1999

    Mergs doesn't use digital meters because he can't count that high.

    Of course, analog meters are usually preferred for armory work anyways, which is why we let him on our side of the table.
     
  13. neevel

    neevel Armorer

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    I've seen it. A digital meter I own shows 0.L on its 7-segment display (I presume standing for "Open Line").
     
  14. neevel

    neevel Armorer

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    Well, go back a ways and there's also this whole "Live in one place and plant seeds in the ground" thing, which is pretty important because Agriculture --> Grains --> Beer & Whisky!
     

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