My epee scoes on opponent's guard -- and it's my fault. Reasons ASAP?

[ysbadadden]

OK, I can cover my epee tip with Scotch tape. Then it will score when it hits my opponent's guard. [Beside the point: I can be really clever and cover only half the tip, so that the weapon will NOT short on my opponent's guard except when I want it to. This has been done.] But my question is this: What else--besides insulating the tip with Scotch tape or something -- will make my epee short out on my opponent's guard?

(The epee shorted on opponent's guard, body cord "C" line, floor cable "C" line, and back end of floor cable "C" line entering the machine. When fencers were reversed, the problem reversed. It was solved by changing weapons.)

I need to know because I have a batch of epees to fix over the weekend. Thanks!

[Purple Fencer]

It's not that the point is shorting out on teh guard....it's that it's NOT shorting out.


Hitting the guard transfers the electrical power from your tip, into your opponent's guard, into their C line, and out to ground. (same a hitting the guard in the other weapons)

If your tip is insulated by anything that blocks that power (and it doesn't take much), power will go up one of your wires and down the other, closing your circuit and firing your light.

[ysbadadden]

For example, dirt inside the tip? So I can simply clean it out?

[Purple Fencer]

Originally Posted by ysbadadden

For example, dirt inside the tip? So I can simply clean it out?

Cleaning the tip out would be good regardless...a q-tip with a quick dip in rubbing alcohol does the trick...and a blast with an air cannister to dry it out quickly.

However, dirt in an epee tip tends to inhibit smooth motion of the tip, no fire the light (unless it's something like graphite or plating flaking off the tip or inside of the barrel)

Sufficient dirt in the tip may block contact between the spring and teh ends of the wire so the light DOESN'T fire...but that's not hte problem you;re describing.

Check the C socket on the other guy's epee....if it's not tight, it won't make the connection to teh bracket. also, on the C socket there's usually a small metal tab that goes from the receiving socket to teh bracket (on Leon Paul epee sockets, that connection is more direct...the nut that hilds teh plastic body to teh bracket is in direct contact)...so any thing loose may break that connection.

[Mergs]

If it was only one particular guard that was being hit, it could also be corrosion on the guard or someone may have reassembled it wrong and put the pad between the socket and the guard.

[brtech]

You said it "shorted" on the body cord C. By this, did you mean that if you touch your epee to his body cord C, and depress the tip, you DO get a light?

If that is the case, then it really must be your weapon.

To diagnose this, I would use a test box or multimeter set up so I could see connections. I would verify that from B or C, with the tip depressed, that I had connectivity from the tip surface. With a multimeter set to ohms, connect to B or C on one lead, the surface of the tip with the other lead and depress. You should see a connection. If you don't, remove the tip. Check to see that you have connectivity between the small spring (contact spring) and the tip surface. The most common problem is crud or something on the tip, but it could be a bad tip, or some problem between the contact spring and the tip thread.

[noodle]

Originally Posted by ysbadadden

OK, I can cover my epee tip with Scotch tape. Then it will score when it hits my opponent's guard. [Beside the point: I can be really clever and cover only half the tip, so that the weapon will NOT short on my opponent's guard except when I want it to. This has been done.] But my question is this: What else--besides insulating the tip with Scotch tape or something -- will make my epee short out on my opponent's guard?

(The epee shorted on opponent's guard, body cord "C" line, floor cable "C" line, and back end of floor cable "C" line entering the machine. When fencers were reversed, the problem reversed. It was solved by changing weapons.)

I need to know because I have a batch of epees to fix over the weekend. Thanks!

manifest cheating. black card.

if there's not any stuff on the surface of your tip, and your weapon is definitely consistently doing it, you have only a few, very unlikely choices. your contact spring is corroded or your tip is corroded, both of which are so unlikely that it looks more like cheating.

in addition, theoretically, if you're fencing on an old machine without a grounding pin on the plug and you're fencing on carpet in this cold weather, it might be possible to build up static enough to cause a problem.

point is, its almost definitely not you, it is almost definitely your opponent. test differently in different scenarios. if you're still sure you're the problem, follow these steps, fully testing after each one and only proceeding to the next one if the one before doesn't work:
1) test other weapons to verify it is only that weapon causing problems. switch back. verify.
2) get your opponent to switch weapons to verify its not their weapon. switch back. verify
3) make sure there's not any crap on your tip and that you and your opponent are electrically grounded.
4) both you and your opponent try new body cords, reel, floor cord, and machine if possible. one at a time, if possible. cheapest next step.
5) put in a new contact spring.
6) put in a new point.
7) rewire your blade.
8) its definitely your opponent.

[tdwg83]

Originally Posted by ysbadadden

OK, I can cover my epee tip with Scotch tape. Then it will score when it hits my opponent's guard. [Beside the point: I can be really clever and cover only half the tip, so that the weapon will NOT short on my opponent's guard except when I want it to. This has been done.] But my question is this: What else--besides insulating the tip with Scotch tape or something -- will make my epee short out on my opponent's guard?

(The epee shorted on opponent's guard, body cord "C" line, floor cable "C" line, and back end of floor cable "C" line entering the machine. When fencers were reversed, the problem reversed. It was solved by changing weapons.)

I need to know because I have a batch of epees to fix over the weekend. Thanks!

I'm confussed. Was there tape on your tip or not? Or is it a guess of how it could be your fault?

[Gav]

This thread illustrates how important it is to have a basic understanding of how the scoring electronics work.

Noodle's post is one of the best illustrating why the fault is unlikely to be ysbadden's.

I have to confess to being a bit mystified as to why it was the OP's fault...

[parrythis]

In order for a hit to the opponent's bell guard to be detected, two surfaces must have good conductivity:

1. Your opponent's bell guard
2. The surface of your weapon's tip

If you are certain that the problem is with your weapon, try cleaning/polishing the surface of the tip. If that doesn't solve the problem, try changing the tip.

If the problem was in the internal workings of your tip, none of your touches would register.

[noodle]

Originally Posted by parrythis

In order for a hit to the opponent's bell guard to be detected, two surfaces must have good conductivity:

1. Your opponent's bell guard
2. The surface of your weapon's tip

If you are certain that the problem is with your weapon, try cleaning/polishing the surface of the tip. If that doesn't solve the problem, try changing the tip.

If the problem was in the internal workings of your tip, none of your touches would register.

incorrect as stated. "in order for a hit to the opponent's bell guard to be detected in a low/no-speed/impact testing environment" is more correct. you can register valid hits in epee on bell guards without any malfunction from either side's equipment. its really hard to do, but its doable.

[tdwg83]

Originally Posted by noodle

incorrect as stated. "in order for a hit to the opponent's bell guard to be detected in a low/no-speed/impact testing environment" is more correct. you can register valid hits in epee on bell guards without any malfunction from either side's equipment. its really hard to do, but its doable.

How? By hitting so fast that the type is still depressed when coming away from the guard?...more confusion

[mrbiggs]

I don't know how much you know about armory, so I'll start fairly basic. There are two poles inside the barrel. When the tip is depressed, a small spring on the end of the tip connects the two poles. But the tip is connected electronically to the spring, and the machine detects if the tip is touching the barrel (because the electricity travels down your opponent's C line rather than down the other wire on your blade.)

So basically, these are your options:

1. Somehow, the spring is connecting the two poles without touching them. I have no idea how this would happen, but I suppose it's a possibility.
2. The spring has become electronically disconnected from the tip, or the tip does not conduct electricity from one side to the other. I've actually heard of this happening due to weird cracks in the metal. Epee tips have an insulated part, so it's possible for the tip to remain whole while the electrical part is cracked.
3. There's something insulating between your tip and your opponent's guard. This is the scotch tape cheating method you mentioned earlier. Corrosion can build on a tip; you might try lightly sanding it. Usually a visual inspection will make it clear if this is a problem, though.
4. There's something wrong with another piece of equipment and a series of coincidences are leading you to believe that it's your blade. I would actually say that this is about as likely as 1 or 2, so I would suggest that you isolate the problem using an ohmmeter. (Put one end on the A or B line of your epee's socket (the ones that are closer together), the other on your tip. Depress it and make sure that the electricity is flowing).

There might be a few problems I missed, like noodle's static electricity problem, but this is a place to start. I'd also suggest changing out the tip and seeing if the problem continues. (I'm almost certain it won't).

Originally Posted by noodle

manifest cheating. black card.

I'm not a rules expert, but calling this "manifest" cheating seems extreme to me. Even as an amateur armorer, I've seen some very unlikely problems with equipment, some of which were clearly advantageous to one of the fencers. Manifest cheating implies evidence that cheating actually occurred, and this problem can be caused by a number of factors. If it looks suspicious, a group 3 red for "intentional modification of equipment" wouldn't be out of place.

[noodle]

Originally Posted by mrbiggs

I'm not a rules expert, but calling this "manifest" cheating seems extreme to me. Even as an amateur armorer, I've seen some very unlikely problems with equipment, some of which were clearly advantageous to one of the fencers. Manifest cheating implies evidence that cheating actually occurred, and this problem can be caused by a number of factors. If it looks suspicious, a group 3 red for "intentional modification of equipment" wouldn't be out of place.

that was meant to be more tongue-in-cheek.

[WickedWitch]

It sounds like a problem my daughter had once. The bell guard may not be grounding due to corrosion, or a problem with the body cord socket.

[griffindm]

This sounds like a problem in the referee's diagnosis, not in your equipment. If the ref merely had the two fencers swap ends, and the problem persisted, they are not checking the problem properly.

The proper method to track down this particular problem on the strip is:

1) disconnect the weapon on the side whose bell is registering the hit
2) test the other weapon's tips against the C line (the prong furthest from the other two)
3) if the problem is repeatable, disconnect the body cord from the reel on the same side and test the tip against the reel connector for line C (be careful not to get a false positive from the insulating plastic around the socket)
4) if the problem persists, go back to the floor cord that connects to that reel, and test the tip against the C line of that floor cord.

This process catches and isolates 99.99% of the problems of this type. The remaining possibilities are a machine failure, manifest cheating with the weapon whose tip is registering the touch, or oxidation on the tip of the weapon, which may also be manifest cheating under the correct conditions.

Did your ref try any of these steps?

The problem with reversing the fencers is it does not pickup the possibility that the fencer with the questionable bell may have loose connection between his body cord and the weapon socket.

[DangerMouse]

The one other option if the tip is going off as you pull it away is that the contact spring is sticking to contacts.

[tdwg83]

I see. So just in need of tip cleaning in that case.

[DangerMouse]

Generally it needs a contact spring replacement in that case, not just cleaning.

[ReMO9119]

Instead of cheating, you could, you know, hit them on target.