resistance problem in epee?

[milstdfarm]

I have a couple of epees that won't fire (plus the grounded light lights on scoring machine). But if I plug the body cord directly into scoring machine the epee works correctly.

I can plug other epees into the same combination of scoring machine, floor cord, spool, and body cord and they work correctly.

I assume that means the resistance in the epee itself is too high. Am I right? How do I fix this?

Thanks!!

[shlepzig]

It sounds like you have a short in your epee somewhere. The amount of problem you may have with this depends on

I would be interested in hearing from more experienced armourers in the field on this one. My experience has been that some machines are more sensitive to this problem than others. My candid observation has been that Favero machines are particularly sensitive to any kind of short to ground in epee causing the touch not to register while others are not.

Some years ago I competed in a tournament in which I later found I had an observable intermittent short in my epee (R = 200 ohm ish, later found to be a return spring lightly contacting the outside edge of the barrel). On the SG machines where I practice, this was not a problem (no grounding light). During the tournament (which was exclusively run Favero Machines) the grounding light was intermittent and many solid touches did not set off the light, resulting in a very frustrating day.

Before rewiring these epees (with new points, the offending points were at the time a new screwless point I was using and I felt this issue was inherent in their design) I tried the weapons with the SG machines at the club, and had no problems (e.g. it appeared that the short was not new).

Recently at another tournament (also using Favero scoring machines) I observed many instances of apparent touches not scoring (in my own bouts and in other fencers bouts). I happened to notice the yellow grounding light on or intermittently blinking on the scoring boxes. In my own case, I observed in warmup that when I would throw a flick the yellow light would flash and the touch might not register when the tip depression felt solid. Again hardly a scientific example since flicks are not a 100% shot when thrown well, and the other observations are just candid observations.

Have the experienced armourers on the board noticed a particular succeptibility of different machines to grounding out of epee touches with shorts to ground with high resistance? What suggestions do you have for weapons setup that minimizes this possibility.

[SJCFU#2]

I would definitely start by looking for an internal short in the epee (either A-to-C or B-to-C). Minimum resistance between either A or B and C should be somewhere in the megaohm range.

Regarding scoring machines, Eigertek and SG machines will register a touch even when a zero-ohm internal short exist in an epee (either A-to-C or B-to-C), but Favero, LP and Tripplette machines will not. To a large extent this stems from the way scoring machines evolved. Analog machines (which were pretty much the norm up through the 80's and even into the 90's) often had a common ground bus that connected the C lines from both fencer as well as the strip. Since they all connected to a common bus there was no way for the machine to distinguish between a touch which landed on a grounded strip, the opponent's guard, or a short inside the weapon itself. Fortunately just about all of those old machines are now obsolete for anything other than epee, so you aren't likely to see many of them. Unfortunately the requirement for a common ground lingered long after these machines had become obsolete (IIRC it even used to be included in the rules). This led some designers to program their machines to block touches when an epee has an internal short to ground even though the machines was perfectly capable of distinguishing between an internal short and a hit to the opponent's guard.

What I've always found ironic is that for many years the FIE used SG machines for their major events, despite the fact that they did not conform to this particular requirement.