Epee tip problem

[wbowman]

I've been having a problem with an epee tip that I'd like to invite some theorizing on. I suspect this will eventually be a re-wire job, but I'm looking for any ideas short of that.

It's a fairly new German tip, mounted on a Prieur FIE blade. Worked fine for a while and then quit working in the middle of a practice bout.
When I tested for continuity THROUGH the depressed tip, I got current through one wire, but not the other (the one in the middle -- is that the "B" line? Never can remember).
So I took the tip apart, tested again for continuity and got it through BOTH wires. The contact spring looked okay. Not bent or anything, so I put the tip back together and it looked fine.

THEN, it failed again (this time in a tournament bout). Took it home, repeated the same series of tests with the same results. Just to be sure, I changed the contact spring, put it together and it worked fine.

Okay, so I took it to the next tournament. It worked for a while, and then failed once more.

At this point, I've decided that I don't trust it, so I should re-wire it just to get a fresh start. But I'm also curious about what might be going on here.
Anybody got any ideas?

[fencerbill]

Probably wire broken right behind the cup that keeps making and then breaking - needs rewiring if so.

Remote possibility: Incomplete removal of shellac from the wires at the socket. Although as long as you have been fencing, that is unlikely.

Crud in tip? Migrating in and out of contacts.

[DHCJr]

Another possibility is the contacts themselves and how well you set your travel spring.

Look in the barrel at the relative heights of the contacts. If there is a significant difference, what you described could happen. After a while you would only be hitting one.

If this is the case, try pushing down the higher one to even them out.

Second, on setting your travel spring. If you just use some Epee shims you may have set it at 0.49 or 0.04. If the latter, any solid hit would probably cause your weapon to stop working.

Using automotive shims, adjust the travel to between 0.35 and 0.45mm would be best.

[KD5MDK]

Unless I'm mistaking you, how will an epee with travel set between .35 and .45mm pass the thin shim?

[DHCJr]

Originally Posted by KD5MDK

Unless I'm mistaking you, how will an epee with travel set between .35 and .45mm pass the thin shim?

The thin shim is 0.5mm (+/- 0.05mm). What it tests is the Epee does not go off with it there. What this means if the travel was set at 0.45. i.e. The Epee will go off when it is 0.45mm from being completely depressed. If the travel was set at 0.55, it would fail any legal shim.

I hope this made it clearer.

[KD5MDK]

Ahh. I had mentally reversed it and was somehow thinking it was "Must travel at least .5mm" Which it is in a way, given the thick shim.

[DHCJr]

M.19.4, it must travel at least 1mm. Many times I've had to reread a rule several times before I understood them. The FIE doesn't make things easy.

[Fechter1]

Originally Posted by wbowman

I've been having a problem with an epee tip that I'd like to invite some theorizing on. I suspect this will eventually be a re-wire job, but I'm looking for any ideas short of that.

Possible sources of the problem:

1- contact spring not making proper contact. This can actually have two causes, off-tilt spring or residue on the actual contacts. As you've written, the spring is seated properly (side note: is it long enough to make consistent contact?). You need to make physical contact with both contacts inside the barrel, best with a small screwdriver. If that works consistently, it's the spring. Easiest to fix.

2- Wire break in the barrel, most likely right at the cup where the wire meets the contact. Somewhat elusive to test for. Short the contacts inside the barrel (again with small screwdriver) and rotate the cup VERY GENTLY, if possible, keeping the rest of the weapon absolutely still. If the circuit is intermittent, then you've located the problem. Definitely needs rewire.

3- Wire break along the blade. Visual inspection should suffice here. Obiously needs a rewire in that case.

4- Wire broken/caught at the base of the handle (where the wire passes through the guard). Visual test plus conductivity test while applying stress to the handle/guard should suffice. Also check for B-C shorts under pressure. Most likely needs a rewire, depending on the severity of the fault.

5- Intermittent contact between wire and socket. Uhlmann wires have that sneaky second layer of insulation. This is the coppery sheen that you see when you remove the blue cloth (?) oute insulation. You need to remove this (my favorite method is sandpaper) until you get the silvery sheen. Reconnect wire to clip and retest conductivity.

6- Intermittent contactbetween socket and body cord. Test with ohmmeter (or other continuity tester) while keeping point depressed and manipulating body cord. Intermittent circuit => body cord problem. Multiple ways to improve contact here (spit on the prong, widening the prong, ensuring good connection between cord wire and prong, cleaning the clip, etc).

Anhything beyond this is no longer a weapon problem.

That's about as comprehensive a guide as I can think of right now. If anyone has any additional possible points of failure within the weapon, please let me know.

Hope it helped.

[KD5MDK]

As you've written, the spring is seeded properly

What's its classification? Is it on a points list?

[wbowman]

Thanks everyone. I suspect it's still going to be a re-wire job (for the sake of trusting it if nothing else), but you've given me a few more things to try first.