Foil weapon failure testing...

[NotIndPk]

Hi:

This happened this past weekend:

- a foil was constantly going off target;
- everything ESLE was fine: so the barrel was opened and it was determined that the flange/washer/whatsis at the bottom of the tip may have descended and would be causing the foil to go off;
- the whatsis was hammered back in (- without comparing against a good tip - it was just assumed) and the foil "worked fine" ;
- two fencers used that weapon and both at some point lost to fencers they have never lost to (fence them regularly et al 0-5 losses in three bouts!!!!!);
- both fencers were attritbuting the lack of "lights" on bad point control;
- the same fencer had plates break off three times in past couple of months - an unusual occurence to say the least;

It was discovered that the metal plate on top of the foil wire had broken free and that the weapon's "touchability" become sporadic since sometimes the contact would be complete and sometimes it would not.

The reason we believe that metal plate had been broken-off all day was because of the "sporadic" nature of the touches recorded. After a 'failed touch' it would test properly as well as pass weight test.....

While we have no way of knowing exactly when the plate broke off- here is the question (thank you for your patient reading):

Can you test for this particular failure without opening up the barrel ? What equipment would you use and how?

(As an aside - the fencers have been appropriately "yelled" at to have a little more confidence in their point control and not assume that it was bad control that was causing a "miss")

[SJCFU#2]

Originally Posted by NotIndPk

Can you test for this particular failure without opening up the barrel ? What equipment would you use and how?

You could try hooking up the foil to a tester capable of detecting micro breaks (one with four lights, such as a Favero), and slowly flexing the blade, watching the tester for any sign of a break (indicated by one of the yellow lights coming on). You can also try beating the blade against something (I usually use the side of my foot), watching to see if there are any indications of a break. Ideally there should be none, but if there are then it means there is some sort of a problem.

Unfortunately all of this will only tell you that there is a problem, not necessarily where it is located.

[NotIndPk]

Originally Posted by SJCFU#2

Unfortunately all of this will only tell you that there is a problem, not necessarily where it is located.

.....but, the fencer can then switch to a different weapon, as opposed to what they did.......one of them actually did realize that something was wrong but in the round robin he was actually out of the running by then......

[brtech]

Tips with the contact at the end of the post coming off or getting loose is a known failure, but its fairly rare. Just pounding it down won't work. The swage that hold it in place is not holding on. Tip replacement is the solution.

You are suggesting that the contact in the cup is separating from the wire. That happens sometimes. It's hard to make a definative diagnosis of that kind of problem.

You can usually see this kind of problem with a Favero tester with the intermittent lights. You wack the weapon on the edge of a table and it blinks the yellow lights. Now, any foil will do this if you wack it hard enough, and describing "how hard" is pretty tough.

Did you try cleaning the barrel and the tip? Often the symptom you describe can be caused by a dirty point. Next, make sure the spring is seating in the cup correctly. Finally, change the tip and the spring. Next, make sure the barrel is on tight. This also causes intermittent connections.

Usually, if the problem can be narrowed to the tip, and you have changed the spring and tip to eliminate them, then the only thing you can do is rewire.

[Purple Fencer]

This is more of a problem than you think. it sounds like the little flange where the spring contacts the tip assembly came loose. If it IS loose, it could break the circuit, which would fire the off target light.

They're pressure-fit onto the post and over time and use can get loose.

This can be fixed by doing something the maker probably did not do...swage the post.

Take the tip out of the barrel and place it face down on something firm (like the head of a vise)....the post and flange should be facing UP. Get a small center punch, place it on the end of the post, and hammer it firmly a few times...this will deform the very end of the post and hold the flange on firmly. This will usually solve this particular problem.

I see this pretty often...sometimes the tip flies out and the fencer never nows, because teh screw, spring, and collar are still in the barrel, thus keeping the circuit closed.

As for identifying the problem....usually you have to take teh tip out and look at the end. here are some things to look for.

1) The end of the post of the tip should be flush with the edge of the flange...if the post is down inside the flange, it'll be loose. Tap it down gently and swage the tip.

2) The flange ma be flush with the post....but if it's loose, it'll be a problem....swage it.

3) There could be some corrosion built up where the spring sits. Go to a hobby store and pick up a short length of brass tubing. The inside diameter should be just enough to fit around the tip of the flange...outside dia should not be so big that the tube can't fit easily into a barrel. You don;t need a ver long length...3 inches is fine. Rough up the end a touch...then spin that end over the end of the flange to scrape away any corrosion. You can also stick it in the barrel and do the same to the end of the wire.

You CAN initially ID the problem from the outside if you know what to look for....but you'll still have to take teh tip apart to actually fix it.

1) if the space between the bottom of the tip itself and the top of the barrel look too large, the flange may be starting to come apart. Take it out, tap it back into place and swage.

2) If the tip feels like it spins TOO freely, the flange may be starting to come apart. Take it out, tap it back into place and swage.

Good luck!

[rsy]

Originally Posted by NotIndPk

It was discovered that the metal plate on top of the foil wire had broken free and that the weapon's "touchability" become sporadic since sometimes the contact would be complete and sometimes it would not.
* * *
Can you test for this particular failure without opening up the barrel ? What equipment would you use and how?

This type of problem is often caused by a barrel which was has become loose and then re-tightened. Between loosening, re-tightening and the movement in between while the weapon is being used, it is not uncommon to fatigue the wire enough to cause it to break right at the cap. The 4-light Favero is a great way to test quicky to see if that is the problem. But if you have more time, try this:

Remove the tip and spring and soak the barrel and the first inch or so of the blade in acetone. After the glue has softened up, pull gently on the wire to see if it will separate from the tip. If it it comes free, then you know that was the problem. If it doesn't, then it isn't. In that case, wait until the acetone evaporates, re-glue the wire, clean out the tip with a cotton swap soaked in acetone and try something else.

-r