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Armory is the art and science of fixing fencing equipment.
[edit] The Armorer
The experts in the field. You will see them at national tournament checking equipment and ensuring that all the strips are working. These are hardworking beings who run on a complex mix of beer and circuitry.
[edit] Fencer's Toolkit
This is from the epee/foil point of view and uses some information from http://www.fencing.net/forums/thread6637.html.
[edit] What Every Fencer Must Have
As an athlete, you are responsible for your own equipment. It is essential that foilists and epeeists have at least the following items in their portable toolkits, although sabre fencers can often get away with a great deal less:
- Tightening tool (inside hex, outside hex, or screwdriver, but stick to one and keep all your equipment the same)
- Jeweler's screwdriver for tip screws
- Flathead screwdriver for body cords and sockets (a Gerber or Leatherman works well)
- Needle nose pliers
- Open End wrenches (metric, a 7mm and a 6mm)
- Adjustable (sometimes called Crescent) wrench
- Razor blade
- Superglue
- Tester box
- Small parts, particularly screws, springs, tips, nuts, and washers
- Tip tape (foil)
[edit] Next Step
- Fine sandpaper
- Coarse sandpaper
- Shims and weight
- Larger parts, including bell guard, bell pad, and sockets
- Lighter (controversial)
[edit] Home Armory
- Workbench
- Vice
- Rewire equipment:
- Wires
- Blade bender
- Tip plunger
- Acetone or Dremel tool
- Glue
- Analog ohm meter
- Hacksaw or lock cutter
- Metal file
- Soldering iron
- Threading tool
[edit] Weapon Specific Help
An electric épée has a special electric tip attached to the end of the blade. The tip serves as a switch, indicating when a touch has landed.
Electric épée uses a normally-open circuit, where current from the scoring machine can flow through one contact of the guard socket and down one of the two wires to the tip, but cannot return to the scoring machine unless the tip is pressed in, shorting the two contacts at the ends of the wires together, which allows current to flow back through the other wire, the second contact of the guard socket and back to the scoring machine. Assuming the scoring machine doesn't also detect current flowing through a ground circuit it will register a touch, and since there is no off-target in épée any touch is assumed to be a valid touch. The only exception would be a touch on a grounded surface (a grounded strip, the opponent's guard, or in some cases the fencer's own guard), in which case the scoring machine will ignore the touch entirely.
The electric épée tip is a complex assembly, typically consisting of a metal/plastic composite tip, two springs, two screws, two contacts set in a plastic base and a metal barrel, all of which must be fit together correctly.
The barrel screws onto the threaded end of the blade (4.0 mm thread). The plastic base with its two metal contacts sits inside at the bottom of the barrel. The larger of the two springs (also known as the weight spring) sits atop the plastic base and seeks to push the tip out of the barrel. The two screws pass through slots in the side of the barrel and into the tip, keeping it from being pushed out of the barrel (screwless tips use a collar that screws onto the end of a specially threaded barrel in place of the screws). The smaller spring (also known as the contact spring) screws onto a small threaded post at the base of the tip, where it can short the two metal contacts together when the tip is pressed down, closing the circuit and cause the scoring machine to register a touch.
In order for an electric épée to score a touch the tip is to be pressed in with at least 7.36 Newtons of force and travel at least one millimeter. These are tested by placing first placing a 750 gram weight atop the tip and ensuring that the scoring machine does not register a touch, making sure that a 1.5 mm shim can fit into the gap between the tip and the barrel, then making sure that the scoring machine does not register a touch when the tip is pressed down with a 0.5 mm shim fit into the gap between the tip and the barrel.
One of the most common failures in épée is travel. Usually this is due to the contact spring being too long, shorting the contacts together before the tip has been pushed in at least 1 mm. Travel can be adjusted by altering the length of the contact spring, usually by screwing the spring down onto the threaded post.
Another common failure in épée is that touches fail to register when the tip is pressed in. This can be due to a number of causes, including a contact spring that is either too short or skewed too far off center to short the two contacts together, a break in either wire anywhere along the length of the blade, a pinched wire where it passes through the guard and socket, or a faulty body cord, reel or floor cord. The only way to detect one of these faults is by noting that touches are not registering. This is one reason why many épéeist routinely test their weapons after every halt.
Épées rarely fail weight test, however when they due it is usually a sign that the weight spring is too weak to support the 750 gram weight. The weight spring should either be stretched, which may temporarily solve the problem, or replaced.
Other potential problems include a short between on of the wires and the blade (which can prevent touches from registering on some scoring machines), a loose barrel or pommel or a broken blade.
An electric foil has a special electric tip attached to the end of the blade. The tip serves as a switch, indicating when a touch has landed.
Electric foil uses a normally-closed circuit, where current from the scoring machine can flow through one contact of the guard socket, down the wire to the tip, then back through the blade to the second contact of the guard socket and back to the scoring machine. Pressing in the tip of the electric foil breaks this circuit, interrupting the current flow. The scoring machine interprets any break in this current flow as a potential hit.
If the tip is in contact with the opponent’s lame then current will flow through the tip, into the lame and back to the scoring machine. If the scoring machine detects a break in the normally-closed circuit at the same time it detects current flowing through the opponent’s lame then it interprets this to indicate a valid touch.
If the scoring machine detects current flowing through a ground circuit, such as a grounded strip or the opponent’s bell guard at the time the normally-closed circuit is broken then it will ignore the touch. The one exception would be if current were also flowing through the opponent’s lame, such might occur if the opponent were to pull their arm back far enough for their guard to touch the lame, in which case the scoring machine would register a valid touch.
If the scoring machine detects a break in the normally-closed circuit and no other current flow then it assumes that this indicates a touch landed off-target and indicates an invalid touch.
The electric foil tip is a complex assembly, typically consisting of a metal/plastic composite tip, a spring, two screws, a contact set in a plastic cup and a metal barrel, all of which must be fit together correctly in order to work properly.
The barrel screws onto the threaded end of the blade (3.5 mm thread). The plastic cup which houses a metal contact sits inside at the bottom of the barrel. A spring sits atop the contact and seeks to push the tip out of the barrel. The two screws pass through holes in the side of the barrel and keep the tip from being pushed out of the barrel.
There are at least three widely used types of foil point, commonly referred to as the French, German, and British. All are slightly different in how they approach the screws and how they retain the tip. There are also screwless foil tips that rely on a collar that attaches to the end of a specially threaded barrel to retain the tip, rather than screws.
French-style foil tips have a metal collar ring that fits around the narrow waist of the tip. Two holes are drilled into this ring and threaded to receive the tip screws. The tip screws hold this ring in place inside the barrel. When fully assembled, the spring pushes the flange at the base of the tip against the ring, allowing current to flow from the wire from the socket, through the contact and spring to the tip, then through the ring to the tip screws, barrel blade and back to socket. Pressing the tip in breaks contact between the flange and the ring, interrupting the flow of current.
German-style foil tips have a metal collar ring similar to the French style, however there are no holes in the ring for the screws. Instead the holes in the barrel are threaded to receive the tip screws, which then extend through the barrel and clamp onto the ring, holding it in place.
British-style foil tips discard the collar ring entirely, relying instead on the flange at the base of the tip to press directly against the tip screws extending though the barrel.
In order for an electric foil to score a touch the tip is to be pressed in 4.9 Newtons of force before the tip moves. This is tested by placing first placing a 500 gram weight atop the tip and ensuring that the scoring machine does not register a touch. There is no minimum travel requirement for foil however there is a maximum travel requirement of 1.0 mm, which can be tested by making sure that a 1.0 mm shim can not fit into the gap between the tip and the barrel.
Possibly the most common failure in foil is intermittent white-lights. These occur whenever there is break in current flow, which the scoring machine interprets to indicate a touch. The circuit will be broken whenever the tip is pressed in, however it can also be broken by a break in the wire, a poor connection between the wire and the contact, dirt insulating the contact from the spring or the tip from the collar ring (or tip screws), a loose barrel, a loose grip, a poor connection between the body cord, a bad reel or a bad floor cord. Unfortunately the scoring machine has no idea where the current flow was interrupted so any momentary break registers as a touch. Many of these problems can be addressed simply by making sure that everything is tight (threaded connections tend to work their way loose over time) and clean (it is amazing how much dirt and grime can collect inside a tip).
The other common failure in foil is the weight test. If the foil is unable to support a 500 gram weight then it is a sign that the spring is too weak and should be stretched, which may temporarily solve the problem, or replaced.
When the tip is in contact with the lame, it is possible for the lame to form a short between the tip and the barrel, providing an alternate path for current to travel through the normally-closed circuit. In this instance, the scoring machine will not register a touch because the current flow will not be interrupted. The first 15 cm of the foil blade (including the side of the barrel) are supposed to be insulated to prevent this from happening however the tape used for insulation can easily be damaged. The insulation should be inspected regularly and replaced when worn.
It sometimes helps to apply the tap in two pieces. The first covers the blade and possibly the base of the barrel. The second wraps around the barrel, covering the screw. That way only the second piece of tape will need to be removed in order to gain access to the tip screws.
Other potential problems include a broken wire (in which the scoring machine will register a continuous invalid touch), short between the wire and the blade (in which case no touches will register and a broken blade.
Troubleshooting Steps:
On the Strip:
These actions should be taken by the DIRECTOR when a foil
starts to act flakey on a strip. In the event that an issue
occurs during the bout, the Fencer SHOULD NOT ATTEMPT to
diagnose the problem themselves as this can annul any right
to appeal of a missed point by that fencer due to faulty
equipment.
1) For intermittent or constant off target signals
*Always work from Back to Front*
A) Start at the connection between the Body Cord and
the Floor Cord
B) Expose (but do not remove) the prongs of the body
cord at the body cord/reel cord junction.
C) Using a screwdriver or similar chunk of metal (A
largish coin may work also), connect the A and B
lines.
i) If this stops the off target signal, take a
spare body cord and connect the weapon and the
Reel cord. If there are no more off target
lights, have the fencer swap out body cords.
ii) If the off target light continues to go off
this may be an issue with either the Reel or
the floor cord.
D) Check the plug for the following
i) poor contact between the body cord plug and the
weapon socket
ii) Visibly loose or broken wires between the
socket and the weapon wire
E) Check under the bell guard pad fo make sure that
the wire has not been 'smooshed' under the handle
and that it is not broken there.
F) Check at the bell guard for broken wire at the
juncture of the bell guard and the blade. Often
the wire will be frayed or broken as it goes into
the "spaghetti" insulation, or the insulation will
not extend outside of the bellguard allowing for
the wire to break.
G) Check along the length of the blade grove for 'popped'
wire and visible breaks
H) Check to make sure that the barrel is tightly attached
to the blade. If loose attempt to tighten the
connection using two wrenches. One for the Barrel and
one for the blade. DO NOT OVER TIGHTEN! A simple
'snugging' of the barrel to the blade is all that
should be required. over tightening can cause the
barrel to split, the threading to strip, or the blade
to be snapped off!
I) Twist the plunger at the end of the weapon to see if it
is a 'dirty' connection between the internal spring
and the plunger assembly.
2) For a failure to register hits, there is usually a grounding between the weapon and the wire, either in the barrel, at the bellguard or along the length of the blade. Often this is caused by a loose barrel that has been tightened onto the blade wire or the handle being compressed onto the wire causing a short between the handle/bellguard and the wire inside the ‘spaghetti’ insulation.
Sabre is the simplest of the electric weapons to maintain because there is no electric point or wire to worry about. There is only a blade, guard, socket, pad, grip and a pommel that helps to hold everything together.
Electric sabre uses a normally closed circuit in which current enters the weapon through one side of the socket then returns to the machine via the other. Often the two contacts of the socket are shorted together to ensure resistance less than 1 ohm. Should current flow be interrupted then the scoring machine will indicate a fault with a white light. White lights in electric saber may be caused by a poor connection between the body cord and socket, a loose connection within the socket, a loose pommel, or a bad body cord, reel or floor cord.
Should the blade come in contact with the opponent's mask or lame then current will flow through the blade to the opponent's lame and back to the machine and the scoring machine will indicate a valid touch.
The interior of the sabre guard should be insulated in order to prevent current from traveling from the saber and the fencer's own lame, which would effectively turn the blade and guard into an extension of the target area. The pommel and portion of the guard closest to the pommel should be insulated for the same reason. The most common form of insulation on the inside of a guard is paint. A plastic cover or tape may be used to insulate the pommel and adjacent 8-10 cm of the guard.
Most electric sabre repairs consist of identifying and replacing the faulty component. The most common repair is probably replacing a broken blade. This is accomplished by unscrewing the pommel, removing the broken blade, inserting a new blade and screwing the pommel back on. Any insulation that was removed or damaged when removing the pommel should then be reinstalled or replaced.
[edit] Piste Equipment
For additional help, please refer to fencing.net's [Armory Q&A].
