This article is from the Fencing FAQ, by Morgan Burke with numerous contributions by others.
Many fencers have experienced trouble mixing their points,
barrels, and wires. They are best used in matched sets. There
are many brands to consider, each with different qualities. Some
brands are cloned by Chinese and eastern manufacturers; you may
notice a difference in quality or durability when using
Points are regularly tested in competition. Both foil and epee
points must pass a weight test, by lifting a mass (500g for foil;
750g for epee) after the point is depressed. (Technically, epees
only have to lift the mass 0.5 mm, whereas foils must lift it to
the top of the point travel.) In addition, epees must pass two
shim tests, the first to make sure that there is at least 1.5 mm
of travel in the tip, and the second to make sure that the point
doesn't light until the last 0.5 mm.
If the weight test fails, the main spring can be replaced or made
heavier by lightly stretching it. If the fencer thinks his point
is too heavy, the spring can be replaced, compressed, cut down,
or softened by heating one end in a flame.
If the epee 0.5 mm shim test fails, the secondary contact spring
is too long. It should be adjusted or compressed. If the 1.5 mm
shim test fails, your point may be improperly set up, or may be
mismatched with the barrel.
Most points are held together by a pair of screws on the side of
the barrel, and adjusting the springs requires disassembly. Some
makes of epee point are adjusted using a small wrench or a single
screw in the tip. FIE epee points use a solid contact in place
of the secondary spring. Lighting distance can be increased by
carefully filing the contact.
Epee points work by closing the circuit between the two blade
wires when they are depressed. Dirty or faulty points will
normally cause the weapon to fail to register touches. Foil
points work in the opposite manner, by opening a closed circuit
between the blade wire and blade. Dirty or faulty points will
usually cause the weapon to produce spurious off-target lights.
See Troubleshooting (sections 2.15, 2.16), below.
Blade wires are typically insulated with cotton to facilitate
gluing and cleaning. Nevertheless, inexpensive wires can be made
at home using 26 to 36 guage wire-wrap or magnet wire from an
electronics store. Use the cup from an old wire, and attach the
new wire by heating the solder connection with a soldering
iron. This is more difficult with epee wires; the contacts may
have to be removed from the plastic base before soldering -
whether this is possible depends on the brand of wire. In a
pinch, with foils you can spool a bit of wire in the bottom of
the cup; this will work for a short period, but eventually the
spooled wire gets fouled with the spring and causes faults.
Blade tips are threaded metric 3.5 x 0.60 for foils and 4.0 x
0.70 for epees. Rethreading with a die is difficult, but
possible with adequate preparation. Pre-filing the tip into a
long, blunt cone (5.5 mm long with the top 1.5 mm narrower than
the inside diameter of the die) will assist in guiding the die
through the initial turns; the extra metal left behind can later
be removed with a file. The leading edge of the wire groove
should be rounded and the groove filled with epoxy putty or
similar hard compound to prevent the die from jamming on the
groove edge. The putty must be removed afterwards, of course.
No more than 4 mm of threading is needed to affix the barrel.