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Archive-name: sports/skating/ice/rec-skate/blades
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Recreational Figure Skating FAQ
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5. Blades
Blades are commonly made in 1/4 inch lengths. Blades also have different
widths and radii, as well as different configurations of the "bulge"
(spinning area) and toe picks. These all have major effects on the way a
blade "feels". A list of commonly available blades and their characteristics
and prices is given in Appendix 1.
Figure skate blades start out in three separate parts. TOE plate. HEEL plate
and the part that actually does the work on the ice. These are punched out
on large presses. The blades are blanked out of long strips of steel which
vary in Carbon content depending on the quality of the particular skate
blade that is being made.(i.e. a Majestic would have a lower grade of steel
than say a Phantom or Pattern 99 Although the steel used for all blades
hardens to the same standard, the better grade would keep its edge
longer(under equal conditions).
Before the three parts are put together to make the skate the blade section
is hardened. This is done in large quantities hung on a frame and lowered
into a high temperature salt bath for a set period of time to be evenly
heated and while still glowing red are quenched in an oil bath. The shock of
the sudden decrease in temperature causes the steel to harden . However, the
hardness at this stage is too brittle, so the blades (still on the frame)
are put into another salt bath of a lower temperature to temper to about
what is called 60 degrees on the Rockwell scale. When cooled they are
removed from the frames fed into a machine that grinds them to a set
thickness.
The toe and heel plates (already ground) are then brazed to the blade. There
are two methods of joining the parts together. John Wilson products are all
silver soldered. This is a fairly low temperature braze achieved by
electrical coil induction which causes the heat from the brazing to travel
down onto the blade reducing the hardness to about 40 degrees Rockwell 'C'
for about halfway but leaving the lower "working" half (about 5/16'') still
at 60 degrees. Mitchell & King on the other hand silver solder theirs but
the top quality blades such as Phantom, Gold Star etc. are hand brazed with
bronze. This operation creates a lot more heat therefore the blades, by no
means soft could be a bit patchy in their hardness. They are then set into
an induction coil, electrically heated, rehardened and tempered about
halfway up the blade.
You can tell if your blades are hand brazed. If you look at them you will
notice that where the toe and heel plate joins the blade there is a very
large radius. This method is very strong. Silver soldered skates will have a
small bead of braze so the radius will be much smaller. However silver
solder flows well and fills gaps readily. So, whichever method is used there
will still be 5/16'' or more of correct hardness.
The assembled blade is now chrome plated, the profile is ground on and the
chrome is removed from the edges by grinding. This is the line that you see
each side of the blade edge. This is removed so that hardened steel and not
chrome is at the working surface. There is of course extensive polishing and
inspection before shipping.
5.1 Buying new blades
The blade length denotes the measurement from the front of the sole plate to
the back of the heel plate. Measure the length of the sole from toe to heel
and fit blades which are 1/4 inch less in length.
Some people believe that they have to buy blades that are super expensive in
order for them to become great skaters. You should buy well-built and
*appropriate* equipment. Skaters gradually upgrade their equipment as their
needs change, for example a skater may need to upgrade skates when they move
from basic skating to their first jumps or from double to triple jumps.
Advanced blades require the skater to perfect his/her technique.
Top of the line blades are designed for very advanced skaters. Advanced
free-style blades have a longer radius and have *large* toe picks. Also, the
portion of the blade that is used for spinning is much shorter than on
intermediate blades; that means that unless you are perfectly balanced and
positioned going into and during the spin you will start rocking on the
blade. Intermediate blades like the MK Professional, Coronation Ace, etc.
provide you more "room" to make corrections and continue spinning even if
you are slightly off balance.
Just because the MK Gold Stars are typically over $400 does not mean that
they are inherently better blades than MK Pros or Phantoms. Starting with MK
Pro and Coronation Ace lines, the blades are all made using much the same
materials and manufacturing process as described above. To put it
succinctly, certain blades are more expensive simply because of supply and
demand and a few slight design modifications like side honing which makes
them marginally more costly to produce.
5.2 Three ways of checking used blades:
1. Look at how thick the dull strip is on the sides of the blades along the
edges. They were three or four millimeters when new. If they're now thin,
then your blade has been sharpened many times. The concern here is that the
rocker may be distorted after many sharpenings, and it is almost impossible
to restore without specialized equipment.
2. Put the skate upright on a table, and check the position of the bottom
toepick. The blade should also be touching the table within one or two
inches of the toe pick. If the blade touches the table further back, it
means that the toe-pick is too low (probably a consequence of successive
sharpenings). If the blades touches closer than 1 inch, the master toe-pick
may have been ground off. In this case, the blades will be useless for
learning spins and jumps.
3. Ask the skate sharpener at your rink to examine the blade. They can tell
you if the blade is bent, incorrectly mounted or obviously damaged by abuse
or bad sharpening.
If the only problem is that the toe pick is too low, ask your shop to grind
it some to raise it. Never have the bottom (master) tooth ground off your
blades unless you only intend to use them for figures. Otherwise the tooth
fairy will never forgive you!!
5.3 Mounting
Skates with improperly mounted blades can be virtually impossible to skate
on. The blade must be correctly positioned and aligned on the boot. To avoid
twisting the blade, the boot heel and sole contours must match the blade
mounting surfaces. If not, the surfaces can be trimmed with a rasp, or shims
can be added between the blade and boot.
Briefly, this is how your skate shop will mount the blades:
1)find the center of the tip of the sole and the center of the heel and draw
a line joining them.
2) place the front of the sole plate of the skate blade in line of the front
of the sole of the boot, and maintain the skate blade along the line drawn.
This will place the blade between the big toe and first toe.
3) Screws may be placed only in the slotted holes, so that you can try them
and make minor adjustments (a blade position slightly closer to the big toe
is sometimes favored). Don't do any jumps until the best position of the
blades has been found and more screws have been inserted.
5.3.1 Problems with warping
1. The blade may have shifted sideways slightly when the front or back pair
of screws were tightened on the temp mounts, warping the blade from front to
back.
2. The holes for the permanent mounts might not be positioned perfectly,
warping the blade as in #1 above.
3. The heel might not be perfectly level or flat with respect to the front
of the boot. Old screw-holes may have created bumps on the heel. Or the boot
might have been manufactured with an uneven heel. Such a heel will twist the
blade.
5.3.2 Checking for mounting problems
If you have trouble getting good edges, first have the blades checked to
make sure they are straight, properly sharpened and mounted perpendicular to
the sole. If the problem persists, have someone watch to see if your blades
"make snow" as you try to skate on the edge in question. If they do, this
may point to a mounting problem which can be corrected by a slight shift of
the blade mounting. You will need to tell the person remounting your blades
which edges you are having trouble with.
You can also check if your blades are mounted correctly by yourself (you
need recently sharpened blades for this test to ensure that the edges are
even):
1. Find a clean patch of ice
2. Gather some speed and glide on two feet on a straight line. Keep your
body upright. Your feet should be directly under your hips. Try this
several times, both backwards and forwards
3. Go back and look at the the traces: if the blades are set correctly you
should get a set of double lines for each foot. If one of the lines is
consistently thicker than its mate (or if there is only one line), it
means that your weight on that blade falls predominantly on the edge
tracing that line,i.e., the blade is unbalanced.
4. If you are leaning mainly on the inside edge, have the blade shifted to
the inside and vice versa. You probably only need a small shift -try
moving it by 1 or 2mm and then repeat the test
5.4 Rocker
Rocker is the curve of the blade from toe to heel, and is based on the arc
of a circle with a given radius. Thus, if you drew a circle with a 7 foot
radius and placed a blade with a 7 foot rocker along the inside curve of the
circle, it would line up with the tracing, at least at the rear (tail) of
the blade. The curve at the front, behind the toe pick is somewhat sharper.
It is this difference of curvature which allows you to turn and spin on the
front of the blade.
The smaller the radius, the more rocker (amount of back and forth rocking
motion you can get when standing on the blade) it has. With small radius
blades, you can do turns with less chance of falling as there is less blade
on the ice. For the beginner, a 6' radius is fine as, among other things, it
is very forgiving in the toe pick department -- you really need to lean way
forward on them to catch the picks.
The bigger the radius, the flatter the blade. This will generate more speed
as more of the blade contacts the ice. You will want a flatter blade (7 foot
or more) as you become more advanced. When you start learning jumps, you
will find that you need good edge control. Because you have more blade on
the ice, you can start to prepare your body position for takeoff without
falling off the edge so easily.
5.5 Grind or hollow
Hollow or grind refers to the concave surface on the bottom of a correctly
ground blade. A small radius creates edges that will dig deeply into the
ice, while a larger radius digs in less, but glides more freely. A hollow
with a 5/8'' to 3/4'' radius is recommended for beginners and "all purpose"
skates. This hollow will allow you to sense how a proper edge should feel,
and at the same time be forgiving in things like T-stops. The weight of the
skater will also affect how deeply it should be ground: Usually children
will need a deeper hollow than fully grown adults.
Finally, the width of the blade is yet another factor to consider: A deep
hollow with a 3/8'' or smaller radius will be UNFORGIVING on freestyle
blades, unless you are a child or have a very petite frame. This type of
grind may yields crisp and fast 3-turns, ability to hold a very deep edge
when landing jumps, and allows for fast spins IF you have them centered. An
uncentered spin on deep edges will cause you to travel. See about traveling.
On the other hand, such a small radius will be ideal for dance or hockey
blades: Because these blades are narrower than freestyle blades, the need a
deeper grind to get the same grip on the ice.
A shallow "figure" hollow with a 1'' or larger radius will require a more
correct lean to prevent skidding and requires more frequent sharpening, but
yields an easy glide and clean tracings.
5.6 Advanced blade features
5.6.1 K-pick
The K-pick design consists in a set of extra 3-4 picks to the side of the
standard toe-picks. This feature is supposed to provide more control and
better anchorage to the ice on toe-jumps. According to blade manufactures,
the jump height can increase by 5-10% and the jump length by about 20% on
toe loops and flips. No significant improvements in height and length have
been reported for the Lutz, although the improved stability on the take-off
supposedly makes for more consistent jumps. Many freestyle blades models,
particularly at the high end range, are available with K-picks.
5.6.2 Side honed, parabolic and tapered blades
Most skating blades have the same constant width along its full length.
However, some advanced freestyle figure skating blades have a concave
section ("side honing"). Side honed blades are thicker at the stanchions and
the edge stripe and thinner in between. You can tell side honed blades
because reflections appear inverted.
Another modification to the edge profile found in advanced blades is
"tapering". Tapered blades are thicker at the front near the toepicks and
thinner at the tail, i.e. the edges are not parallel. Parabolic blades are
thinner in the middle section and thicker at both ends. Some models or
custom made blades can be both side-honed and tapered.
These modifications make the blade lighter (because of the removed steel)
and supposedly provide a better grip on the ice. Not surprisingly, the more
laborious manufacturing process translates in a higher price. Whether they
actually provide any real advantage is a matter of discussion.
5.7 Sharpening explained by an expert
Take your skates to a pro shop or ask some regular skaters at your rink
where they get theirs sharpened. Skate sharpening is NOT a do-it-yourself
project! Skates are expensive and it only takes one bad sharpening to turn
them into scrap metal!
1) You have to know and trust your sharpener,
2) Your sharpener has to know you and your needs,
3) You have to stand guard over your skates until they are sharpened by the
proper person.
Skates properly sharpened will have a smooth concave grind accurately
centered along the length of the blades, edges squared (parallel to the
bottom of the boot) and level with each other (inside edge at same height as
outside edge) for the length of the blade. Proper sharpening will maintain
the correct rocker for the life of the blade.
Freestyle sharpenings will have typically a 1/2'' radius concave grind and
will be in a sharp condition. The edges of a deep freestyle grind have the
great advantage of holding jump landings on hard or soft ice and also will
outlast a shallow grind by a considerable amount of time. They will also
hold landings on missed jumps and give the skater that extra split second to
catch their balance and avoid unnecessary falls. A sharp deep grind takes a
little effort on the part of the skater to adapt but is well worth the
effort and once adapted to it will be no problem in future sharpenings.
Figure sharpenings will have 1 1/4'' radius concave grind and will be in a
medium sharp condition. The figure grinds are extremely smooth and flow
freely on the ice. More shallow (greater radius) grinds have extreme flow on
the ice but are usually suitable only for the more advanced skater.
Combination sharpenings will have 3/4'' radius concave grind and will be in
a medium sharp condition so that the skater can skate figures with ease or
they can be used for general skating. The grind will be of smooth finish and
will flow quite freely on the figures (although not as freely as a true
figure grind). This grind can be used for all jumps and spins and will hold
well while blades are in a sharp condition. This grind is also very suitable
for occasional skaters and some dancers; and is also good for adults to
start with.
Skates should be resharpened before they become so dull that you begin to
slip on hard ice (eg: not flooded since last night). This will also minimize
the adjustment you need to make to your newly sharpened skates. Nicks in the
blades should also be attended to. Bad nicks in the edges will ruin the
finest sharpenings.
When the blade is ground down a long way after many sharpenings, the
relationship between the bottom pick and the blade edge should be maintained
by removal of steel from the pick. There should be about 1/2'' lift at the
heel before the pick makes contact with the ice. Just because your blades
are ground down past the line of chrome plating, that is not an indication
that you need new ones. There is still lots of life left as long as the
sharpener replaces that "line" and adjusts the pick height.
Beware of how some shops do their sharpening: Some shops flat-grind the
blade first, and then hollow grind. This wears the blade at an accelerated
rate.
5.8 Maintenance
There are two kinds of blade covers, hard rubber/plastic guards and
terry-cloth "soakers". The plastic guards should be worn *any time* you step
off the ice. Even "safe" rubber mats or carpets accumulate dirt and grit
from the shoes of pedestrians, and this grit will nick and round off the
fine edges of your blades much faster than gliding across the ice. Do not
leave them on your skates between sessions as they will trap water and cause
your blades to rust.
The cloth soakers are put on after you have removed your skates and wiped
them dry with a rag. They protect your blades from bumping in transit and
wick away any condensation so your blades won't rust. If you still have
problems with rust or want to store your skates, rub a drop of oil or
Vaseline along the bottoms of the blades.
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Recreational Figure Skating FAQ - Blades
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