Skate Sharpening Explained: Hollows, Radius, and When to Sharpen

Picture the bottom of a hockey or figure blade right after a skate sharpening. It is not flat. A grinding wheel has just cut a shallow trough down the center of the steel.

Two thin edges stand up on either side of that trough, like the rails of a tiny sled. A deep hollow leaves two edges that are sharp and aggressive. A shallow hollow leaves two edges that are less pointed, so they hold their edge longer.

What radius of hollow actually changes

A shop technician calls the depth of that trough the radius of hollow, or ROH. It is measured as the radius, in inches, of the curve cut into the steel. A smaller number means a tighter, deeper cut.

A larger number means a flatter, shallower cut. According to Sparx Hockey, a shallower hollow trades bite for glide.

A deeper hollow trades glide for grip instead. Either way, the two rails left by that cut are the real cutting edges.

One edge faces the inside of the blade. The other faces the outside. A skater standing on flat ice balances on both at once.

Every stride, stop, and turn depends on how those two edges meet the ice. That is why the same skates can feel different after two different sharpenings.

How a shop actually cuts the hollow

A skate sharpening machine holds a spinning abrasive wheel above the blade. The wheel is shaped, or dressed, into a slight curve that matches the chosen radius. The blade passes under it in a series of light, even strokes.

Cutting fluid or water keeps the steel cool during the pass. A deburring stone then knocks off the tiny wire edge, called a burr, left behind by grinding. That last step is what makes a fresh edge safe to skate on right away.

Radius of hollow chart: hockey and figure skating

The numbers on a shop’s hollow chart are not arbitrary. A common shop hollow ladder runs from a deep half inch up to a shallow full inch. Most shops default to a half inch or five eighths inch unless a skater asks for something else.

Radius (hockey)	Typical skater	Feel on ice
1/2 inch	Youth and lighter or recreational skaters	Deepest common hollow, most bite, dulls fastest
5/8 inch	Senior and high school shop default	Standard grip most adults start on
3/4 inch	Many advanced and competitive skaters	Less bite, noticeably more glide
7/8 inch	Heavier skaters, softer ice	Shallow, fast, holds an edge longer
1 inch or more	Heaviest skaters, hardest ice	Shallowest common hollow, longest lasting edge

Sparx has published data from one NHL team. More than half of its players skate on five eighths inch or larger. Many sit at three quarters, seven eighths, or a full inch.

Shallower than the old default is common at the top level. It is not rare at all.

Figure skating runs its own ladder. It does not line up neatly with the hockey numbers. Jackson Ultima splits its hollow guidance by discipline and skater size, not by one universal starting point.

Radius (figure)	Typical skater	Note
3/8 inch	Ice dancers	Shallow, favors long stable glides over bite
7/16 inch	Small or aggressive freestyle skaters	Extra bite for tight turns and jumps
1/2 to 5/8 inch	Most freestyle skaters	Jackson Ultima’s general freestyle range
About 1/2 inch	Tapered or parabolic blades	A different blade profile changes how the number feels

Notice that a figure dancer’s three eighths inch hollow is deeper than a hockey senior’s five eighths inch default. Deeper hollows are not just a setting for kids. Discipline and blade profile matter as much as body size.

How to choose a starting hollow

Skater weight is one of the biggest factors in hollow choice. Lighter skaters generally do better on a deeper hollow, and heavier skaters on a shallower one. More body weight already presses the edge into the ice, so a heavier skater needs less added bite.

Discipline factors in as well. Hockey, figure, and recreational skaters do not share one ideal starting point. That is why the two hollow tables above look so different from each other.

Ice hardness plays a role too. Skaters on hockey forums commonly report going shallower on soft or warm ice. A deep hollow can dig in and slow them down there.

Harder, colder ice tends to support a deeper hollow without feeling grabby. Ask your shop which end of the ladder fits the rink you skate on most.

Flat bottom V versus a traditional hollow

A newer option changes the shape of the cut entirely. Instead of one continuous curve, a flat bottom V grind cuts a flat channel across the blade. Two angled edges sit at the outer corners of that channel.

One popular version is sold under the name FIRE ring. The goal is to combine the bite of one hollow number with the glide of a shallower one. A half inch FIRE grind bites like a half inch but glides like an eleven sixteenths hollow.

Traditional round radius grinding is still what most players skate on. That is true at both the professional and amateur level. Flat bottom V is an option, not a replacement that has taken over the sport.

Some skaters do report changing habits after switching hollows. One regular on a hockey sharpening forum said he sharpens less often now. He had moved from a one inch traditional hollow to a three quarter inch flat bottom V grind.

Skate sharpening frequency: the honest range

Bauer’s guidance for competitive hockey players is specific. Sharpen every two to three hours of ice time. That is the number most shops quote as a general rule.

Real skaters report a much wider range on hockey forums. Some sharpen roughly every five hours of ice time. Others go one to two months between visits.

Figure skating guidance points to about thirty hours of ice as a starting benchmark. Real reported intervals on figure forums range from every two weeks to every five or six months. Weekly ice time in those reports was similar across skaters.

That spread is not random. Hollow depth, ice hardness, steel type, and skater weight all change how fast an edge actually dulls. Walking around off the ice on hard floors adds even more wear.

A shallow hollow leaves more steel supporting each edge. That edge stays useful longer than a deep hollow’s thinner edge. Switching to a shallower setting is a common fix when sharpenings start to feel too frequent.

What a fresh sharpening actually feels like

A freshly sharpened edge feels sharper than most skaters expect at first. Crossovers and stops often grip more than usual for a session or two. Some skaters describe the skate as grabbing the ice too eagerly at first.

Hockey players usually skate on a fresh edge right away. A light deburring pass is often the only prep needed. There is no standard break in period in hockey.

Figure skaters often feel differently about it. Many prefer a short break in period before a test or competition. New edges can make jumps feel easier while spins feel harder to control until the edge settles.

Either way, a day or two of normal skating is usually enough to settle into a new edge.

Cost: shop pricing versus home sharpening options

Shop pricing for skate sharpening varies by region and blade type. Treat any number here as a typical range, not a fixed price. A basic hockey sharpening commonly runs about five to fifteen dollars at a walk in shop.

Figure and precision work tends to cost more. Many skaters report paying around twenty dollars for a regular sharpening. Precision work on tapered or parabolic blades often runs thirty dollars or more.

Home machines exist for skaters who want to sharpen on their own schedule. A current Sparx home sharpener costs roughly nine hundred to just over thirteen hundred dollars, depending on the model. Each grinding ring for a different hollow or FIRE option costs about seventy five dollars more.

A cheaper tier also exists: small handheld hones. These are meant for touching up an edge between real sharpenings, not for replacing one. Owner reports describe them as useful for knocking down a light burr on the go.

That split mirrors the honing steel versus stone question in kitchen knives. A rod maintains an edge but cannot rebuild one that is already gone. Our comparison of honing steels and sharpening steels covers that difference in more detail.

A full home machine is not the only option worth weighing. A simple touch up hone might fit your situation better. Our sharpener matching tool can help you decide which one to buy.

Figure skating versus hockey sharpening

Figure and hockey sharpening diverge in a few practical ways beyond the hollow ladders. Figure blades carry a toe pick at the front. A shop grinding the hollow has to avoid running the wheel into it.

Tapered and parabolic figure blades change how a given radius number feels. The blade profile itself is not flat the way most hockey blades are. The same listed hollow can skate differently on a tapered blade than on a standard one.

Hockey players are more likely to be offered a flat bottom V option at a shop. It grew out of the hockey equipment market first. Both sports share the same underlying goal: removing a small, controlled amount of steel to create a fresh edge.

That is the same basic idea behind how any blade gets sharpened in the first place. Browse the rest of our sports and specialty sharpening guides for more on equipment across other blade types.

Frequently asked questions

How do I know when my skates need sharpening?

Watch for skates that slip sideways on crossovers or chatter through turns. A skate that will not hold an edge on stops is another sign. A quick fingernail test across the blade can reveal a dull edge before it becomes obvious on ice.

Do new skates need to be sharpened before first use?

Many skates ship with a rough factory edge, not a true finished hollow. A first sharpening dials in a proper radius of hollow for the skater’s weight and level. Ask the shop for a mid range hollow if you are not sure where to start.

Can you skate right after a sharpening?

For hockey, yes, most players go straight from the shop to the ice after a light deburring pass. Figure skaters often prefer a short break in period before an important test or competition.

What hollow should a beginner start with?

A shop default like five eighths inch works for most hockey skaters starting out. Figure skaters can start in the middle of their discipline’s range. Adjust deeper or shallower after a few sessions, based on feel.

Does a shallower hollow really make skates last longer between sharpenings?

Yes, in general. A shallower hollow leaves more steel supporting each edge. That edge takes longer to round off than a deep hollow’s thinner edge.

Does walking around off the ice dull skates faster?

Walking on concrete or bare rubber flooring is commonly blamed for faster dulling. Regular skaters describe this pattern often in forum discussions. A proper guard protects the edge between sessions and on the trip to the rink.

Is flat bottom V worth trying?

It is worth trying if you want to experiment with bite and glide. It is built around that exact tradeoff. Ask your shop whether flat bottom V is part of their regular skate sharpening menu before switching over.

Can a shop switch me from a traditional hollow to flat bottom V?

Yes, most shops that carry flat bottom V equipment can cut it on your existing blades. The blade steel does not need to be replaced for the switch. Ask about the closest flat bottom V option to your current hollow number before your next sharpening.

Curious what a shop visit should cost before you commit? Our guide to sharpening services and their prices covers skates alongside everything else.