Skate sharpening — what the hollow does and how to choose one
The number the shop asks you for, what it actually changes underfoot, and how weight, ice temperature and skill should move it. Inches and millimetres, both ways.
Somebody behind a counter asks "what hollow?" and most new players say "whatever's normal". Here is what they are actually asking, and why the answer is worth thinking about once.
Your blade is not flat
A hockey blade is not a flat strip of steel. A grinding wheel cuts a concave arc into the bottom of it, leaving two edges — inside and outside — with a hollow between them. That arc is described by the radius of the wheel that cut it: the radius of hollow, or ROH.
Here is the counter-intuitive part: a smaller number is a deeper hollow. A 1/2" hollow is deeper and bites harder than a 1" hollow.
| Hollow | Metric | Feel |
|---|---|---|
| 1/2" | 13 mm | Deep — most bite, least glide |
| 5/8" | 16 mm | Deep-ish; with 1/2" one of the two common shop defaults |
| 3/4" | 19 mm | Middle ground |
| 7/8" | 22 mm | Shallower; noticeably more glide |
| 1" | 25 mm | Shallow — fast, but you must trust your edges |
| 1 1/4" | 31 mm | Very shallow; specialist |
Unless you ask for something specific, most shops will sharpen at 1/2" (13 mm) or 5/8" (16 mm).
What changes when you change it
- Deeper (smaller number): more grip. Harder stops, tighter turns, more confident starts. It also digs into the ice more, so you glide less and your legs work harder over a full game.
- Shallower (larger number): more glide and more speed for the same effort, and less fatigue. But less bite, so stops and hard turns need better technique.
Three things should push your choice:
- Your weight. A lighter skater presses less steel into the ice and generally wants a deeper hollow to get enough bite. A heavier or stronger skater is already penetrating the ice plenty, and usually benefits from something shallower.
- Ice temperature. Cold, hard ice is harder to dig into, which favours a deeper cut. Warm, soft ice lets the blade sink in on its own, which favours a shallower one to stop the blade dragging.
- What you are complaining about. Sliding out of stops and turns? Go deeper. Legs burning by the second period and feeling slow in a straight line? Go shallower.
Change one step at a time and skate on it for a few sessions before deciding. Most players eventually settle a step or two shallower than the shop default.
Flat Bottom V, briefly
Some shops offer Flat Bottom V (FBV), which replaces the curved hollow with a flat channel between two sharper edges. It is described by two numbers rather than one — 100/50 and 90/1 are the common cuts, roughly comparable in feel to a 1/2" and a 5/8" traditional hollow. Players who try it often report grip and glide at the same time. It needs a shop with the right equipment, and it is not better or worse, just different.
Profiling is a different thing
Sharpening shapes the blade across its width. Profiling (or rocker) shapes it along its length — how much of the blade touches the ice at once. A flatter profile gives stability and straight-line speed; a rounder one gives agility and quicker turns. It is a less frequent, more expensive service, and it is worth asking about only once your skating is settled.
How often?
The honest answer is "when they feel wrong", and the ranges published are wide: as often as every two to three hours of ice time for a competitive player, and commonly cited rules of thumb of 15 to 30 hours for recreational skaters. Your weight, your stride and the ice you skate on all move it.
Quick field test: run a thumbnail lightly across the edge (across it, never along it). A sharp edge shaves a sliver of nail. If it slides over, book a sharpen. Nicks and rust also mean it is time.
Looking after the steel
- Hard guards to walk in — never store skates in them, because trapped moisture rusts the steel.
- Soft soakers for the bag, after you have dried the blades with a towel.
- Wipe the blades after every skate. Rust is what actually kills steel, not skating.
Sources. Bauer's published sharpening guidance for hollow ranges, defaults and the weight/ice-temperature effects, with a sharpening-equipment maker's guidance corroborating the weight relationship; Blackstone's Flat Bottom V for the FBV description. Millimetre equivalents are as published by the source. Checked September 2026.