Tonttuwerks Stone Grinding


"At the end of the day, a stone grind machine is just that. A machine. A tool. Knowing what do with it – when, why, and how to employ its use – that's what matters."

"Grinding a pair of skis is more than simply guiding them over a rotating stone. It's both science and art. A science and art at the center of the mission of Tonttuwerks/Finn Sisu."

Touring Refresher Grind
Touring Refresher Grind
Touring Refresher Grind

Over time, a touring ski base picks up a mixture of scratches and uneven, concave, or convex ski surfaces. The intent of this grind is to reasonably clean up this condition and make it easier to glide wax and look at.**

Standard Refresher Grind
Standard Refresher Grind
Standard Refresher Grind

Similar to a standard stone grind, but with fewer passes over stone. Best suited to quickly remove minor base damage to get skis up to speed for important races.**

Only available for well cared-for skis previously ground by Finn Sisu within the last 2 years to ensure flatness.

Stone grind

A three-step process that begins with flattening and removing damaged base material caused by frequent cold wax ironing and consistent skiing on cold abrasive Midwestern snows. Ski bases are then ground smooth before a final structure (a pattern of etched lines) is applied that has been researched and glide tested to confirm exceptional glide characteristics.**

Stonegrind w/ Prep
Stone grind w/ Prep
Stone grind w/ Hardening Prep

Includes a standard stone grind and an additional finish with glide wax hardening, a necessity for Upper Midwestern natural and man-made snows. Includes non-fluorinated base prep and base hardening, both in our hot-box, in addition to standard handwork, brushing, and treatment of Rex glide cleaner.


*A $10.00 cleaning surcharge will be applied to each pair of skis not thoroughly pre-cleaned of kick and/or glide wax.

**Includes handwork, brushing, treatment of Rex glide cleaner, and the first layer of an iron-on base prep.

Skate Grind Menu


Approximately 10°F and colder — Cold dry abrasive manmade or natural, hard or soft snow.


Approximately 10°F to 25°F — Uni range. Cold dry abrasive manmade or natural, hard or soft snow.


Approximately 25°F to 32°F — Some humidity present in snow.


Approximately 30°F to 35°F — Moister snow, about when you can start making a snowball.


Classic Grind Menu


Approximately 10°F and colder — Manmade or natural snow.


Approximately 10°F to 30°F — Uni range. Manmade or natural snow.


Approximately 25°F to 32°F — Some humidity present in snow.


Approximately 30°F to 35°F — Tracks becoming wet but not saturated.


*Hand structuring available upon customer request over any of the above grinds. Ask about additional off-menu grinds for narrower ranges and conditions outside the Midwest. Call/email Tom Novak ([email protected]) or come in for recommendations.

**Note—Excessively uneven bases are sometimes impossible to fully grind flat. This can be due to simple wear or some manufacturers design and choice of core materials that have a high susceptibility to thermal damage (i.e. when iron-waxing skis). Tom strives to get skis flat, but it is not always possible—your ski base has only so much polyethylene.

tom on grinder


Super Sander…

Belt grinders…

Metal Scraping…

Stone grinders…

The evolution of Nordic ski base maintenance.


Wintersteiger Micro 1

In 1993, Finn Sisu purchased the first stone grinding machine dedicated to Nordic ski maintenance in the Upper Midwest—the Austrian built Wintersteiger Micro 1. A state of the art tool to refinish Nordic ski bases, the Micro 1 allowed Nordic skiers to benefit from the same technology that alpine skiers had been benefiting from for years. No longer needing to spend hours in the basement meticulously sanding and/or metal scraping their ski bases, skiers flocked to the original store location on University Ave in Saint Paul, MN to have their ski bases mechanically ground, flattened and structured. Over time, other Upper Midwest ski retailers invested in their own stone grinding machines, contributing to a wealth of grinds that skiers could choose from to make their skis faster.


Wintersteiger Omega RS 150

As ski structures evolved, so too did the capabilities of stone grinding machines. Fast forward to 2015 and Finn Sisu decided to raise the bar for Nordic ski maintenance once again with its purchase of the Wintersteiger Omega RS 150—a semi-automated stone grinding machine with software that rivaled that of some of the most advanced machines out there. One of only five in the United States at the time, the Omega RS 150 was built-to-order, with each subsequent machine produced being an upgrade over the previous. With the more aggressive pink stone on the Micro 1, and a finer grey-brown stone on the new Omega RS 150, the two machines perfectly complemented each other—the Micro 1 flattening and thoroughly removing damaged base material, and the Omega RS 150 polishing and carefully structuring the blanked base.


Wintersteiger Race NC

Around rolls 2020 and, in the midst of other prominent events, Paul Suomi from Vail’s Ski and Snowboard Academy offers Finn Sisu the opportunity to acquire a Wintersteiger Race NC, the finest, fully programmable stone grinding machine Wintersteiger offers. With a total of about a dozen of these machines in existence, and only 3 of those machines residing in the United States, Finn Sisu (with an incredible amount of help from Paul) jumped at the chance to move 1 of those 3 machines to the new store location in Lauderdale, MN. Used almost exclusively by ski manufactures like Salomon, Atomic, and Fischer, and national ski teams like Austria, Germany, Sweden, and Norway, these two-axis CNC (computer numerical control) manual machines produce the most accurate and precise reproducible structures grind techs can dream up. Working in tandem with the Omega RS 150, the Race NC and Omega RS 150 make, arguably, the most capable duo of stone grinding machines anywhere in the United States with the potential to deliver some of the best grinds available to skiers in the Nordic racing community.


Wintersteiger Relationship

Left to right: Paul Suomi, Ahvo Taipale, Tom Novak.

At the end of the day, the relationship between Finn Sisu and Wintersteiger spans nearly three decades in addition to three stone grinding machines. Located in Salt Lake City, UT where they warehouse parts and supplies, Wintersteiger USA’s excellent customer service has been paramount to the closeness of this relationship, with Wintersteiger USA offering real-time tech support alongside their team of regional tech representatives who provide onsite consultations and servicing for their machines.


Wintersteiger Relationship

Brent Johnson, Midwest area Wintersteiger tech rep and our Wintersteiger whisperer, and Tom Novak, our stone grinding master goblin.

If you have any questions, theories, or just want to talk about structure, feel free to contact Tom Novak at Finn Sisu: 651-645-2443 or [email protected].