Edges

From the Toko Snowboard Tech Manual found here:

EDGE TUNING
The base edge on a snowboard should have a bevel of a half to one degree. A little base bevel makes the board easy to ride and transitioning from toe edge to heel edge without being “grabby”. Base bevel of more than one degree makes the board feel “slippery” and turns have to be skidded because the edge is not close enough to the snow to hook up.

Side edge bevel on a board will depend on the conditions and the rider’s ability. One degree of side bevel is enough for softer conditions and forgiving to beginning to intermediate riders. Two degree side edge grips better on harder snow, this lets a stronger rider lay over in a harder turn. For racing or carving on hard icy slopes a side edge bevel of three degrees will hold, but will take some muscle to control.

From a recent Toko eBlast:

Vic Wild Checks in from Parallel Slalom WC in Yongpyong, Korea

Tough race today just wasn’t able to figure out the course.

The snow here is artificial, old and dirty. Ran HF blue on the edge of the base and HF grey over the rest. Most important for me are edges, I run a .5 degree base bevel and 2 on the side. On very aggressive and grippy snow I like to use fiber-tex to smooth and detune the edge this can be done on the slope its quick and you can adjust the detune and sharpness of the edge with just a few passes.

Vic Wild

As noted, it doesn’t take much to detune an edge and generally, you may be better off leaving your edges sharp. Before considering detuning, be sure to eliminate the possibility of a hanging burr if you are experiencing ‘hooky/grabby’ edges. With a smooth and sharp edge, you have better control over more variable snow conditions and terrain while rec riding than what you would find in a typically consistent race course. It takes little time to adjust side edge angles to try out either a 1° or 2° to find your preference. Reducing base edge angles requires base material removal and is far more difficult than side edge adjustments. Focus your tuning on the side edges. Detune as a last resort after spending time on a variety of conditions and trying to feather into carves.

Out of curiosity and a recent discussion with a customer prompted me to perform an unscientific experiment to provide a ‘meter’ for tweaking edge geometry. I think many are over thinking how much is really involved with removing 1° of edge material. It is in fact, fast and easy because little material removal is involved. Hopefully, this will help people to get less concerned about obsessing over angles and experiment on your own.

The conventional wisdom for setting or adjusting edge geometry is to use a progression of files, before changing to stones or diamonds for final polishing and honing. Depending on coarseness, files take off more material, much faster than stones or diamonds. This can be advantageous on one hand while a problem for some on the other hand for the same reasons.

Diamonds are far more forgiving and less intimidating than a typical bastard file and a 100 grit diamond is considered a ‘cutting’ tool, much like a super fine file.

So….under super clean, ‘highly technical’ conditions, I went from a 3° to a 2° and back on all four edges using an Ice Cut bastard file, 2nd file and 100 grit SVST on different edges. After removing the side walls and marking the edges with a Sharpie and following all options with a 200x, 400x and 600x diamond, I generally found:

-Bastard file- one overlapping pass got me close, a second more than changed the angle. One overlapping pass, followed by a few passes with a 100x should be adequate.

-2nd Cut file-3 overlapping passes followed by a few overlapping passes with the 100x and the other diamonds.

-100x diamond-5 fast, overlapping up and downs (10 passes).

By the time you clean files and swap cutting tools, the options were in relatively the same neighborhood of a couple minutes. If the edges were more chewed up, the files would have been much faster. To assure minimal material material removal, use the 100x diamond. To make more than sure, use a bastard at least twice, possibly followed by a pass or two with a second and then diamonds.

Following is a rough video using a bastard file on one edge to adjust edge geometry and then a diamond to Change Edge Angles on the second edge:

(You may need to refresh your screen to view. Firefox seems to have trouble loading this video.)

The following ‘in process’ school video project may provide you and others with visual aids and another perspective on diamonds, files and edge tuning. The edge tools used in this video can be found here.

For those parents whose teenager knows more than you do for all things technical, here is:

Sharp and smoothly polished edges, with correct edge geometry (aka properly ‘tuned’) are critical to maximize the carving capability and overall performance of your expensive board(s). What tools and techniques do you employ?

There are simply too many variables to grasp without time, experience, defining personal goals, cost and other considerations. As with skis, snowboards and other gear, you can always buy more and there are various grades or calibers of tools. For the recreational skier and tuner, getting every one of the finest tools may be overkill and an unnecessary expense. But if you appreciate fine tools, and start out purchasing them, it’s hard to go back to lessor caliber as you become spoiled.

For the recreational enthusiast, a 1 degree base and 3 degree side is probably the most common edge angle for most skis and boards and works particularly well on ice and hard man-made snow (conditions the majority are faced with, particularly out East). That’s of course assuming the edges are sharp and polished.

A 2 degree side bevel could be considered for softer snow – typical conditions most of the time in the Rockies. Many feel that there is not a downside to using a 1/3 (base/side) bevel angle for recreational skiers and that it is not acute enough of an angle to reduce sharpness quickly on abrasive snows and ice.

Many performance minded skiers on hard snows may prefer a .5 or .7 degree base bevel. It is easier to increase the base bevel versus reducing if you are experimenting since you will need to remove base material to reduce the base bevel angle.

A straight forward, low tech method for measuring base bevels is to use feeler gauges or other objects of known thicknesses (0.5mm, 0.7mm, 1.0mm, etc).

The direct ratio between typical bevel angles, is the metric height (mm) of the angle, at the accepted distance and easy to remember distance of 60 mm/6cm from the edge (actually 57.3mm).

The SVST WC Tru Bar has an engraved line at this location to facilitate easy and quick base bevel measurements. Any true bar can be marked at this location and used to measure the base bevel angle by measuring the height above the base when the bar is parallel to the edge.

If a feeler gauge isn’t handy, a typical credit card measures 0.8mm and 1.25mm at the raised lettering.

How flat (or not) are my bases? What are my base bevel angles? How straight are my scrapers, edge guides & tools?….are among the typical bits of information needed to perform and gauge quality of work and determine what work is required.
Like any tool we carry, there is a range of quality levels available to meet budget, personal goals and acceptable tolerances. From basic straight metal bars to precise, finely milled, high quality case hardened steel, the DIY tuner can achieve the desired and necessary level of precision using the fundamental tool known as a true bar.

For base work, a good backlighting source like a desk lamp, daylight, flashlight, etc is very important to help you see any variations between the bar and base. By clearly identifying irregularities and locations the guesswork is minimized.
The basic types are rectangular, square or round section bar stock of varying levels of precision and finishes for the recreational tuner, or a highly milled ‘knife edged’ precision true barfor those with tighter tolerances for their boards. A ‘hybrid’ of sorts, is a finely milled base skiver which can also be used for base repair and flattening tasks.

The narrower the section, the less ‘forgiving’ the lighting will be and increase accuracy. A wider square or rectangular bar will allow less light to pass between it and the base versus a round bar and far less than a knife edged bar.By turning a square or rectangular bar stock true bar on edge, you can increase the accuracy, as long as the quality of the bar stock is acceptable.

Typical base issues are flat, high, low (below) or both (as seen above). A perfectly flat base is ideal while some irregularity may be acceptable for some, depending on performance level or typical snow type. A backcountry or powder ski or snowboard has less of a need for perfection than a high performance race ski or snowboard.

Regardless, knowing ‘where they are’ is important.

Additionally, many new skis and snowboards are anything but flat.

A low base (concave) will cause

the edges to ‘rail’ or grab more readily than desired and harder to release, while high

bases (convex) will require more

angulation and time to get to an edge.

Achieving a flat base is also imperative if you also wish to achieve high precision while tuning edges since all bevel angles and tools are relative to an assumed flat base.