inconsistent base bevel from montana

[Toddski13]

Doesn’t Montana use belts for sharpening the side edges?

@James primarily yes, they have a stand-alone disc machine called Race Edge and they offer the same technology as a module in some of their automated machines (though I’ve never seen one deployed that way). The belts help contribute to the lack of precision and consistency the data-based graphic I posted illustrates.

 

[Swiss Toni]

If the graphic of the disk grind you posted was based on data it would look like this

Probably better than what a Montana belt grinding unit can do, but not perfect, there is always some rounding and the surface isn't smooth.

To measure the edge angles and surface roughness Atomic uses an Alicona InfiniteFocus 3D surface measurement system https://www.alicona.com/products/infinitefocus/ this is what a magnified ground ski edge looks like

Montana is owned by a German company called Knoll Feinmechanik, all the machines are designed and built in Germany. Their main area of business seems to be the design and manufacture of automated systems for the pharmaceutical / medical device industry http://gb.knoll-feinmechanik.de/Company/3-10---.html

 

[Jacques]

I think I'll just stick to my "old fashion" hand tuning.

 

[tube77]

The issue here is not the variable base bevel the OP describes - rather it’s the methodology that is used to obtain this ‘radial’ tune and the consistency/reproducibility the machinery allows. There are a number of athletes and technicians who achieve a true variable base bevel (either by machine or by hand) but what they are doing is consistent and reproducible. Having just spent two weeks working with US Ski Team athletes at every level doing ski analysis, we saw a huge variance in base bevel, even with skis that were tuned at the same time, from machines that produce a radial tune. Some skis were nicely prepared with .7 in the tip and tail with a consistent .5 underfoot, but the vast majority were way over that and when using a true bar you quickly could see that the edges actually increased from .5 where the edge met the base to 1.5+ at the apex of the edge. Someone else mentioned belt edging and the inconsistencies that come with it... see the attached graphic that is a visual representation of measurements done to the micrometer and shows what a belt yields for side edge finish, especially when paired with a ‘radial’ tuning system that is imparting base bevel. I hear all the time how easy HTT base edge is for shops and that it’s “good enough” for our customers... I really wonder if these customers skied on a well prepared edge whether they’d agree that the rounded, inconsistent ‘radial’ tune was good enough. View attachment 86031

I presume there might be some skis that was prepared by hand with consistent base bevel from tip to tail unlike the machine prepared ones.
Did you have a chance to talk with the athletes if they prefer the consistent base bevel by hand over the varying bevel by machine?
I am curious what top level racers prefer for their racing day..
I am pretty sure they could immediately tell the difference between the two..

 

[tube77]

I think I'll just stick to my "old fashion" hand tuning.

That's what I prefer too...but I am quite scared to file the base by myself after totally screwing up two skis that eventually went into the machine in the end...

 

[Toddski13]

I presume there might be some skis that was prepared by hand with consistent base bevel from tip to tail unlike the machine prepared ones.
Did you have a chance to talk with the athletes if they prefer the consistent base bevel by hand over the varying bevel by machine?
I am curious what top level racers prefer for their racing day..
I am pretty sure they could immediately tell the difference between the two..

@tube77 you'd actually be surprised at the varying levels of feel among even the highest level athletes. Most can tell that they 'like' or 'dislike' a given base bevel, but feel between different angles eludes them. That said, my experience recently, and over the last twenty years is that consistent, non-variable base bevel (regardless of hand or machine finish) has been the consensus for a larger group of athletes at every level - especially with SL and GS skis. There are for sure some athletes who have preferred variable base bevel - Marcel Hirscher was one of them until the last season he competed - but typically they are using it with SG and DH.

Currently, except in instances of machine component failure, the standard for edges finished in the vast majority of ski factories and factory race rooms is consistent, non-variable base bevel.

 

[tube77]

@tube77 you'd actually be surprised at the varying levels of feel among even the highest level athletes. Most can tell that they 'like' or 'dislike' a given base bevel, but feel between different angles eludes them. That said, my experience recently, and over the last twenty years is that consistent, non-variable base bevel (regardless of hand or machine finish) has been the consensus for a larger group of athletes at every level - especially with SL and GS skis. There are for sure some athletes who have preferred variable base bevel - Marcel Hirscher was one of them until the last season he competed - but typically they are using it with SG and DH.

Currently, except in instances of machine component failure, the standard for edges finished in the vast majority of ski factories and factory race rooms is consistent, non-variable base bevel.

That's very nice to know! Appreciate it!

 

[ScottB]

tube77,

I am a race coach for a local ski team (youths) and we always recommend a constant base and edge tune. It is really what you want to be on. If you are into experimenting with variable bevel tunes and determine what you like, then that is fine as well.

I never new that Monatana machines produce variable base bevel tunes, and according to Toddski13, not very consistently. I can personally attest that a ski with a variable base bevel due to wear and age will not ski well, once corrected to a constant and propper (I like 0.5 base angle) bevel, the skis perform well again.

You need to find a shop with a Winterstieger machine. It might be worth trying your skis as is and see what you think.

 

[Swiss Toni]

It will probably be very difficult to get a constant bevel angle no matter which machine you use. I think all the edge grinding modules except the ones on the Svecom Delta Edge use ‘elastic’ grinding wheels. The abrasive is mixed with an elastomeric resin, usually polyurethane and cast in the size and shape required. The edges are sharpened with something akin to hard gummi stones rather than vitrified bond grinding wheels. Tyrolit the Austrian grinding wheel manufacturer that makes Wintersteiger’s 'ceramic disks' has recently introduced a number of 'elastic' files which they sell as an alternative to diamond files.

Unfortunately, their website is only in German https://www.tyrolitlife.com/sport-freizeit/ but they are available from Sidecut Tuning in Whistler https://www.sidecut.com/product/STO_TYRO_ELAS_2PC.html

The edge angle tolerance for most of the Wintersteiger automatic machines is ± 0.25° (some of the angles on the Mercury have a tolerance of ± 0.20°). I think the angles can only be set in pairs e.g. 1°/88°, 0.75°/87° etc. and it doesn’t look like it’s possible to set a 1°/87° (3°) combination. The edge angles can probably only be set individually on a Trimjet.

Rather than using a Montana machine to grind variable base edge angles on race skis it would be better to use a Wintersteiger Trim NC as it was designed for this. Unfortunately it doesn’t look like there is one in the US https://www.wintersteiger.com/en/Sk...kers/Ski-Service-Machines/References/Race-Lab

It would be interesting to know what the newer Reichmann machines are capable of. As well as ski tuning machines Reichmann also builds CNC grinding machines for grinding engine castings etc. so they should know a thing or two about grinding metal. Has anybody come across one?

 

[tube77]

tube77,

I am a race coach for a local ski team (youths) and we always recommend a constant base and edge tune. It is really what you want to be on. If you are into experimenting with variable bevel tunes and determine what you like, then that is fine as well.

I never new that Monatana machines produce variable base bevel tunes, and according to Toddski13, not very consistently. I can personally attest that a ski with a variable base bevel due to wear and age will not ski well, once corrected to a constant and propper (I like 0.5 base angle) bevel, the skis perform well again.

You need to find a shop with a Winterstieger machine. It might be worth trying your skis as is and see what you think.

Thank you for your comments!! Will try!

 

[oldschoolskier]

What I find funny in tuning discussions particularly those with machine and what they can’t do and can do, is that most don’t understand sharpening in terms if metal work.

Setting edge angles on a machine should get them to a near perfect edge. Particularly a flat base as a starting point. How you set the final angle is up to you.

The reason I say this is that machinists, tool and die makers, knife makers do this on a regular basis with anything from a simple grinder, belt sander up to complex machines on the tools and knifes that the make or need.

So seriously, if the final result is not good it is simply one of three things:

1. Poor operator.
2. Machine out of adjustment.
3. Both!

So stop overthinking this stuff its not rocket science .

 

[Jacques]

Stop overthinking this stuff its not rocket science .

It's not rocket science. It's good hands doing good hand work. Machines have no feelings!