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Edge grinding vs. hand tuning

post #1 of 19
Thread Starter 
Cap'nK I want to respond but I don't want to hyjack the base-grinder design thread. I'm starting a new thread... my response is at the bottom...
Quote:
Originally Posted by CaptainKirk View Post


Panzer file to a thin edge race ski? LOL. You would be lucky if you had any edge left after the third week of training.

You can diamond stone all you want, it will never get the edge as sharp as a grinder like the SnowGlide. There is a reason why nobody hand files on the World Cup anymore.
Quote:
BTW, I'm not a race parent, just a Level 300 coach who often has to fix botched hand tuning jobs done by well meaning parents. They would be better off having an affordable edge grinder that actually works instead of trying to hand tune 6 pairs of their kid's race skis at 2 am the night before a state qualifier race...

In WC circuit the cost of a $2000 machine obviously isn't an issue. Everybody is going to follow what everybody else is doing to keep the playing field "equal", regardless of cost, until a maverick comes along willing to try something different that turns out to give them an advantage. Then everybody else jumps on that bandwagon.

But
Quote:
Originally Posted by CaptainKirk View Post

Quote:
Quote:
Originally Posted by gdeangel View Post

I guess there are a lot of kids out there who are good enough to get real race stock skis with those thin edges, not just off-the-shelf racing skis. If they are that good, are mom and dad really going to that clueless about overusing the panzer / skiver?


And by the way, as good as the Snow Glide is, run out from a mechanical grind still requires finishing with a stone.

First, yes, there are a bunch of really good kids around here who are on real race skis. Even "off the shelf" race skis purchased from factory reps have a much thinner edge than any all mountain ski.


Nobody takes a panzer file to a race ski other than to set the initial side edge bevel. A coarse file takes off way too much edge on a ski that has little edge width to begin with.

If you are calling the hanging burr "run out", then you are right, it needs removed along the base edge either by a fine stone or hard gummy. The hanging burr is there regardless if you hand tune or use a grinder.

What you do not want to do is remove the fine cross hatch pattern on the side edge left by the grinder by polishing it out. Polishing parallel to the edge defeats the whole purpose of sharpening perpendicular to the edge (think how you sharpen a wood chisel) For speed skis, you still use the grinder, but switch to a finer grit wheel.

The problem with most race families is the sheer volume of hand tuning multiple skis for multiple kids multiple times per week. Most younger racers do not have the skill at their age to use hand tools effectively, so it ends up on the parents plate to do. That can be a grind (no pun intended) to a stressed out race parent during the season, who also has to drive the kids to races, volunteer at races, and be a ski tech at the same time.

The top grinders on the market really work, and produce an edge superior to any hand method. The issue is they are crazy expensive. My point was if someone designed something that was easy to handle like the SnowGlide or ProTek, and sold for a more reasonable price, there would be a market for it. It could be a simpler machine, use more off the shelf parts, but still be high quality, and would not have to be designed to hold up to constant back shop use.

Usually I'd expect to be able to skive or panzer file maybe two - three times tops over the life of a ski which are going to have at least 3 seasons of life in them for an "average" Jr. racer who saves one edge for racing and skis the other one for training and misc. frontside fun. I know that's not how "elites" ski, and their equipment is spec'd differently. I have to suspect that your talking about thin edges on off-the-rack race skis that are Jr lines designed to be particularly light. Just a guess. Those are skis that will be outgrown before they are skiied out, so a thinner edge would be great at killing the market for secondary sales among junior racers - which incidentally how I got a good deal of stuff when I was starting to race years ago and how I learned about tuning skis. You imply that if you skive once, then after you've tuned the edge back to the sidewall, you have to throw out the ski. I guess I lucked out because I'm looking at the brand new "multi-event, non-FIS" Jr. race ski that I just bought last week for my 11 y.o. and the edges from the factory look just as thick as other edges I'm used to working on. Perhaps also in doing initial bevels by hand sparingly with a combination of panzer file or trying to very carefully to free-hand skive with the SkiVisions block and finish with a cross-cut file that can cute sidewall relatively good without clogging up every pass... that such an approach leaves more of the original edge than an initial setup done by machine. I don't know because I've yet to personally see the thin edge skis on the kind of off-the-rack skis your citing. What % of the junior racers do you see on that kind of ski?

Now, I am also really and genuinely curious about the benefits of leaving the cross hatch from the grinding. On a new ski I was always taught to polish that off. The reason I thought you GRIND perpendicular to the edge (including when sharpening a chisel) is because of the grinding surface geometry and the equilibrium of forces as you grind. Plus it leaves any run out (burr) where you can easily remove it when you do the final polishing / honing. If I was HAND sharpening a chisel I would use a circular motion against the honing block that would produce the kind of swirl marks your talking about on the ski edge, but I always thought that had more to do with polishing evenly vs. the tendency to overbear one side if you slide the tool surface strictly perpendicular to the stone. When filing or polishing a ski edge by hand, the guide takes care of that unless, in the kind of situation you're seeing, someone's arm slips at 2AM.

In other contexts, If I was polishing an drive shaft I would polish it parallel to the direction of rotation. For a bearing, I might polish it using a process that leaves a swirl pattern but that is to prevent unevenness that could wear on the moving parts unevenly. I don't think that's a consideration for polishing a ski edge.

Anyway, back to tuning... I'm sure somebody in the WC circles went out there and put an electron microscope on traditionally polished edges and swirled edges. So is there actually evidence that the swirled edges run faster due to their geometric texture or something like that, or are they somehow just smoother than you can get with a fine diamond / ceramic?
post #2 of 19
Quote:
Originally Posted by gdeangel View Post

Cap'nK I want to respond but I don't want to hyjack the base-grinder design thread. I'm starting a new thread... my response is at the bottom...
Usually I'd expect to be able to skive or panzer file maybe two - three times tops over the life of a ski which are going to have at least 3 seasons of life in them for an "average" Jr. racer who saves one edge for racing and skis the other one for training and misc. frontside fun. I know that's not how "elites" ski, and their equipment is spec'd differently. I have to suspect that your talking about thin edges on off-the-rack race skis that are Jr lines designed to be particularly light. Just a guess. Those are skis that will be outgrown before they are skiied out, so a thinner edge would be great at killing the market for secondary sales among junior racers - which incidentally how I got a good deal of stuff when I was starting to race years ago and how I learned about tuning skis. You imply that if you skive once, then after you've tuned the edge back to the sidewall, you have to throw out the ski. I guess I lucked out because I'm looking at the brand new "multi-event, non-FIS" Jr. race ski that I just bought last week for my 11 y.o. and the edges from the factory look just as thick as other edges I'm used to working on. Perhaps also in doing initial bevels by hand sparingly with a combination of panzer file or trying to very carefully to free-hand skive with the SkiVisions block and finish with a cross-cut file that can cute sidewall relatively good without clogging up every pass... that such an approach leaves more of the original edge than an initial setup done by machine. I don't know because I've yet to personally see the thin edge skis on the kind of off-the-rack skis your citing. What % of the junior racers do you see on that kind of ski?

Now, I am also really and genuinely curious about the benefits of leaving the cross hatch from the grinding. On a new ski I was always taught to polish that off. The reason I thought you GRIND perpendicular to the edge (including when sharpening a chisel) is because of the grinding surface geometry and the equilibrium of forces as you grind. Plus it leaves any run out (burr) where you can easily remove it when you do the final polishing / honing. If I was HAND sharpening a chisel I would use a circular motion against the honing block that would produce the kind of swirl marks your talking about on the ski edge, but I always thought that had more to do with polishing evenly vs. the tendency to overbear one side if you slide the tool surface strictly perpendicular to the stone. When filing or polishing a ski edge by hand, the guide takes care of that unless, in the kind of situation you're seeing, someone's arm slips at 2AM.

In other contexts, If I was polishing an drive shaft I would polish it parallel to the direction of rotation. For a bearing, I might polish it using a process that leaves a swirl pattern but that is to prevent unevenness that could wear on the moving parts unevenly. I don't think that's a consideration for polishing a ski edge.

Anyway, back to tuning... I'm sure somebody in the WC circles went out there and put an electron microscope on traditionally polished edges and swirled edges. So is there actually evidence that the swirled edges run faster due to their geometric texture or something like that, or are they somehow just smoother than you can get with a fine diamond / ceramic?

Swirled edges as you call them is a Ceramic Disc finish and is by far the best grippiest edge finish out there. I leave it on any new skis I get as long as I can. 

 

And you must remove the hanging burr regardless of how the skis were sharpened. 

post #3 of 19

Junior Multi event skis do have thicker edges. When you get up to the "tweener" skis that have adult construction, but flex for lighter weight skiers, you will see the same thin edges as the FIS skis. Most of our good U14s are on the tweener SL and GS skis. Most of our better U16 and U19 are going to full FIS skis. Base plastic glides faster than steel edge, so true race skis minimize the width of the edge.

 

I am not an expert on ski edge metallurgy, so I can only say what I have told by factory reps, current and ex-WC tuners, and found on my own skis: you can't get the same edge from hand tuning as from a top of the line grinder. Other users of this forum who have access to these grinders have stated the same thing. The best grinders remove far less material, and make the ski grab better on ice. On my own skis I have resharpened the grind by hand when dull, and the ski does not have the same grip on ice. I know all the tricks of hand tuning, have been doing it for 40 years, and do it well. Borrow a grinder, and the edge hold on ice is back.

 

I have no idea if this is true: One WC guy told me that when sharping by hand, along the edge, there are small bits of the stone that overhang the base edge, putting a small, almost microscopic rounding on the edge along the entire length. The grinders swipe across the edge, so this is eliminated, and the result is better grab on rock hard ice.

 

I don't know if that is what really happens, but I do know there is a noticeable difference on how the edge grips on ice, and if you follow up with a hand tune, even with the best of equipment and stones, it just isn't the same. On top of that, you always end up removing more edge no matter how skilled you are.

post #4 of 19

When it comes to tuning, here are the few you really should read and listen to.  Atomicman, ScotsSkier and Chenzo are the short list.

post #5 of 19

Nothing much to argue with here. You can get a very sharp edge using files and stones, but a machine will get you there in three or four passes per edge. Stones take a lot more time. If you are tuning one pair of skis that isn't too important. If you have several pair to tune, that adds up to a lot of time. It is the same argument with rotobrush vs. hand brush. You can do a perfectly adequate job with an oval brush, but roto will get it done much faster. 

 

Quote:
 

Originally Posted by CaptainKirk View Post

BTW, I'm not a race parent, just a Level 300 coach who often has to fix botched hand tuning jobs done by well meaning parents. They would be better off having an affordable edge grinder that actually works instead of trying to hand tune 6 pairs of their kid's race skis at 2 am the night before a state qualifier race... 

 

 

Wow, you're nice. That's a ton of thankless work.

 

PS. I like my panzer. It's a tool and must be used carefully.


Edited by bigreen505 - 1/29/16 at 12:05pm
post #6 of 19
Quote:
Originally Posted by bigreen505 View Post
 

Nothing much to argue with here. You can get a very sharp edge using files and stones, but a machine will get you there in three or four passes per edge. Stones take a lot more time. If you are tuning one pair of skis that isn't too important. If you have several pair to tune, that adds up to a lot of time. It is the same argument with rotobrush vs. hand brush. You can do a perfectly adequate job with an oval brush, but roto will get it done much faster. 

 

PS. I like my panzer. Try changing edge angeles without one. 


Panzers have a use, and that is the main one.

 

Even better than a panzer for setting up initial edge angles is the coarse tungsten carbide file SVST sells. It ain't cheap, but man can it cut through steel quick.

post #7 of 19
Quote:
Originally Posted by CaptainKirk View Post
 


Panzers have a use, and that is the main one.

 

Even better than a panzer for setting up initial edge angles is the coarse tungsten carbide file SVST sells. It ain't cheap, but man can it cut through steel quick.

 

Yeah, I've been eyeing those. Swix has some too. I just don't need them often enough to justify it, but tempting. 

post #8 of 19

Buy the carbide files. You only live once! They sell a set of 3, coarse, medium and fine at a discount (if you can call it that)

 

I use the fine the most if the edge is really dull from hitting dirty ice. No pressure needed, and it gets the edge back in one or two passes.

 

Carbide is really hard material, so they outlast many, many steel files. Probably saves money in the long run.

 

One thing: Don't drop them on a concrete floor, they will shatter like ceramic.

 

Don't ever see me going back to steel files after using the carbides...a least until I get a good grinder for myself. :D 

post #9 of 19
Quote:

Originally Posted by bigreen505 View Post

 

Wow, you're nice. That's a ton of thankless work.

 

When I look at the extra (unpaid) time I have put into coaching, I have probably lost money on every gig I have ever had. But it is worth it just to see the smiles on the kids faces when everything is working for them.

post #10 of 19
Quote:
Originally Posted by CaptainKirk View Post
 

Carbide is really hard material, so they outlast many, many steel files. Probably saves money in the long run.

 

One thing: Don't drop them on a concrete floor, they will shatter like ceramic.

 

One might think it's an exaggeration when you hear about the tungsten carbide files breaking if they are dropped but I can, unfortunately, confirm this is no exaggeration.  I won't say they'll bust every time you drop them but if the are dropped on a bare concrete floor and happen to land relatively flat, my suggestion is to NOT look down, leave the room immediately, if you drink, go have a beer or mix yourself a cocktail and wait at least 30 minutes before returning to the scene of the crime.  It'll save you from anyone seeing a grown man cry and or, anyone hearing you scream a whole lot of unpleasant words and phrases.

 

Also, and this works for other edge tuning tools such as ceramics or any of the hard stones, but consider leaving that build up of wax drippings on the floor till at least the end of the season.  It helps create somewhat of a cushion and can potentially save you from any of those angry outbursts.:D

post #11 of 19
Thread Starter 
Quote:
Originally Posted by CaptainKirk View Post


I have no idea if this is true: One WC guy told me that when sharping by hand, along the edge, there are small bits of the stone that overhang the base edge, putting a small, almost microscopic rounding on the edge along the entire length. The grinders swipe across the edge, so this is eliminated, and the result is better grab on rock hard ice.

That's interesting. It makes a lot of sense particularly with a manufactured diamond stone, and it's the reason it's important to periodically re-dress the ceramic stones that will develop grooves otherwise. The face grinding wheels would not suffer that kind of problem due to the way they are cutting but a cylinder cutting at it's circumference would.

Typically when I am setting bevels and final edge polish I use the ski visions edge tool for. One reason it that is it's actually kinda akward to grip, so you don't get much leverage like using a file + guide forcing many light passes. And their panzer has just a few teeth so probably safer wrt changing the side bevels - still have use care. The polishing stones need redressing to avoid exactly what you described.

There is something else though and that is how quickly the edge breaks down. Running with the analogy to sharpening a chisel, I notice that a machine ground hand tool tends to hold it's edge better than the hand sharpened one, even though, and we might have to agree to disagree here, I find that immediately after sharpening, the tool cuts with less effort when I had hand sharpened it (i.e., seems sharper).

If you read up on what the Ski Visions guy has to say in his literature about edges, he extols the tool for removing "factory hardened" edges, which, in their view, makes future tuning easier. That also supports the idea that the ceramic disc finishing process creates a more durable edge than can last through several runs on a race course, while in the ski visions / hand tuning approach might only produces an equivalently sharp edge that can < 1 run in those kind of abrasive conditions (vs. the typical soft stuff that the recreational "performance" customer buying their produce would encounter).
post #12 of 19

@CaptainKirk,

 

You're right on the money with the need for an edge grinder at a certain point for racers, even juniors.  Quality of edge, durability of edge, life of the skis (especially slalom skis), and most importantly time saved.  I've got a U16 and a FIS racer, and we usually do 2-6 pairs a night, 6 nights a week in our garage.  Up til this year we had done the skis by hand, and I think had done them pretty well, but getting an edge machine this year has been eye opening.The skis are consistently bladed, edging the skis takes way less time than waxing now, and the kids are getting more homework done.  Anyone have a power scraper?  After the better part of a season on injected snow the skis still have the majority of their edge left - this wasn't the case with hand tuning! 

 

About the need for a reasonable machine.  We're beta testing an affordable edge grinder from a local engineer/machinist/race parent/coach which may meet your needs.  Think snowglide-ish form factor but battery powered so no dangling wires, at a much lower price point.  I've compared it with snowglide, wintersteiger and trione, and the finish compares well. PM me with your contact info and I'll pass it along to the developer for when he's ready to go public. 

post #13 of 19

It could be that the heat from the mechanical grinder case hardens the thinnest part of the edge a bit.

post #14 of 19

Just to correct one info... "There is a reason why nobody hand files on the World Cup anymore." is not really correct ;) Pretty much noone on speed part of WC tour is using machines, but they file by hand, and I would say more then 50% of top racers in tech events have skis prepared by hand (most of service guys have machines there if sometimes they are needed, so it's not that they use files because they wouldn't have machines). ;) But I agree, that there's simply no way to have edge as sharp by hand, as it can be done with machine.

post #15 of 19

In my experience with ski tuning in general, the man vs. machine issue in dependent on the "man' (or woman) who is doing the work. Many of us are told that the machines are so automated that they are fool proof, but in my experience that is not the case. Those machines need to be regularly calibrated and there are settings that can be screwed up with an inexperienced and/or uncaring operator, which unfortunately is the case more often than not. That being said, I believe that in the hands of an expert and caring operator, and all things being equal, we can bet a better and more accurate edge sets with a high quality, well calibrated machine. Get to know the actual person who is going to tune your skis, not just the guy that's going to write up the ticket for you, and make sure they will be willing to verify the accuracy of the work when the job is done. I'd much prefer my skis be hand tuned by a WC tuner, (the likes of  Willi Wiltz), than the average midnight rambler that I have never met, working the night shift in a ski shop. (Of course Willi uses machines in his shop too.) Most of us don't have access to a WC tuner though!.   So..... let the buyer beware!

post #16 of 19

Skismoke when we were talking about machines here it wasn't about machines ski services have in their shop, but about handheld machines like Trione and similar.

post #17 of 19
Quote:
Originally Posted by MoJo23 View Post
 

One might think it's an exaggeration when you hear about the tungsten carbide files breaking if they are dropped but I can, unfortunately, confirm this is no exaggeration.  I won't say they'll bust every time you drop them but if the are dropped on a bare concrete floor and happen to land relatively flat, my suggestion is to NOT look down, leave the room immediately, if you drink, go have a beer or mix yourself a cocktail and wait at least 30 minutes before returning to the scene of the crime.  It'll save you from anyone seeing a grown man cry and or, anyone hearing you scream a whole lot of unpleasant words and phrases.

 

Also, and this works for other edge tuning tools such as ceramics or any of the hard stones, but consider leaving that build up of wax drippings on the floor till at least the end of the season.  It helps create somewhat of a cushion and can potentially save you from any of those angry outbursts.:D

 

Linoleum

 

I use it next to my milling machine so if I drop a tool part of precision part it doesn't break or get dinged.

Now and then I take it outside and scrub it off to clean and throw it back on the concrete floor next to the mill.

post #18 of 19
Quote:
Originally Posted by Skismoke View Post
 

In my experience with ski tuning in general, the man vs. machine issue in dependent on the "man' (or woman) who is doing the work. Many of us are told that the machines are so automated that they are fool proof, but in my experience that is not the case. Those machines need to be regularly calibrated and there are settings that can be screwed up with an inexperienced and/or uncaring operator, which unfortunately is the case more often than not. That being said, I believe that in the hands of an expert and caring operator, and all things being equal, we can bet a better and more accurate edge sets with a high quality, well calibrated machine. Get to know the actual person who is going to tune your skis, not just the guy that's going to write up the ticket for you, and make sure they will be willing to verify the accuracy of the work when the job is done. I'd much prefer my skis be hand tuned by a WC tuner, (the likes of  Willi Wiltz), than the average midnight rambler that I have never met, working the night shift in a ski shop. (Of course Willi uses machines in his shop too.) Most of us don't have access to a WC tuner though!.   So..... let the buyer beware!

Like CNC machinists they get lazy and the machine get out of spec and then the spit out a 100 parts all not quite right.

It seems less and less of them theses day take care to tram their machines regularly and for some part I make I do it on lathe and mill ay my factory because its the only way I can assure guaranteed precision.

Takes me many hours but its worth it to have parts precise, bearings slide on axles perfectly, parts all fit together spot on. no gaps and misalignment and the whole machine they belong to works better and last longer.

Automated machines needs to be calibrated and tramed regularly or they will do worse than doing it by hand machining.

.

post #19 of 19
Quote:
Originally Posted by primoz View Post
 

Skismoke when we were talking about machines here it wasn't about machines ski services have in their shop, but about handheld machines like Trione and similar.

So sorry....My Bad! I'm new to this and I guess I got a little anxious to participate. I'll pay more attention next time!

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