 Poster: A snowHead
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It's an old non-SH thread but a couple of things made me ponder:
1) "The only way to sharpen base edges for most people is to grind the base. At some point, edges become rounded enough that just sharpening from the side doesn't work. Or, you'd have to take away alot of metal on the side to get through the round part. So it makes more sense to grind it." - I'm not sure I am understanding the logic of this - can someone enlighten me?
2) "Edges, and the ptex next to the edges, wear with use on abrasive snow (all snow is abrasive to some degree), so in order to get a ski flat and the edges sharp, the non worn down material toward the middle of the ski has to be removed." Is this correct. Will all bases become convex over time if you don't have a grind?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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No and yes, sort of. The linked thread is talking about machine grinding which removes, almost by design, more of the base material and therefore the edge metal, than is usually needed, so will certainly limit the life of the ski compared with doing it manually.
But to your points
1. Your wording does not really make sense, no, particularly the bit about getting through to the round part. It's perfectly possible to sharpen the edge base without doing a full grind, with decent tools.
2. In principle yes, the rounding of the base, or more accurately the edge becoming more worn down than the base, will occur over a few services, but not really in general use if you don't often resharpen them, and tend to lift the edge from the snow surface. I don't think the bit about abrasive snow is relevant.
I do most of my own ski servicing, using a file to scrape the base material level with the edges from time to time. Removes much less than a machine grind, although the latter may sometimes be indicated if there's an accumulation of damages which will tend to leave the base less and less flat and even over time.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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Stoning a base is for introducing structure onto the base. It will also flatten it in the process. I was taught to base file skis then do the base edge then structure them then do the side edges. Well the 000's of skis I did were all done like that and seemed to be ok 
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So my point about 1 is that my understanding is that base edge will be 0.5 or 1 degree as if the edge is totally flat it can catch. And that you leave the base alone unless absolutely necessary. How does then sharpening the side edge end up "round"?
And my interest in point 2 was the abrasiveness of the snow causing the base to become convex. It was the first I'd hear of this. @Chaletbeauroc, if you never touch the base edge but just sharpen away the side edge how does that change anything in terms of the base and edge contact with the snow?
All of this ultimately is about the need to base machine grind which I've always thought was avoidable with good by hand servicing. I've had my skis quite a while and never had them ground.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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@Layne, why so scared of the base edges? Mine usually look like they’ve been gnawed by a bear by the end of the season, and I’m pretty careful about not skiing rocks. Those burrs need smoothing out and the edges polishing up to get them sharp again, and any nicks in the bases need tidying up, otherwise they will catch. I’m not changing the angle, it stays at 1 deg, then service the side edge and remove the hanging burr that forms towards the base. Sharper than a sharp thing if you do it right.
I’ve never needed to base grind my skis, as I don’t think convex bases is a particularly common problem. I guess most skis will do it eventually, but you probably need to hang on to them for quite a number of years, or be unlucky with the manufacturing. I will probably move mine on before they get to that point.
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@Scarlet, I was mainly talking about the angle. I am pretty light with them though. Just running a file down.
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On my dry slope skis I did notice that the bases had worn more than the edges leaving the edges proud like rails. The plastic bases wear more than the steel edges. TBH I should have them base gound to remove the proud edges but the edges were getting pretty thin by then anyway.
Just a question @Layne, what base angle to you set your edges to? I do 1 degree and 87 for the sides.It works for me.
Perhaps having my bases ground would improve my performance, but I suspect better technique would yield better results
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Had this before. As they were dedicated dry slope skis that were pretty trash I just left the edge proud, which I was convinced at the time gave me more edge grip, particularly as my edges were sharpened away to an very thin strip by this point. I did once ski on snow with them like this and were animal, hooked up all the time, but lethal when you needed to skid....
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You'll get to see more forums and be part of the best ski club on the net.
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| Layne wrote: |
So my point about 1 is that my understanding is that base edge will be 0.5 or 1 degree as if the edge is totally flat it can catch. And that you leave the base alone unless absolutely necessary. How does then sharpening the side edge end up "round"?
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I don't know, but your 'understanding' about leaving the edge base alone seems odd, as I said I do sharpen mine with no problem, so the roundness thing doesn't seem clear.
| Layne wrote: |
And my interest in point 2 was the abrasiveness of the snow causing the base to become convex. It was the first I'd hear of this. @Chaletbeauroc, if you never touch the base edge but just sharpen away the side edge how does that change anything in terms of the base and edge contact with the snow?
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That's not what I do, but if there is a marked convexity the ski is not going to sit flat on the snow, so regardless of the edge angle you cut the ski will have to be tipped over by a degree or so before the edge properly makes contact with the snow, meaning that the effective angle of the edge will be lower when it catches,
| Layne wrote: |
All of this ultimately is about the need to base machine grind which I've always thought was avoidable with good by hand servicing. I've had my skis quite a while and never had them ground. |
Sure, but you seem to be basing your questions on the assumption that without a machine you can't do a base grind. Which is not true, as several others have now also said.
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| johnE wrote: |
| Just a question @Layne, what base angle to you set your edges to? I do 1 degree and 87 for the sides.It works for me. |
I don't have a base edge angle instrument so they are left at factory setting. Most are set to 1 when I checked online.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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| Chaletbeauroc wrote: |
| the roundness thing doesn't seem clear. |
Yeah to me neither - hence I thought I'd ask on here.
| Chaletbeauroc wrote: |
| Sure, but you seem to be basing your questions on the assumption that without a machine you can't do a base grind. Which is not true, as several others have now also said. |
That is true. I didn't think you could do a base grind without a machine. Just to be clear I mean base not base edge. Maybe I missed it but how do you do a base grind without a machine?
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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If you look closely a ski edge actually has two angles shown below
Normally we only ever need to tune the side edge with a file to keep edges sharp.
The base edge / bevel is (generally) left untouched when hand tuning.
However, it is not completely square. Primarily to make release from turns easier to initiate.
After a lot of skiing the (several hours on dry slope or a season on ice) the base edge "bevel" can become rounded.
In this scenario the edge can't be properly re-sharpened simply by file-ing side edge.
You need to reset base angle - either using a base edge guide or with a full shop tune.
When you get a ski ground the shop shaves a few mm off the base of the ski.
This allows them to use a machine to reset the base and side edges.
The edges will feel razor sharp - however I tend to prefer hand tuning.
If you take off too much base material then skis dont last as long and become more prone to core-shots when hitting rocks etc.
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I have never seen a machine take a few mm off the base. Even with multiple passes on a belt (what shops with no grinder use) you are only removing fractions of a mm from the majority of the base. If you are needing to take a couple of mm off you should be getting better at filling and scraping repairs. Even with dry slope race skis that had fairly frequent trips to the belt I have never seen skis with the bases gone before the side edge is too thin.
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You know it makes sense.
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@Chris_n, Over-servicing can be a real problem with rental skis, particularly at the higher end, like race skis, where performances is key and special rental-specific versions don't exist. But you're right, "a few mm" is far more that a machine grind should ever remove, probably by an order of magnitude, given that the edge is itself only a few mms thick.
I bought some ex-rental race slalom skis a year or three back, cheap enough and I knew what I was getting, was more like an extended demo, but they'd had a couple of seasons' use and there was really not very much thickness of metal left on the edges. Lasted me a couple of seasons, then were replaced by a current version of the same ski and could really see just how much base/edge had been removed over time.
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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| Chris_n wrote: |
| I have never seen a machine take a few mm off the base. Even with multiple passes on a belt (what shops with no grinder use) you are only removing fractions of a mm from the majority of the base. If you are needing to take a couple of mm off you should be getting better at filling and scraping repairs. Even with dry slope race skis that had fairly frequent trips to the belt I have never seen skis with the bases gone before the side edge is too thin. |
Entirely fair point.... Few mm's is exaggeration.
Though shop base grind definitely makes the bases of skis thinner.
Especially if done regularly.
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Poster: A snowHead
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A guy popped up on one of our local ski groups asking for recommendations for a shop to do “this year's” base grind. Apparently he had it done every season. I asked him what kind of rocks he liked to ski  He didn't seem to realise it was a bit of a fringe approach!
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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As I was just saying on another thread here, if you ski off piste most of the time you hit lots of hidden rocks so need frequent repairs. In my experience most shops seem to finish a repair with a grind.
And yes, my bases are very slightly concave, but doubt this matters.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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@snowball, Not quite sure how you'd get concave bases...
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Nore do I@Chaletbeauroc. It is under 1mm and only the section near the bindings.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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| snowball wrote: |
| Nore do I@Chaletbeauroc. It is under 1mm and only the section near the bindings. |
Are you sure there is not some delamination / swelling of a wooden core etc going on. It is more usual to get the shovel / tail going convex than the area under the binding unless there is something else going on.
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@Skiyeah, I know some guys putting a distinct burr on their race skis. They bite so hard they have to have a run off area to bleed speed.
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@Chris_n, swelling would make it convex. Wear makes it concave.
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| snowball wrote: |
| @Chris_n, swelling would make it convex. Wear makes it concave. |
Not necessarily (even though I mistakenly said convex when I meant concave), I have had skis where one of the edges delaminated. Before the delamination became obvious enough to see a steel scraper placed across the edges showed the bases to be hollow (about 0.5/0.75mm).
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