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First DIY tune, no hanging burr?

post #1 of 20
Thread Starter 
Did my first DIY tune on some older atomic SL12s. Side edge: Deburred, 100 diamond, filed to get new metal and get the edge uniform 3 degrees along the edge then 200, 400, 600, 1500 diamond and hard stone to polish. Removed 'hanging burr' with a gummi at 45 degrees with NO pressure. Side edge had a mirror finish like no ski edge I've ever seen and looked great. Bases are flat and base edge is 1 degree, it has some scrapes but I only deburred it with an alu oxide stone - nothing else. Skiing they were improved but really I expected better hold on hardpack from a slalom ski. After skiing on them for a few days I did 400 to 1500 and hard stone polish with no 'hanging burr' removal at all and the skis were no different and no 'hanging burr' effects when skiing - have I tuned these correctly?
post #2 of 20
Quote:
Originally Posted by narc View Post
 Skiing they were improved but really I expected better hold on hardpack from a slalom ski.


Sounds like you did everything OK (except for /gummi/ to deburr instead of hard stone). 

 

How many days skiing are on these and what was the problem?  

 

If you are comparing grip to when they were new, it may just be that they are flexed-out.

post #3 of 20
Thread Starter 
Quote:
Originally Posted by cantunamunch View Post



Sounds like you did everything OK (except for /gummi/ to deburr instead of hard stone). 

 

How many days skiing are on these and what was the problem?  

 

If you are comparing grip to when they were new, it may just be that they are flexed-out.

I bought these used since they will be left out in a ski property abroad where snow coverage isn't great, no idea how many days have been on them, they have some gate damage on the tips so probably a few but they feel ok. I'm comparing to an identical pair I have that are almost new but have not done back to back tests due to locations so it is hard to be sure - I don't remember having too much trouble with hardpack on the new ones out of the wrapper and with the old but tuned ones I have having to be very careful with my edge pressure to avoid the ski blowing out of the carve on hardpack. Even skidded turns sometimes the outside ski would slide out a bit. Maybe these skis have just seen better days, does some reduction in flex really have that much of an effect on edge grip?

post #4 of 20

Assuming same boots, and same binding geometry on the two pairs,  then the problem is either in the flex or with the base edges.   

 

The only further thing to try would be a base grind to flat and a re-bevel of the base edge.    If that doesn't fix the problem - sell 'em to a tourist.

 

post #5 of 20
Quote:
Originally Posted by narc View Post

I bought these used since they will be left out in a ski property abroad where snow coverage isn't great, no idea how many days have been on them, they have some gate damage on the tips so probably a few but they feel ok. I'm comparing to an identical pair I have that are almost new but have not done back to back tests due to locations so it is hard to be sure - I don't remember having too much trouble with hardpack on the new ones out of the wrapper and with the old but tuned ones I have having to be very careful with my edge pressure to avoid the ski blowing out of the carve on hardpack. Even skidded turns sometimes the outside ski would slide out a bit.Maybe these skis have just seen better days, does some reduction in flex really have that much of an effect on edge grip?

 

yes!     the SL12 is from about 4 seasons ago.  If they have had a couple of seasons of gates they will definitely be softer and have lost some bite
 

 

post #6 of 20

If this was your first DIY tune, I'd give the skis the benefit of the doubt and consider that maybe your first attempt wasn't fully up to snuff.  Do you have a friend who knows how to tune who can take a look at your methods?  An elaborate series of stones is all fine and good, but won't guarantee good results if you don't use them right.

 

Tuning isn't hard, but it's easy to end up with a crap tune if you don't know what you're doing.

post #7 of 20
Thread Starter 
Quote:
Originally Posted by DanBoisvert View Post

If this was your first DIY tune, I'd give the skis the benefit of the doubt and consider that maybe your first attempt wasn't fully up to snuff.  Do you have a friend who knows how to tune who can take a look at your methods?  An elaborate series of stones is all fine and good, but won't guarantee good results if you don't use them right.

 

Tuning isn't hard, but it's easy to end up with a crap tune if you don't know what you're doing.



Unfortunately not, the skis are out in Bulgaria and the reason I needed to start to DIY tune is that getting any kind of reasonable work done on skis there is next to impossible - if someone has heard of waxing skis you are lucky, I had one guy (apparently an ex racer) refuse to believe skis had base edge bevel. I even went into a ski shop and asked for some wax and they took out a candle and looked confused.

This is mostly why I'm posting here, to see if anyone might know why the result is as it is, if anything could have gone wrong because there doesn't seem to be any evidence when skied of a hanging burr being present. Is there any particular technique for diamond stones? I found it hard to know when I was done with each grit and did 4 passes slightly overlapping with a very small amount of pressure. The filing was done with a medium file and it took quite a bit of work to get the edge a consistent 3 degrees and I had to use quite a bit of pressure.

post #8 of 20
Quote:
Originally Posted by narc View Post

Unfortunately not, the skis are out in Bulgaria and the reason I needed to start to DIY tune is that getting any kind of reasonable work done on skis there is next to impossible - if someone has heard of waxing skis you are lucky, I had one guy (apparently an ex racer) refuse to believe skis had base edge bevel. I even went into a ski shop and asked for some wax and they took out a candle and looked confused.

This is mostly why I'm posting here, to see if anyone might know why the result is as it is, if anything could have gone wrong because there doesn't seem to be any evidence when skied of a hanging burr being present. Is there any particular technique for diamond stones? I found it hard to know when I was done with each grit and did 4 passes slightly overlapping with a very small amount of pressure. The filing was done with a medium file and it took quite a bit of work to get the edge a consistent 3 degrees and I had to use quite a bit of pressure.


The technique is mostly about how you hold the file/stone & guide so you don't round off the edge, but if you forgot to plane or backfile the sidewall, that would cause sub-par results.  You shouldn't have to use much pressure on the file though, especially if you hit the edge with a diamond stone first to remove any work-hardened sections; something seems funny.  The best you can probably do in the absence of a skilled assistant is watch this video, and pay attention to how he does everything:

 

 

Also, while you're in self-diagnosis mode, your edge should feel sharp after each step you complete.  Once you're done filing (and deburring from that), check for sharpness.  Go to your diamond stones next, and check sharpness after each one.  That might help you narrow down where you're going wrong.

 

Good luck!

post #9 of 20
Thread Starter 

Thanks Dan. The skis did need some sidewall planing to start (did it with a swix planer) any removal of sidewall rather than edge was very easy to feel. I'll give the video a watch and check the techniques, unfortunately my season is done now so I'll have to wait until next year to see how the skis do with any changes.

post #10 of 20

The video guy's saying that 89, 88, 87-ish are normal angles. My edge guide says it's a 92... is it actually 88? It looks like it creates an acute angle on the edge, so I'm guessing it's really 88? Also is that the same as saying it's a 2 degree edge angle?

post #11 of 20
Quote:
Originally Posted by Metaphor_ View Post

The video guy's saying that 89, 88, 87-ish are normal angles. My edge guide says it's a 92... is it actually 88? It looks like it creates an acute angle on the edge, so I'm guessing it's really 88? Also is that the same as saying it's a 2 degree edge angle?

It should all be the same.  The "video guy" is one of the best, and has tuned for WC racers.

post #12 of 20
Quote:
Originally Posted by Metaphor_ View Post

The video guy's saying that 89, 88, 87-ish are normal angles. My edge guide says it's a 92... is it actually 88? It looks like it creates an acute angle on the edge, so I'm guessing it's really 88? Also is that the same as saying it's a 2 degree edge angle?

 

They're all different ways of saying the same thing.          _/_  is 88 degrees on one side, 92 degrees on the other, and 2 degrees from being a perfect right angle.  We call a perfect right angle "0 side bevel"

post #13 of 20

Thanks :) I wasn't sure if 92/88/2 were the same, or if I was creating some kind of weird anti-performance edge with the tool... (which is still possible I suppose, but that would be user error rather than tool design)

 

Who is the guy in the video? It was helpful!

post #14 of 20
Quote:
Originally Posted by Metaphor_ View Post

Thanks :) I wasn't sure if 92/88/2 were the same, or if I was creating some kind of weird anti-performance edge with the tool... (which is still possible I suppose, but that would be user error rather than tool design)

 

Who is the guy in the video? It was helpful!

  Willy Wiltz...former service man for Bode, Rhalves, and many others...I've watched these before and enjoyed them. Lots of good stuff (talks kinda loud though...)

post #15 of 20

  BTW...in these vids Willy presents his method for removing the burr...as soon as I watched, I switched to his method. Works great, but takes some time...

post #16 of 20

Very cool--thanks

post #17 of 20

They will only feel sharp between passes if yopu dry them first. I have a rag at my bench (Cotton terry) and always dry everything off before I feel the edge. Also I don't like the goo from the last stone pass sitting on the edge wewhen I change to a finer stone. (probably overkill, I know) but if you try to feel the sharpness when the edges are wet they will not feel sharp.

 

Also folks are getting confuesd between a hanging burr and the edge point burr and how to feal with them.

 

Hanging burr removed with arkansas stone flat against the base edge.  Final pass with gummi with no pressure 45 degrees to edge point.

 

2 completely different issues.

post #18 of 20

Sounds like your ski is not flat.  Most used skis aren't flat edge to edge due to home/shop tuning.  Run a true bar over them and look for a gap between the edge and the true bar.

post #19 of 20

Numbers in the 80's are the angle the ski edge forms.  An 89 degree edge would be formed by a 1 deg base edge and a 2 deg side edge.  To create a 2 deg side edge the edge guide I use is labelled 92 degrees.  If you were using a multituner you would just dial in 2 deg.  But to make matters more confusing I also have, but stopped using, a fixed angle tuner that can be used two ways--one way is labelled 90--the angle of the side edge to the bottom of the ski, and the other way was labelled 88 degrees, which gives that 89 edge angle when the base angle is 1 deg.  But that guide was marketed to snowboarders which is why it makes no sense (sorry, couldn't help myself).  I stopped using it for the obvious reason that I kept using it the wrong (90) way. All of this will be on the test.

 

And wow--1500 grit.  At that point you're not tuning the skis, you're detailing them. I'm impressed.  I use 800 grit stones on my chisels and plane blades and they shave hair. 

post #20 of 20
Quote:
Originally Posted by oldgoat View Post
  I use 800 grit stones on my chisels and plane blades and they shave hair. 

 

Some of the guys in our woodworking club use 6000 grit water stones eek.gif.

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