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Back Filing

post #1 of 22
Thread Starter 

This has probably been covered before, but I wanted to spread the knowledge.  Today, I discovered the magic that is back filing.  So first, I made sure that I filed away as much of the sidewall as possible, using a sidewall remover.  Then, I took a coarse (100 grit) diamond stone and put it in a multi-tuner set at 5 degrees.  I then started grinding my side edge (back and forth until it felt smooth).  I then took my file, put it on a three degree side edge guide, and proceeded to set my side edge.  The file cut a lot smoother than it normally does, since I was working with an edge that had been over-beveled.  I then continued with a progression of diamond stones, all at 3 degrees.

 

I found that I was able to create a much sharper edge using this method.  And I wanted to share it with those who may not have known about this before.

 

So basically, I have discovered that the keys to sharp edges are 1) making sure you file away as much of the side wall as possible and 2) back filing

 

 

 

post #2 of 22

What effect, if any, would this have on the longevity of the ski edges, since it seems that you would be removing extra surface material each time it's done?  Is this something that you do every time you tune, or just once in a while?

post #3 of 22

You are basicallly trying to assure that there is not a conflict between the cutting tool's ability to cut and polish the edge only. By cutting back the side wall material periodically with a more aggrssive tool than your maintenance diamonds or stones, it should take many times before needing to do periodic side wall removal.

 

Here's the Side Wall Planing And Cutting Wiki.

 

HTH

Terry

post #4 of 22
Thread Starter 

 

Quote:
Originally Posted by Alpinord View Post

 

You are basicallly trying to assure that there is not a conflict between the cutting tool's ability to cut and polish the edge only. By cutting back the side wall material periodically with a more aggrssive tool than your maintenance diamonds or stones, it should take many times before needing to do periodic side wall removal.

 

Here's the Side Wall Planing And Cutting Wiki.

 

HTH

Terry

 

I think it's more than just sidewall removal.  When you back file, you are removing the part of the edge that's closer to the topsheet.  That way, when you go back and file at 3 degrees, all the cutting action of the file is focused on the part of the edge that's closer to the base.  And that's where you want it to cut cleanly.  I have found that this results in a much sharper result.

post #5 of 22
Thread Starter 

 

Quote:
Originally Posted by BillT View Post

 

What effect, if any, would this have on the longevity of the ski edges, since it seems that you would be removing extra surface material each time it's done?  Is this something that you do every time you tune, or just once in a while?

 

The amount of material removed is determined by the tool you use.  Diamond stones remove very little material, and so if you only use diamond stones to do your back filing, it should be ok.

post #6 of 22

 

Quote:
Originally Posted by mrzinwin View Post

 

 I think it's more than just sidewall removal.  When you back file, you are removing the part of the edge that's closer to the topsheet.  That way, when you go back and file at 3 degrees, all the cutting action of the file is focused on the part of the edge that's closer to the base.  And that's where you want it to cut cleanly.  I have found that this results in a much sharper result.

 

From the Wiki (and our tuning tips):

 

post #7 of 22

Huh...sounds pretty cool.  Has anybody else done this?  Are any of the WC techs doing this?

 

post #8 of 22

 

Quote:
Originally Posted by SkiRacer55 View Post

 

Huh...sounds pretty cool.  Has anybody else done this?  Are any of the WC techs doing this?

 

 

A WC race tech showed it to me so yes. I do it on my own skis and even my kids little 105cm twintips so yes. I pull the sidewalls, then I use a big fat bastard file on a 5 degree guide and then a milder file on 3 deg. (2 for my kids skis). Then stones. So yes again.

post #9 of 22
Thread Starter 

 

Quote:
Originally Posted by Alpinord View Post

 

 

 

From the Wiki (and our tuning tips):

 

 

Nice diagram, but it's not exactly what's happenning when I back file.  Normally, the sidewall is already completely removed by the sidewall remover.  The purpose of backfiling is to file down 80% of the edge (the part that's closer to the sidewall).  So imagine in the diagram that the sidewall is gone, and the file is cutting only into the edge.  This leaves 20% of the edge exposed to be cut cleanly with file at 3 degrees.

post #10 of 22
Thread Starter 

 

Quote:
Originally Posted by SkiRacer55 View Post

 

Huh...sounds pretty cool.  Has anybody else done this?  Are any of the WC techs doing this?

 

 

Well, I found it on this website, so---yes.

 

http://www.edgewiseskitunes.com/masters.html?sp=24

post #11 of 22

Cool...I'm going to go give this a try tonight...watch this space...

 

post #12 of 22

 

Quote:
Originally Posted by mrzinwin View Post

 

 

 

Well, I found it on this website, so---yes.

 

http://www.edgewiseskitunes.com/masters.html?sp=24

 

Ha. That's the guy that showed me. Just picked up my Head SS Magnums from him. They had 2 degree base bevel from the factory. I think they're gonna feel a little more precise tomorrow.

post #13 of 22

 

Quote:
Originally Posted by SkiRacer55 View Post

 

Cool...I'm going to go give this a try tonight...watch this space...

 

 

He said, dripping with sarcasm.

post #14 of 22


 

Quote:
Originally Posted by Alpinord View Post

 

 

 

He said, dripping with sarcasm.


 

Hey, it sounds reasonable...our snow has been super hard lately, and we're training full length GS on the  steep tomorrow, so watch for a report...oh, around 1 pm, RMDT....
 

 

post #15 of 22

This is how I have done my skis for years and have posted this from the Holmenkol site at least 10 times.

 

I take issue with using a diamond stone for back filing. that is just a waste of time. Since diamond Stones just polish they don't cut! I use a coarse diamond on the side edge set to match the side edge as a first step just to make sure there are no burrs or case hardened spots before I use a file.

 

You should back file with a short Panzer file at 2-3 degrees over your final edge angle maybe 2-3 passes is all that is neede. In fact Artech makes a 7 degree inexpensive side bevel tool for this purpose.

 

I then use the panzer at 1 degree over my final bevel angle. So if I want to end up with a 3 degree Use a 4 degree side beveler & the panzer until the edge is sharp. 

 

I then go to a 3 degree with a short Swix or Holmenkol 13 TPC Bastard file and file until sharp. (I do not use chrome files, don't like 'em)

 

You can then go to a short 2nd cut 15-18 TPC file followed by a series of stones. Depending on the ski. I first use a 200, 400, 600 and then a True hard Arkansas stone for final polish. (for Gs, SG DH you can go

to 1000 & 1500 if desired)

 

Once final polish is done I use a green FK/SKS fine Green gummi at a 45 degree angle down the edge with absolutely no pressure whatsoever.

 

Last step is to remove hanging burr from all the side edge activity with an Arkansas stone flat against the base edge with medium pressure from tip to tail. Be sure to be in constant contact with base edge and not roll  the stone over the top of the side edge.

 

If you want a copy of this or want to read it yourself it is here:

 

Step #8!!!!

 

http://www.holmenkol.net/myadmin/datafiles/techimages/Prepping%20Your%20Skis.pdf

 

 

 

 

 

 

 

 

post #16 of 22
Thread Starter 

 

Quote:
Originally Posted by Atomicman View Post

 

This is how I have done my skis for years and have posted this from the Holmenkol site at least 10 times.

 

I take issue with using a diamond stone for back filing. that is just a waste of time. Since diamond Stones just polish they don't cut! I use a coarse diamond on the side edge set to match the side edge as a first step just to make sure there are no burrs or case hardened spots before I use a file.

 

You should back file with a short Panzer file at 2-3 degrees over your final edge angle maybe 2-3 passes is all that is neede. In fact Artech makes a 7 degree inexpensive side bevel tool for this purpose.

 

I then use the panzer at 1 degree over my final bevel angle. So if I want to end up with a 3 degree Use a 4 degree side beveler & the panzer until the edge is sharp. 

 

I then go to a 3 degree with a short Swix or Holmenkol 13 TPC Bastard file and file until sharp. (I do not use chrome files, don't like 'em)

 

You can then go to a short 2nd cut 15-18 TPC file followed by a series of stones. Depending on the ski. I first use a 200, 400, 600 and then a True hard Arkansas stone for final polish. (for Gs, SG DH you can go

to 1000 & 1500 if desired)

 

Once final polish is done I use a green FK/SKS fine Green gummi at a 45 degree angle down the edge with absolutely no pressure whatsoever.

 

Last step is to remove hanging burr from all the side edge activity with an Arkansas stone flat against the base edge with medium pressure from tip to tail. Be sure to be in constant contact with base edge and not roll  the stone over the top of the side edge.

 

If you want a copy of this or want to read it yourself it is here:

 

Step #8!!!!

 

http://www.holmenkol.net/myadmin/datafiles/techimages/Prepping%20Your%20Skis.pdf

 

 

 

 

 

 

 

 

 

sweet post, atomicman

 

though you certainly have spent a lot on tuning equipment!

post #17 of 22


 

Quote:
Originally Posted by mrzinwin View Post

 

 

 

sweet post, atomicman

 

though you certainly have spent a lot on tuning equipment!

......spending a lot on tuning equipment...think of it as an investment, because now you don't have to pay a shop to do it, and you can do it the way you want...over and over.  I think Atomicman has the Full Monty on backfiling; I did a short form that seemed to work also.  I use an FK Swing Cut for side edge work, which is nice because you can set the bevel angle from 1 to 5.  I have one Swing Cut loaded with an Arkansas stone on the front end and a tungsten carbide file on the back end.  So I do the edge at 5 degrees with this, then I have another Swing Cut with two ceramic stones, so I do the edge at 3 with this.  Yeah, I know...it ain't the full Monty, but it still seems to work.  I've used this setup training SL, training and racing GS, and I like the extra stick I seem to get out of the edges...
 

 

post #18 of 22

Good summary Atomicman,

 

I am a newbie at tuning, but everything you said makes sense. I use a fine diamond stone to remove the hanging burr as I can easily control it without dulling the edge. But I don't quite understand the gummi stone with "absolutely no pressure". Is that your first fling at trying to remove the burr or make it less than razor sharp. OTOH, with "absolutely no pressure", I know I am being a bit overzealous here, I would hazard that it would do nothing but remove any filing material on the edge. Can you clarify? I have used the gummi stone to reduce the edge a tad and the tips and tails with very "light pressure".

 

Nick

post #19 of 22

There is always microscopic metal particles (burr( on the edge after filing and polishing the side edge. Not a hanging burr The 45 degree does not have any effect on the hanging burr. the no pressure Gummi makes the actual edge point super super smooth.

 

Yes a very fine diamond is perfectly acceptable to remove the hanging burr, but I prefer an Arknasas stone.

 

Taking some sharpness off the edge takes a bit of rubbing the gummi back and forth with a slight bit of pressure. So you only want to do this if you find your skis hooky or grabby but a better solution is ever slightly more bevel in the tip and tail

 

From The Race Place www.ski-racing.com website and Scott Holmer inventor of The Beast tuning gear:

 

 

Deburring


Gummy Stone After filing/polishing edges you should deburr with a gummi stone.  Lightly run along edge at 45° angle to remove burrs.  DO NOT DULL!!


Edited by Atomicman - 3/16/2009 at 11:47 pm
post #20 of 22

I'm going to have to read this at home since I can't see the diagrams at work...but maybe someone can answer a question.

 

Is what's being described as back filing here akin to putting a micro-bevel on a chisel or plane blade (i.e. - where you shape your blade with relatively rough grit to flatten, remove chips, and establish the primary angle, then set a secondary angle that's a couple degrees higher than the primary, so you arent' fine sharpening the entire cutting face of the blade)?

 

So back filing a ski edge, you're saying you put a more acute angle on the whole edge, then when you do your final sharpening you change the angle so your tool isn't cutting the entire edge face, but just the small part of it (essentially ending up with an edge that has two bevels -- the initial angle that is far from the snow, and the final angle that creates the edge that touches the snow)?  Or are you setting the initial angle, then resetting the entire edge face to the final angle?

post #21 of 22


 

Quote:
Originally Posted by billyymc View Post

 

I'm going to have to read this at home since I can't see the diagrams at work...but maybe someone can answer a question.

 

Is what's being described as back filing here akin to putting a micro-bevel on a chisel or plane blade (i.e. - where you shape your blade with relatively rough grit to flatten, remove chips, and establish the primary angle, then set a secondary angle that's a couple degrees higher than the primary, so you arent' fine sharpening the entire cutting face of the blade)?

 

So back filing a ski edge, you're saying you put a more acute angle on the whole edge, then when you do your final sharpening you change the angle so your tool isn't cutting the entire edge face, but just the small part of it (essentially ending up with an edge that has two bevels -- the initial angle that is far from the snow, and the final angle that creates the edge that touches the snow)?  Or are you setting the initial angle, then resetting the entire edge face to the final angle?

 

Since the angle of the new bevel is less then the backfiled edge it reduces the entire edge to your final bevel angle.

 

So, it changes the entire edge angle.

 

Side edge bevel angles can be increased or reduced at will unlike base bevel abgles, which can only be reduced by stone grinding the base but can be increased at will.


 

post #22 of 22

I have a reprint from an old issue of Ski Racing of a more detailed article by the same author. If anyone is interested, just send a PM.
 

 

Quote:
Originally Posted by Atomicman View Post

 

This is how I have done my skis for years and have posted this from the Holmenkol site at least 10 times.

 

I take issue with using a diamond stone for back filing. that is just a waste of time. Since diamond Stones just polish they don't cut! I use a coarse diamond on the side edge set to match the side edge as a first step just to make sure there are no burrs or case hardened spots before I use a file.

 

You should back file with a short Panzer file at 2-3 degrees over your final edge angle maybe 2-3 passes is all that is neede. In fact Artech makes a 7 degree inexpensive side bevel tool for this purpose.

 

I then use the panzer at 1 degree over my final bevel angle. So if I want to end up with a 3 degree Use a 4 degree side beveler & the panzer until the edge is sharp. 

 

I then go to a 3 degree with a short Swix or Holmenkol 13 TPC Bastard file and file until sharp. (I do not use chrome files, don't like 'em)

 

You can then go to a short 2nd cut 15-18 TPC file followed by a series of stones. Depending on the ski. I first use a 200, 400, 600 and then a True hard Arkansas stone for final polish. (for Gs, SG DH you can go

to 1000 & 1500 if desired)

 

Once final polish is done I use a green FK/SKS fine Green gummi at a 45 degree angle down the edge with absolutely no pressure whatsoever.

 

Last step is to remove hanging burr from all the side edge activity with an Arkansas stone flat against the base edge with medium pressure from tip to tail. Be sure to be in constant contact with base edge and not roll  the stone over the top of the side edge.

 

If you want a copy of this or want to read it yourself it is here:

 

Step #8!!!!

 

http://www.holmenkol.net/myadmin/datafiles/techimages/Prepping%20Your%20Skis.pdf

 

 

 

 

 

 

 

 


 

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