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DIY shims for backfiling?

post #1 of 8
Thread Starter 

I have a 2-degree side edge file guide and would like to shim it to use with a panzer file for backfiling. I've read about using duct tape and dimes but wondering if anyone has really found a good reliable shimming method for this purpose. Also, how thick should the shim ultimately be (a question for someone who is better at math than I am)?

post #2 of 8

http://www.artechski.com/artechfileguides.aspx

 

Save yourself the guesswork and the hassle.

 

Artech makes a 7 degree for $22.00 for that very purpose!

post #3 of 8

Super accuracy is not as critical for cutting back side walls as is consistency and minimizing over cutting, IMO. There a zillion ways someone can cut plastic and metal and setting angles. Side wall removal is not right up there with brain surgery or fine craftsmanship or the level of accuracy desired for edge sharpening, but a proper tool is more desirable. Different people have different acceptable tolerances. Having said that, I've free handed with a panzer and sand paper when in a pinch and short on time. (I also have a lot of experience working materials by hand and feel comfortable controlling cutting tools by hand for these purposes.) I prefer a nice sharp planer, followed by sand paper, however.

 

Since the main objective is to remove just enough side wall material and smooth it out, you need to simple rotate the cutting tool in the guide a few degrees so the edge cutting tool (especially diamonds) can cut the edge and not plastic or composite side wall material. Depending on the geometry, the 'shim' thickness is variable, and can easily be calculated.

 

Rise over run = Tan of angle. Measure the shim thickness, distance from guide 'corner' to shim 'corner' where the cutting file rests and divide into the shim thickness. The 'inverse'of tangent will give you the angle.......or eyeball it, git 'er done and get out the door. They are your skis.

 

Edit: Here's a Tangent chart. I can draw something after skiing if it'd help.....


Edited by Alpinord - 12/21/10 at 6:43am
post #4 of 8
Quote:
Originally Posted by Alpinord View Post


 

Rise over run = Tan of angle. Measure the shim thickness, distance from guide 'corner' to shim 'corner' where the cutting file rests and divide into the shim thickness. The 'inverse'of tangent will give you the angle.......or eyeball it, git 'er done and get out the door. They are your skis.

 

Edit: Here's a Tangent chart. I can draw something after skiing if it'd help.....


 

 

I was told there would be no math.....biggrin.gif

post #5 of 8
Thread Starter 
Quote:
Originally Posted by ZeroGravity View Post

I was told there would be no math.....biggrin.gif


I also was kind of thinking that the answers would be more along the lines of "cut a credit card in half and use it as a shim" or something like that. Of course, Alpinord did say "...or eyeball it, git 'er done and get out the door" along with a very technical answer.

post #6 of 8

Contrary to apparent popular opinion here, backfiling is not done to remove sidewall material. That is what a sidewall planer is for.

 

Backfiling is to blend the top of the side edge into the sidewall after planing the sidewall.

 

That is why Backfiling guides are 7 degrees. You are not creating a 7 degree side edge bevel you are blending the exposed top of the edge into the sidewall to reduce drag.

 

After using the Panzer at 7,  I then use it 1 degree over my final edge angle. So if I want a 3 degree I would file with the panzer at 4 degrees  until sharp. then switch to a bastard file at 3 degrees to finishh the edge. followed by a 2nd cut file, then a progression of stones finishing by polishing/honing with a True Hard Stone or Arkansas stone which highly polishes and hardens the edge.

 

Remove the hanging burr and no pressure on the edge point with a gummi and you're ready to go!

 

Again, save your self

post #7 of 8
Thread Starter 
Quote:
Originally Posted by Atomicman View Post

Contrary to apparent popular opinion here, backfiling is not done to remove sidewall material. That is what a sidewall planer is for.

 


Again, save your self


Perhaps I am not using the proper language, but Alpinord suggests in this wiki that the panzer file and a high angle edge guide can be used by the casual tuner in place of a sidewall planer:

http://www.epicski.com/wiki/side-wall-planing-and-cutting

 

Regardless, I think your method sounds really good if one has all the tools. I'm just looking for a "good enough" version for right now as I'm a new tuner and have not yet built a comprehensive tool set. I look forward to acquiring more tools in the future. I've read many of your tuning posts and really appreciate guidance. You and Alpinord frequently provide the information that seems most logical to me.

post #8 of 8
Thread Starter 

 

Update: I got out some practice skis tonight and put the panzer file in my 2-degree guide with a nickel used as a shim to increase the angle. It very cleanly shaved off the sidewall, and then after a few passes I could start to see a very fine shiny line at the top of the edge (the edge was a bit rusty, so it was easy to see when I was starting to hit the edge). I have no idea what the shimmed angle was -- I just used Alpinord's "eyeball it and get 'er done" method. I think I'll use a slightly thinner shim on my non-practice skis in order to remove less sidewall, but this method worked great.
 

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