"DIY" sharpening of 6" hand auger Lazer/Finbore blades

[Shoe]

Saw a few others asking about sharpening; so, I was reminded of my recent auger sharpening experience.  A couple of years ago, I sent my 6" Finbore-2 auger blades in for sharpening.  They came back and wouldn't shave a lick - couldn't even start cutting a hole.  Company had a 307 in it; but, it happens to all I am sure.  Rather than go back to the sharpener with the problem, I took the issue into my own hands.  I read all the threads on DIY sharpening here at the shanty.  I already had a Lansky knife sharpening kit.  I bought the round stones for it, as someone suggested.  I made a jig to hold the blade.  I figured the angles on both edges, the primary (smaller angle) and shaving (larger angle).  I put new edges on the blades that didn't cut - via Lansky knife sharpening methods.  I had low expectations.  But, to my surprise, the blades cut a hole like new.  Since then I have touched up the shaving edge another time with the same great results.  I just re-sharpened the shaving edge of another set of dull blades that I had.  Next time, I may have to do the primary edge because there is still some waviness to the shaving edge.

My point is just to give an idea of how these curved blades might be sharpened.  Not trying to put sharpeners out of business.  Sending or taking these curved blades to a quality sharpener still might be cheaper, easier and better. I just wanted another option...and I like it.

Below are the photos of the jig at various angles with Lansky stones.  I am sure the jig can be improved upon.  If any of the pros have suggestions for improvements, please fill me in.  Jig is wood with a stapled plastic sheet cut from a milk carton.  I cut the grooves in the plastic with a wood burning tool.  Disregard my messy work bench.  Measurements are on last photo.

s

[struckus]

I use a cotton wheel on a bench grinder with #6 polishing compound..basically hones the bur off the edge making the blade sharp again without getting into the factory edge..surprising how sharp it gets after a few passes..

[grumpy grandpa]

shoe, is there a reason you could't use the the lansky jig?

[Shoe]

shoe, is there a reason you could't use the the lansky jig?

I couldn't get the Lansky knife holder to hold the curved blade so that I could get the same angle all the way along the blade.  With some shims and correct positioning of the blade in the Lansky holder, it might be possible to get the angle right to touch up the shaving edge.  I don't have a solution for that approach; maybe you or someone else does.  The shaving edge, as you know, is the very tiny barely visible edge.  It is critical for cutting a hole.  I don't see how the primary (obvious, main) edge could be sharpened in the Lansky holder because the angle actually changes depending on location along the blade.  This custom jig allows attempting to sharpen that one, too if necessary. 

s

[Huntindave]

I couldn't get the Lansky knife holder to hold the curved blade so that I could get the same angle all the way along the blade.  With some shims and correct positioning of the blade in the Lansky holder, it might be possible to get the angle right to touch up the shaving edge.  I don't have a solution for that approach; maybe you or someone else does.  The shaving edge, as you know, is the very tiny barely visible edge.  It is critical for cutting a hole.  I don't see how the primary (obvious, main) edge could be sharpened in the Lansky holder because the angle actually changes depending on location along the blade.  This custom jig allows attempting to sharpen that one, too if necessary. 

s

Looks like a good working prototype jig.  One thing you might consider is a more stable "saddle" for the blade to sit in.  You could make a bed of most anything which would set up and harden.  Wax or other "mold release" to keep the material from sticking to the blade.  Place a gob of bedding material on your board, screw the blade in place, let the bedding material harden.  Now you have a positive, stable "saddle"  for the blade to sit in when being sharpened.   

Then again, that may be overkill and not absolutely needed. 

[SteveTheChimneySweep]

Could you make a new board? the blade could be fastened to the board as in your jig, then the board clamped to the lansky.

[FreshwaterPhil]

I've been sharpening my fin bore blades for years. All I use is a pen style diamond hone sharpener. I keep one in my tacklebox as well as a wrench, I done it out on the ice a couple times after hitting bottom. They cut like new by the time I'm done.

That being said, not all curved blades are the same. For the life of me, I can't sharpen a Nils on my own 

[earlyrise]

Good info TY