Freehand sharpen a knife using abrasives coated golf balls

[BluntCut MetalWorks]

For fun

I freehand sharpened a petty 10cm long in 15N20 steel (band-saw) using 1 golf ball coated with Silicon Carbide powand another coated with dust from an Aluminum Oxide stone.

Thanks for watching.

[video=youtube_share;ywewjUEBn7Y]http://youtu.be/ywewjUEBn7Y[/video]

 

[Skimo]

Not available on mobile devices.

 

[9blades]

Not available on mobile devices.

Yup...

 

[BluntCut MetalWorks]

Not available on mobile devices.

Congrats on your 3K post!

I posted early before the video avail because I was about head out the door but need to wait for someone. I will remove the eta line from my original post in a few minutes.

edit: Sorry, video is 95% processed seem stuck there. I'll be back in 2hrs.

edit2: video is now avail

 

[HeavyHanded]

When this discussion first came up I thought 'why not just put the ball on the table, slide the knife right up underneath it, and either work it laterally or slowly roll it along the table with the bevel pressing against it. these pics show a grinding wheel, but it could just as easily be a sphere. Imagine rolling the wheel (sphere) clockwise as you follow along with the blade. I'm surprised it actually works pretty well as long as the table is smooth...

 

[BluntCut MetalWorks]

When this discussion first came up I thought 'why not just put the ball on the table, slide the knife right up underneath it, and either work it laterally or slowly roll it along the table with the bevel pressing against it. these pics show a grinding wheel, but it could just as easily be a sphere. Imagine rolling the wheel (sphere) clockwise as you follow along with the blade. I'm surprised it actually works pretty well as long as the table is smooth...

HH - Thanks for excellent idea. My first reaction was now you tell me, I need this fu-move earlier

So, shooting for smooth push cut. I hovered the blade about 2mm above the table surface - blade stay flat to ensure same angle heel to tip = well, dumb because I destroyed the edge in a few strokes. I used diamond plates to re-create push cutting edge. 2nd try with the AlO ball, this time I lay the blade on the table (blade thickness about 1.5mm). After laterally and while rolling (simulate edge trailing) rubbed both sides = it won't even fast slice phonebook paper. Use techniques in video for 2 minutes before the blade slice phonebook paper again.

Closely look at edge to ball surface is about 30* for a golf ball with diameter around 45mm. Tangent angle is in mid 20*. Even though I used low pressure, look like the edge dug into the abrasive and rounded it. Yes rounded, not burr or roll. Perhaps we need a rotating ball and with diameter greater than 10cm to sharpen a knife blade hold in static position.