I am trying to learn how to do hollow grinds ive been doing convex grinds and put my 10 inch smooth contact wheel attachment on . Can someone give be basic tips. I know nothing never even seen a blade ground so I would really appreciate any help. Right from is the cutting edge ground up or down, Ive a kmg clone if your wondering what im using. kellyw
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HOLLOW GRINDs
- Thread starter hellgap
- Start date
- Joined
- Jul 20, 2007
- Messages
- 3,121
Did you watch JT's video? http://www.jtcustomknives.com/videos.htm
Nathan the Machinist
KnifeMaker / Machinist / Evil Genius
Moderator
Knifemaker / Craftsman / Service Provider
- Joined
- Feb 13, 2007
- Messages
- 19,125
Cutting edge up.
Scribe the lines that represent your finished edge thickness onto the edge of the stock. Start the hollow at the edge and bring the grind close to the scribed center lines. Then work the hollow up the edge bevel towards the spine. Pay attention to how you hold the blade with the strong hand to be sure you're holding it the same with the weak hand.
Keep the blade moving and flat to the wheel or you will get divots.
When you lay the blade to the wheel, try to lay it on as flat and even as you can, but err on the edge side. You will feel it find the hollow.
Dull belts and high pressure tend to grab the blade and move it around, causing facets.
Most people pull the handle out away from the wheel a little bit as you get to the belly and tip. I turn the blade to keep the edge perpendicular to the wheel as I go around the belly, but not everybody does it that way.
Scribe the lines that represent your finished edge thickness onto the edge of the stock. Start the hollow at the edge and bring the grind close to the scribed center lines. Then work the hollow up the edge bevel towards the spine. Pay attention to how you hold the blade with the strong hand to be sure you're holding it the same with the weak hand.
Keep the blade moving and flat to the wheel or you will get divots.
When you lay the blade to the wheel, try to lay it on as flat and even as you can, but err on the edge side. You will feel it find the hollow.
Dull belts and high pressure tend to grab the blade and move it around, causing facets.
Most people pull the handle out away from the wheel a little bit as you get to the belly and tip. I turn the blade to keep the edge perpendicular to the wheel as I go around the belly, but not everybody does it that way.
- Joined
- Nov 24, 2007
- Messages
- 952
http://smartflix.com/store/video/275/The-Fine-Art-of-Hollow-Grinding cost 10.bucks to rent
vern
vern
- Joined
- Oct 22, 2007
- Messages
- 123
Smartflix is great as long as you don't want Johnny or the original copyright owners to share any of the rental fee. I was going to use them until I Googled them and found out that they don't pay copyright or usage fees to the original owners. While this apparently is legal, they seem to be more willing to share the rental money with their defense attourneys rather than with the original pricipals of the DVDs they rent out.
So no Smartflix for me.
I can't hollow grind to save my ass. I've only ground 3 knives so far though. I get horizontal angle lines running the leangth of the blade and can't get rid of them. I end up grinding too much of the edge preheat-treat and have to grind off some of the edge, leaving me with not enough belly to my blade. Also, can't keep the grind even at the top. Instead of a striaght line where the grind meets the flat part near the spine, my line is all effed-up.