edge thickness issues

C

Cameron Wilcox

Well-Known Member
I am having trouble grinding the edge on my knife evenly, some parts of the edge are thicker than others. I measured on the three problem points and the thicknesses are from plunge line toward the tip: .0575", .0120", and .0320" is around the usual thickness. The thin area formed when I tried to grind the thick area down.
these are the three points I measured, first two are the problem areas
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This is what I'm talking about
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Don't feel alone. I do that all the time. I'm getting better about it, but it takes time and practice (I know, you hate hearing that, I did...lol) But it's true. I keep my blade moving and hold it in the problem areas a little longer. I can't really explain it, but you'll get a "feel" for it.

One culprit is that you may not be holding your knife at the same angle or near the same angle on every pass. I still have problem doing this. I try and concentrate on keeping all the sparks coming from the center of the belt. This let's me know I'm getting a full 2" grind cross the blade and not grinding on the edges of the platen, which can gouge or "wear" a low spot in your blade.

Another reason may be because the belt makes more contact in the center of the blade. If you grind to the plunge and then back to the tip, the center of the blade is getting more contact. Something to keep an eye on while grinding.

Sorry I can't help more than this. I'm a newbie too it really does take developing a "feel" for it.
 
yeah, I'm starting to wish the learning curve went a little faster. I forgot to mention I don't have a platen so Its all slack belt work.
 
Cameron Wilcox said:
I am having trouble grinding the edge on my knife evenly, some parts of the edge are thicker than others. I measured on the three problem points and the thicknesses are from plunge line toward the tip: .0575", .0120", and .0320" is around the usual thickness. The thin area formed when I tried to grind the thick area down.
these are the three points I measured, first two are the problem areas
View attachment 27674
This is what I'm talking about
View attachment 27673
Click to expand...



It my Book it's OK that there are different thickness's on the blade, As long as they are thickest by the heel of the blade and tapering out to the tip. That's they was it's suppose to be!
The Heel Thickness is for heavier work and it gets finer as you get to the tip!

The Long blade looks alright from what I can see, If you are thinner by the Heel, Than the middle of the blade you need to reduce your Zeal for that plunge cut!

Now that you are aware of this is the bright point here, adjust and be aware of your two hands at the plunge and after!
I still don't always get it right ether, But Knowledge and adjusting is Learning!

Laurence www.rhinoknives.com/
 
I have never ground on a slack belt,so I really can't say,
but my guess would be if I tried to do a flat grind,on a slack belt
mine would not look that good.Good luck.

God bless,Keith
 
I would say the two most likely culprits are
1. Not keeping the blade moving. When grinding it is important to keep the blade moving, I start the blade with the belt in the middle between plunge and tip, with very light pressure. Then all in one motion slide back to the plunge and grind out to the tip. You dont want to work any one part of the blade at a time. Try to think of the blade as one plane that you are grinding. Working one area, for instance the trying to get the plunge just right, while you are working the area you are creating a 2" mark on the blade. This is the point where the edge of the belt opposite the part you are working is also grinding the area you are not concentrating on. Again I try to think of the whole blade as one plane, so if I grind at the plunge I follow that amount of grinding through the tip. Keeping the bevel even.
2. You could be putting more pressure on one end of the knife without knowing it. This can cause dips from the edge of the belt digging into the metal. Try to make sure your hands are "locked in". I lock in my elbows and forearms to my hips and move my whole body from side to side.
As for that blade, you could just grind the edge profile back some and even out the thickness.
Hope this helps.
 
Good tips from Sean about grinding. I've watched both Harvey Deans and Jim Crowell's video's on grinding. Both have great tips. I like Harvey's probably the best but Jim covered the thing about locking your arms to your side and moving back and forth. Just tried it yesterday and it was amazing how much more control I had. I'd also suggest learning to control the blade with the hand that is holding the tang. I was trying to control the pressure with the hand holding the blade to the belt (my thumb most of the time). After watching these two video's they talked about controlling the blade with the hand holding the tang. It worked very well and now my grinds are much better.

Just some food for thought.

Oh, the best thing that has helped my grinding by leaps and bounds was taking the work rest off of my 2x42. Now I can get close and see the blade much better.
 
Cameron Wilcox said:
I forgot to mention I don't have a platen so Its all slack belt work.
Click to expand...

In my opinion, lack of a platten is a large part of your current problem, especially if you are just learning to grind. Learning to grind WITH a platten can be a challenge. Trying to fight a flopping belt and keep things even would multiply the learning curve tremendously.
 
I taught myself how to grind "Slack belt" Convex Grind.
What Sean is saying about learning to have the hand holding the tang is On The Money.

Then the other hand follows and steady's in the pass From Plunge to about 90%. I leave a chunk on the end and finish up the tip after H, Treat. I get the point I want much more often, The steel is hard now and I get a crisp grind & point.

I grind sitting down, I am over 6ft 4" and have several pieces of titanium in my lower Spine. "That's another story"

I have much better control for me sitting and leaning forward can put my elbows on my knees to steady things.

So Cameron, What kind and size belt machine are you using? Standing or sitting?

You can make truly great working knives Convex grinding. When done right, You have a continuous graceful curve that includes the edge. These are also referred to as a Bullet grind, Like a spritzer FMJ .308 ...

Laurence

www.westsidesharpening.com
 
Well I guess it's a single speed? Lots of people make knives with them but I could really see and feel the diff when I fitted my
Coote Grinder with step pulleys.

If yours is a single? Could you get at the drive and motor spindles to put on step pulleys?

Slowing down helps alot when learning and in general.

Laurence

www.westsidesharpening.com
 
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