Knives 3-7: grind question

R

Riddle

Joined
Sep 5, 2015
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14
I've decided to start doing only free handed flat grinds after reading some recommendations, but after doing some research I think I'm more confused than anything.

Here's what I've done so far on Aldo 1084
2s6rnlw.jpg


My question is after you set the initial 30-45 degree bevel and work your way up to the spine, do you ever change your angle, or do you maintain the same angle and remove more and more material the further you go back? My belt began to dull so I think as I walked my grind back I never really flattened the blade.

Also what grind did I achieve by accident?
 
Also just thinking about things and my stock is 5/32" thick.
Blade is ~1.3" wide.

This would give me a blade angle of around 3.4 degrees or 6.8 included angle which from what I understand would be entirely inappropriate for 1084 / anything other than something for slicing correct? So I should leave it as is?
 
This always seems to be difficult for new makers to understand because we tend to overthink it. The angle is whatever it takes to get from the edge to the spine. You can do the math and figure it out but it's not necessary unless you are using a jig. Your process is fine. Use belts like they are free. Once it stops cutting well get a new one. There are places for worn out belts but bevels ain't it! If the grind gets near the spine and the edge is too thick then start back at the edge and work your way back up. Repeat until it's right.
 
What you got was a convex grind. Not really so bad if both sides are the same. You did say your belt was getting dull. That was one of the reasons this has happened. Someone long ago said "use belts as if they are free" in fact that's very close to the truth. If you had used more sharper belts, it would show you if you had to change your angle or not to get a flat grind continuos top to bottom.
I hope it goes as you want next time but it ain't all that easy for most of us to learn.
Frank
 
Thank you Matt and Frank, this clears it up quite a good bit. I may just leave this and get new stock that will give me a better angle for a ffg.
 
You can FFG really any stock. Just don't grind all of the way to the spine. Leave at least a little "J" there. It looks better.
 
If this isnt already heat treated you may want to leave it. I find I have a lot more control over my flat grinds on hardened steel.go back after and clean it up if you wish.
 
It has not been heat treated. Also my tip broke off, it wasn't much and it seemed like it discolored at that point. Would it be my angle being too small or the heat buildup?
 
Likely it was too thin if it snapped right off. The more experienced here can correct me but towards the tip (especially with a dropping point) if you keep the same angle that you have at the heel you are going to grind that sucker into oblivion.

I have to rotate the blade subtly as I get to the tip to avoid that. Even so, with something like a broad sandoku you have to be really careful or you will have something weak and paper thin before HT even. From what I hear grinding a dagger this applies as more obviously. If you kept the same angle the whole time you wouldn't even have a tip.

Concentrate more on what you want your edge thickness to be and where you want your grind lines, distal taper and plunge lines (or just distal taper and plunges with a FFG) and the angle ends up whatever it ends up.
 
Here is a diagram I made for another thread a while back about "progressive angle grinding". I learned about this from a thread by Fred Rowe. Aside from it being a good and efficient technique, it also helps you understand a bit of what's going on while grinding when you're first starting out, at least it did for me.

progressive%20angle%20grinding%20steps_zps8nr2ftfk.jpg


~Paul
My YT Channel Lsubslimed
... (It's been quite a while since I've posted any new vids)
 
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