how to get definative bevel grind lines

E

elvenbladesmith07

Joined
Jul 29, 2004
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663
im curious as to how you guys get such nive bevel grind lines on your knives. do you have a special jig or platen? i usually just angle grind the rough forged bevels, and then us a belt sander with a convex piece of wood slipped under the metalic flap(underneath the belt). but on my blades i cannot see a distinctive line. usually i like this but for my WSK, i want to be able to see the grind lines. any suggestions? tools are; angle grinder, belt sander, bench grinder, old rotary tool from the 50's, a random orbital sander, assorted files, and a forge. keep in mind i can make any "platen" from wood, but id isnt as distintive as it looks under the metal flap and the belt of the belt sander. thanks for the help guys!
 
elven,

You may be learning the best way, by not using optimal equipment for the job. I suggest using no jigs, even though I do use one for delimiting the plunge lines :o . I think most us are using 2 X 72 belt grinders with hard flat platens or hard rubber booted wheel platens. I suspect the wooden platen you are using may be contributing to not getting crisp deliniations. On the other hand I am not sure I understand enough about your equipment to say definately. For crisp grinding think hard and consistant platen. I think most of the guys are doing their convex grinds either on slack belt areas of the grinder or by using platens with give.

RL
 
i have a rockwell belt sander, not a belt grinder. it has a rubber covered motor driven wheel at one end, and a steel wheel at the other. in between there is a very thin, very flexible steel flap, with foam underneath, that gives the belt a smooth, flat surface to slide across. i slip a convex piece on wood as a platen under this flap, and it makes a hump in the belt instead of it being flat. this is what i use for trueing up my hallow bevels. i figured i would explain my sander in better detail for you so it makes it easier to understand. if you still dont understand ill have a freind take pictures of it and my knives and maybe that will help. just tell me if you dont get what im talking about RLinger, ill try and clear it up. i realize my problem is hard to explain without a picture. sorry about that.
 
Well it sounds like you are getting good hollow grinds with it. Is that correct? Is it flat grinds you are having difficulty doing with the grinder?

RL
 
yeah the grinds are even and deep i just want that definative line between the flat and the top of the bevel. that part is always rounded off. so i cant tell if the blade is hallow, convex, or full beveled unless i hold it and look at it.
 
Maybe someone else can give better advise but I am thinking it is because of the platen - as I was speaking of above.

RL
 
Its quite possible RLinger. Ill try a diffrent platen. I really have to post a pic so you guys can understand my question better.
 
I think I know what you are describing for your set up. Getting a nice definitive grind line is one of the harder parts of a hollow grind. More difficult for me is getting my plunge cuts even. I use an eight inch serrated contact wheel on my 2 x 60 Burr king. Better to learn how to grind freehand than to use jigs. Jigs can't handle contoured blades well.

I start out by beveling my edges at a 45° to about center line of the blade's edge, then work on moving that bevel line up into the spine of the knife. With practice, and by no means am I an expert, you will get them even and sharp. Once you get the holloe started, a slight upward pressure will move your grind line up and make it sharp. I have ahd it happen a few times in my lifetime, but it is still hard to do for me.

I think what has been said is true, you need a consistant flat/contoured surface to grind against and practice, practice, practice. I am still trying to get it right.

On another note, what is harder for me to do is keep the sharp grind line that I get from the belt grinder during hand sanding a hollow grind. They always tend to get a bit washed out for me. It still looks sharp, but that is just me taking off the etch......The pictues below show the whole story:

f7.jpg


f2done.jpg
 
Why sure Elven, I wouldn't mind my bevels looking like that too. Should I begin to think your bevels are not as rounded as you lead us to think, I wonder. Perhaps you are doing better with that piece of wood than you say. Kidding aside, try a strip of graphite on your wooden platen. Pop's sell them and it is not a big price and it will easily contour to your platen. You can use regular ol gum glue to attach it. I wonder about the flexable stock platen that came with the machine. Did you say it was rather flemsy? If so that may well be the main cause of your problem. In grinding, even though it may not be noticed by you, the belt could be forced convex. That will round flats in an instant. A solid replacement platen made of thicker steel and mounted more securely by you is a solution.

RL
 
well my platens never get worn down since they are never in contact with moving belts. the are covered by that thin flap of steel. and i dont use a jig just to let you know. i always free hand it. what you wer saying about losing the line during hand sanding is what im talking about, i never get a line, mine are always rounded over. when there roughly forged, when there ground in, when theve been belt sanded, and when they've been finished, the lines are never there. i think i need to do less grining with an angle grinder and use more of the belt sander and have a platen shaped exactly like the bevel i want. usually i just use the convex piece of wood to get out the deep grined scratches, i think i need to start actually using the belt sander for bevels.
 
I use A/O belts, I have not seen where the ceramic ones last long enough to warrent the price. One thing I do to try to keep the gring line sharp during hand sanding is to work the flats last and heavy. Get out all the scrathes from the lower grits from the hollows and then work on the flats. that will tend to sharpen things up.

Dude, no offense meant here, but you can only do so much with that grinder. A 1 x 42 or a grizzly set up would probably be better than what you are using. Unfortunately equipment does matter to a certain extent. I still whish I had a KMG. Maybe Santa will bring me one, but I better not hold my breath. ;)
 
believe me, if i had any money at all, i would buy a belt grinder first :D , i think im stuck with what i got(which really stinks :mad: !). could i convert, or build a belt grinder pretty cheaply?
 
If you are doing convex grinds, you are not going to have sharp grind lines. The grind flows from the edge to the spine. Just like a flat grind only with more thickness to the blade. The hollow grind shows the grind line the best.
Scott
 
That's the same thing I've used. What a PITA! I did however grind a "Busse" 5160 7 in. blank with that thing and use a bastard file to help clean up the edges to make them cleaner.

Good luck :)
 
just a modest suggestion but you must have a better grinder. To that end, I'd say make what your equiptment will allow, and make it good!! Neck knives, or something with 3" blades or there'bouts where you can be proficient. Sell your knives and save every penny for a Grizzly 2x27 and repeat the process. You'll have a KMG in no time! :)

regards, mitch
 
In my experience (13 years in a handmade production shop) bad lines are caused by "rolling over" your line once it is established. If you are using a concave grind on your bevel try making a sanding block out of micarta slab, say 1/2 x 2 x 5. On one end grind a radius from one side of the flat to the other and when you are hand sanding wrap the block with your sanding paper/belt. Clamp the blade flat, securely to your bench with the edge facing you, you might have to put a pin or block behind the blade to keep it from sliding. Then, using the radius on the sanding block, sand the bevel rightup to the line but do not go over the line (Believe me it is easier said than done). Likewise when you sand the flat you should sand toward the line without rolling over it but you must also remember to not roll over the edge between the back and flat. The "trick" is to sand/polish toward the line, defining it more and more with each step in the process, while keeping the line "straight".
 
anvilring said:
just a modest suggestion but you must have a better grinder. To that end, I'd say make what your equiptment will allow, and make it good!! Neck knives, or something with 3" blades or there'bouts where you can be proficient. Sell your knives and save every penny for a Grizzly 2x27 and repeat the process. You'll have a KMG in no time! :)

regards, mitch
Click to expand...

I think Mitch speaks from experience. He also turns out some really nice work. He might sell one now and then too if he woudl respond to emails.

You ever goign to send me info on that pistachio knife?

Doc
 
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