Platen vs. Contact wheel...Help please

DiverTexas

Well-Known Member
I'm in the process of grinding my first blade.

I have probably read and over read too many tutorials and books for my own good.
There seems to be a vast difference of opinions on how and where to begin grinding the bevels on the blade.
At this point I have used nothing but the platen to try to get my plunge lines and bevel started. I used the contact wheel to shape the handle area and clean up burrs, but nothing else.
I was reading yet another tutorial, and from what I gathered, it sounded as if I should be using my contact wheel in lieu of the platen.

For some specifics, I'm trying to grind a small drop point skinner. I am hoping for a hollow grind, but after chewing up what seems to be an extraordinary amount of steel, I'm thinking it will become a flat grind at the rate I'm removing material trying to perfect my grinding on the platen.
I started out trying to use a table I fabricated, but have since then been doing it free hand.

Any input and direction would be greatly appreciated.
Thanks in advance.

Russell
 
Check out Fred Rowe's video on grinding. There is also a tutorial that he did on KD. I haven't tried this but as Fred shows it it makes sense.
 
I really don't know how you would do a hollow grind on a platen. The palten is generally used for flat grinds or scandi grinds.

FlatGrinding.jpg


SaberGrinding.jpg


For a hollow grind, you are picking up the curvature of the wheel when you remove metal.

HollowGrinding.jpg


If you want a really wide and shallow hollow grind you use a bigger wheel or make two hollow grinds on a smaller wheel and blend them together. For a shorter deeper hollow grind use a smaller wheel.

You can also do a convex grind using the slack part of the belt.

ConvexGrinding.jpg


I hope that helps.
 
Thanks Wayne and Mike.
I'll try to find a link to Freds video and check that out.
The pics Mike posted definitely helped as well.
I will try to get some pics uploaded tomorrow of my destruction so far.
Hats off to those of you who have mastered grinding, it's been a humbling experience to say the least.
 
Hang in there and take your time. Freehand grinding takes practice to get good at it but grinding is my favorite part of knifemaking. Usually anyway. There are days when I can't do a decent grind to save my life so I just quit ruining good steel and go work on handles or sheaths. But when I'm in the groove (literally) that's when it is really fun.
 
Those pics are pretty good but most people grind with the edge up I believe.
I think hollow grinding is the easiest. Once you establish that groove you just stay in it working the grind up the spine. Its like its own little track. Leave enough steel to work your way thru the grits. After 120 grit you will mostly stop removing metal and start blending lines and removing scratches. If you fall out of your hollow onto the flats just hit the flats on a disc sander with 220 and they will clean right up. Keep practicing and you will get it im sure.cool 1
 
I hollow grind free hand edge pointing up and the same if I was flat grinding. However if you use a jig mine grinds with the blade down. I f you think your taking to much metal off to fast then go to a higher grit like 120 that will help things slow down . I start off with 36 and switch to 60 grit after 3 passes each side wit hte 36 then do about 10 to 15 passes with the 60 grit and move on. 120, 220 320. then structured abrasive belts up to 500 before heat treat.
 
Yes. I do most of my grinding edge up too. When I drew those sketches I just thought it illustrated the shape of the grind better to show it that way.

Actually I was taught to grind a secondary bevel first that would set my edge thickness for the rough grind. And I would draw my grind line for the top of the grind. Then, as I was taught, I would grind edge down from the center of the grind to the edge and then turn it over and grind edge up from the center to the grind line.

Gil Hibben has a good DVD demonstrating this technique. I still do it that sometimes and other times I do it all edge up. It just depends on the blade and what feels most comfortable to me.
 
Yes. I do most of my grinding edge up too. When I drew those sketches I just thought it illustrated the shape of the grind better to show it that way.

Actually I was taught to grind a secondary bevel first that would set my edge thickness for the rough grind. And I would draw my grind line for the top of the grind. Then, as I was taught, I would grind edge down from the center of the grind to the edge and then turn it over and grind edge up from the center to the grind line.

Gil Hibben has a good DVD demonstrating this technique. I still do it that sometimes and other times I do it all edge up. It just depends on the blade and what feels most comfortable to me.[/QUOTE

The sketches are great bro! I just wanted him to know how most people do it. Theres prolly all kinds of ways to grind a blade. No right or wrong if the results are what you are after. Your blades certainly speak volumes for your technique.
 
Gentlemen, thanks for the info and words of encouragement.
I guess I was hoping this would be something I could master quickly. It has become clear that this is an art that will require time to learn, much less master.
I may have to concede that I will have to toss some steel away after all.

A couple of pics to show what's going on.

I rough cut and grinded this blank a few days ago.

P1014700.jpg


Since then, I have abused it down to this point.


P1014756.jpg




I'm going to give it a whirl again today and see if I can salvage it and just have a short blade for the skinner.
 
Your starting picture looked good. For a flat grind, what you have to do is gradually (take your time and let the grinder work...dont' force it) work the top of the grind up towards the spine. You do that by putting a bit more pressure on the spine side of the blade while staying on that same flat that you've already ground. Conversely, to thin the edge, you put more pressure on the edge side of the blade. It does help to grind edge up as was said as you can see the contact point of the edge to the belt. Watch that area when you grind to give you better control.

Take heart. That looks alot like my first attempt at bevel grinding. Do a few more (or a few hundred depending on your aptitude :D), and thing will begin falling into place. One of these days, you'll be grinding, and it will "click", and it will seem much easier.

--nathan
 
Take your time. If you start getting frustrated WALK AWAY!!!!!!! Just step back for a few minutes and get your wits about you. It is hard to do but it will help. I have had to learn this the hard way and a bunch of wasted steel.
 
When I first started making knives I used any scrap I could spare and pounded it out then ground the h--- out of it. None of it was good knife steel just something to grind on. Cheap little grinder made it harder to achieve a good grind, but it was practice. I threw away a lot of steel before I got it right.

I guess what I'm trying to get at is it just takes a good technique, determination and a lot of practice and one day you will hit itand there's your blade. Don't get discouraged it will come to you if you want it. Good luck.

Larry
 
My suggestion would be to go to a paint store and get some stirring sticks. Try the grinder on them for a while until you get the feel for what the wheel is doing. Then try it on some iron or cheap low carbon steel that you know you can't make a blade out of. Practice holding the knife edge up in your left hand if you are right handed. When you gain some control over what is going on shift over to the right hand. It will seem much easier. Once you can control the grinds then you can worry about the plunge cuts, centering the edge and the height of the grind. That way what you are doing is learning how to grind rather than trying to make a knife. There is a real distinction between the two and making a good knife will come much faster.

Remember the most important aspect of making a knife is to never let anybody see your scrap box!
 
Harry, I have a drawer whos contents never see the light of day except for on very rare "Show your first knife" posts. :D

--nathan
 
It looks like you ground at too steep of an angle for too long. I did that a few times when I tried to have a higher grind line with being too steep. If you're having trouble with it, you could leave a little extra (1/16" or something) on the edge of the blade when you go to grind, so you have a little room for error before messing up your design.

What I try to do (what I learned from others) is grind about a 45 degree angle, then walk it up the spine (by pushing the blade flatter and flatter against the platen) until the grind is at the desired height. I personally like full flat grinds compared to partial height.
 
Lots of good advice here guys, much appreciated.
I am now truly learning that patience is indeed a virtue.
 
If your having trouble get some cheap mild steel to practice on. The wood can help but it just doesn't have the feel of steel.

Just be patient and it'll finally click. I could tell you how I do it but it seems like everyone has their own way of doing it.
 
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