Tips for me... re: Grinding?

Z

z537z

Joined
Apr 14, 2004
Messages
336
I've ground my second knife now, and it's 100 times better than the first. But...

1. I still can't free myself of dips in the blade where the edge of a belt.
2. The round tip of a blade...I can't get it to smooth out really well...certainly not easily. Do you freehand the curve grind, or is there some sort of trick that'll let you "flat grind" a curved section really easily like the rest of the knife?


Can't wait to finish this one, though. It's going to be pretty nice minus a few dings in the blade, which don't matter too much for a user, but hurts my ability to sell a few, ya know?

Thanks for any advice grinder gurus.

_z
 
To reduce the likelihood of edge cuts, keep your thumb over the platen on top of the blade while you're grinding - do not let any pressure against the blade extend past the edge of the platen. Just keep moving the thumb pressure to be centered over the platen as you move down the blade. I'm not too clear on the tip part, but the same method applies. As you move the edge across the platen, use it to "draw" a straight line across the platen where you're grinding. That is, as you come to the curve, let the handle end of the blade drop so that the edge stays perpendicular to the belt's travel. Hope this makes some sense...
 
I'm definitly not a guru but what works for me re: tips, is to kind of pull out on the tang just slightly when you come to the tip and drop it down to follow the cutting edge profile to keep it at almost a right angle.

don't pull out too much though, I've rounded over a lot of tips doing it this way :eek:

I don't know if this is sound advice or not but it seems to be working for me so far.
good luck, Steve.
 
One word of advice is to round off the edges of the flat platten. It helps reduce those nasty dips and gouges. Plattens wear funny too and makes it hard to get both side of the blade to match. I have to resurface mine once in a while. Thats 2 words of advice.
 
Thanks guys.
I think a lot of it's just practice, but I'm learning quick.

I would round off the platen (I've got an aluminum insert that's exactly 2" accross, which is nice), but it helps with plunge cuts for it to be straight.

Round parts are hard, but I think I can do it if I really take it slow. After grinding for a few minutes you just get restless, ya know?

Now I have to hook up a small radius attachment to my motor...I'll post up pics at some point.

_z
 
also paint the sides with black majic marker. Makes it easier to see where the grinder is removing steel. Walk the bevel up slowly. Use sharp belts. ;)
 
I've found that the medium grit belts do a better job, too. A sharp 80 grit AO belt is do-able, but 120 is probably even better (for me, personally). Seems like the abrasive is more evenly spread out.
 
Sounds like you've got a case of "The dreaded two inch disease..." Fortunately there is a cure (and it doesn't even require a vacume pump ;)
When you start your grind at the plunge line, keep the rest of the blade just slightly off the belt (thus avoiding the other edge of the belt digging in while you check your angle etc.) I think most people especially beginners, tend to hesitate for just a sec while they line up with the plunge line, and if the belt is in full contact with the blade, it'll be digging a divot with the other edge....
Add this to all the other advise you just got and just practice, practice, practice. Also visit with other makers, go to hammer ins etc to see in person how other people do it.
Good luck!
Ed
 
I found that too.
I start with 60 and move to 100 after that, before 220 and 400.

_z
 
Steel shows up your mistakes too slow, for me anyway, to learn where you want to make changes in your grinding technique. A lot of people on this forum have suggested using wood slats but I find that using Plexiglas (dumpster diving at a sign shop) showed me the error of my ways much better.
Also as you progress smaller and smaller mistakes will glare at you. The more I learn about this craft or art, the more hand work I do.
Just my thoughts,
Lynn
 
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