One way to grind a tip

Nathan the Machinist

Nathan the Machinist

KnifeMaker / Machinist / Evil Genius
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Knifemaker / Craftsman / Service Provider
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Feb 13, 2007
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I think this is a clever idea, so I thought I'd share it.

I think most people grind their profile first, then the bevels. I find it difficult to feel the center of a hollow grind at the tip because there is very little blade out there. Add to that the bend of the belly and the tip is pretty challenging (for me anyway). So I re-orded my operations to "do away with" the tip.

For this blade I worked out the knife design in the computer, started the profile, "set" the bevels on the mill and did my grinding. After grinding I then finished the rest of the profile. So, except for the little bit of finish grinding after HT, this knife (with a fairly pointy tip) required no real tip grinding

The blade on top is a "before". It becomes the blade on the bottom. The tip turned out *perfect*


knife_before_and_after.jpg
 
Cool, I normaly don't hollow grind, but I do tend to leave a little extra length on flat and convex grinds so I can get the point rite and not screw it up.
 
Great idea, I really like it and I like drop points an your general design good thinking. Thanks Jim
 
Do you have a picture of what you mean by "set your bevels" with the mill?? I would be interested in what that looks like and what it entails...
 
Peldor said:
I was going to ask the same thing. :confused:
Click to expand...


I don't have a picture of me milling on the bevels on this knife, but the idea is pretty simple.

I set the blade edge up in a mill vice, held in an area that isn't removed. I develop a tool path on the computer model and apply that tool path to the part.

Here is a picture of a bevel being completely machined on the mill. All I had to do was sand it.

blade4_making_blade.jpg


I personally prefer a ground blade to a milled blade, so I just started the bevel on the mill. This gets the thicknesses where I want them and even. I can then finish the blade on a 10" wheel.


This is probably not the most practical way to go about this for everybody, but it works well for me. We all have different backgrounds, so we will all approach this a little differently. I figure someone who is a dentist would probably do some really killer engraving...
 
Holy Mole, Nathan! You are squared away with the machinery! Jeez, and I'm thinkin' that it's too expensive to drop 1700.00 on a Bader grinder. :D
 
Nathan the Machinist said:
I think this is a clever idea, so I thought I'd share it.
Click to expand...

Thanks for sharing that tip. When I get some time back in the shop, I'm certainly gonna give your new method a try. It looks like a winner!

It always amazes me how open we all are here when it comes to new ideas. I wish it were like that in my "Day" job.
 
Nice job. Your comment about backgrounds is so true. Naturally you approach the work as a machinist, some as welders, some as dentist, and others as mechanics. The great thing is we share and get a variety of ideas and methods. There is more than one way to skin a cat. The true test is in the end product. Jim
 
Nathan, the jig that is holding the blade is on an angle right? so you have to reverse the blade to make the mirrored pass?
 
I like your thinking Nathan,

Cant tell you how often I am thinking that the back of my mind while grinding: " one slip and that point is gone" Its great when people think out the box.

Thats also a really neat, practical design your working on there too. I'm busy on a similar design but slightly more of a drop point.

What thickness do you grind the edge to?
 
I am repearing my knives tips like that.:o I never thought about profliling after grinding. Cool idea, thanks. :)
 
Wow, I step away for a day (some of us have day jobs!) and I have half a dozen comments from around the world. Wow.

Troop,
I'm wanting a nice grinder too, but as they say, wish in one hand and...
I didn't get these machines for knife making, but since they're their...

Tanguay Custom Knives wrote,
"It always amazes me how open we all are here when it comes to new ideas"

You folks have taught me a lot, I'm glad I can give back a winner

Peldor,
"Nathan, the jig that is holding the blade is on an angle right? so you have to reverse the blade to make the mirrored pass?"

It is a regular flat square vice and a regular flat square end mill. I created a 3D CAD model and applied toolspaths to it in CAM that run on a CNC mill. The cutter cuts one side, then the other, in many fine passes, in the same setup. I can go into more detail if anyone is interested.

Lang,
Thank you. I've taken them to .030. Likely closer to .025" when all done.
 
Great post Nathan! That is a perfect illustration as to why not buy the smallest milling machine available. You may think you will just do guard slotting but then you run across something else only to discover your guard slotter is too small.
 
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