Grinder Stock Removal

GWashington1732

GWashington1732

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Jun 20, 2009
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I was reading a knife making book and from what I understand, the blade can be shaped through stock removal using a grinder instead of a band saw. Is this a practical method or did I read it wrong? Is this a lot more difficult than using a band saw?
 
A 40 or 50 grit belt at high speed will go through steel like it was made of toilet paper, profiling a lot faster than a bandsaw. The downside, for me, is the dust it creates, so I get as close as I reasonably can before grinding.
-Mark
 
grinders are pretty quick, but belts can get pricey, band saws take a little bit longer but the blade last longer, you might get 2 profiles per belt, and probably 8-10 with a good bandsaw blade.
 
What polish avenger said.

I did this series of blades all out of S30V about 5 years ago. I was cutting them out with the band saw and then getting down to the actual profile line with the belt grinder in about 15 minutes. Then one day for kicks I just ground one out ONLY using the belt grinder... got it shaped in 5 minutes.

But for me, the extra wear and tear on the belt grinder, and mostly the dust, just wasn't worth the difference.

Also keep in mind we're talking about a 1-1/2 hp 2X72 belt grinder (Burr King).
 
Most bench grinders are not even going to approach the metal eating ability of a knife quality belt grinder.

Of course there are exceptions... At the local school they have a 3hp Baldor pedestal grinder with 2 X 12" grinding stones. It will eat steel like nothing I've seen. But that's a $500 unit IF you can find a good used one... I think they're about $3000 new. You'd be MUCH MUCH better to spend $3k on a fully loaded, 3hp KMG. :)
 
I shaped several large blades with a bench grinder before I got a real belt grinder.. They were 1/4" A-2 and 5160. It can be done but the wheels glaze up with metal and you need to dress them to be able to cut efficiently again. I wouldn't want to do it again with steel that thick, but it can be done. You can build up a lot of heat and work harden some steels if you don't dunk it in water once in a while.

I took off the bulk of the excess steel with an abrasive metal cutoff blade I mounted one end of the grinder. I bought an extra set of metal spacers from Sears for $3 to hold the cutoff wheel tight. You will catch the wheel if you are trying to make a longer cut and don't keep it perfectly straight. It is also an exposed saw blade. Now I use a 4" hand grinder with a metal cutoff wheel to remove much of the excess and it works pretty well.

I wouldn't want to profile a knife out of 3/16th" or thicker if I couldn't cut off some of the excess first. It takes a long time with a bench grinder but it's not terrrible. I was concerned about safety after reading that those vitreous grinding wheels can come apart and cause bad injuries. You might consider buying a Norton wheel instead of using cheap chinese ones like I did. Wear a face shield if you have one.
 
I like the 36 grit Blaze for profiling. I can usualy do 8-10 blades with one belt. Average blade is 9" long 3/16" material mostly D-2. It's definately faster and good bandsaw blades are not cheap even if you cut and weld your own.
 
I used a metal cutoff blade on a bench grinder for years before getting a band saw. It's nasty work, but it does work pretty well.
 
Before I started forging, I shaped my first 7 or so blades with a side grinder, bench grinder, and files... slow going, generates tremendous amounts of dust and heat, but it does work.
 
Personally i think that it's cheaper to use a metal cutting bandsaw to profile a knife rather than using belts. A good bandsaw blade from Lenox will cost around 25 bucks or so (the cost of 5 belts maybe) and be able to cut out dozens of blades whereas the belts *might* profile out 5-10 blades depending on size and thickness of material. .25 and up even a 40 grit belt will slow down *eating metal* compared to a bandsaw blade with lubricant.

This is assuming you're using nothing but a belt grinder to profile the blade

just my $.02 :D
 
I cut my blanks pretty close on the bandsaw and then clean up the profile on a disc grinder. Then I go to the belts and start working on the rough grinds before heat treating.

I rough grind everything to 60 or sometimes 120 grit and then heat treat. I finish grind down to at least 600 grit or 2000 grit if I am going to mirror polish the blade.
 
Goodness. I remember trying to profile a blank when I first started using a little bench grinder. I quickly stopped. Too much noise, too much vibration, too much ... well, annoyance. I just used my 2x72" Grizzly, but that went slowly with the cheap belts I was using, so I got a 4.5" angle grinder and used that for a while instead.

Now, I get 75% profiled with a bandsaw and angle grinder and then spend just a few minutes at the grinder using 60 grit Blaze belts.

--nathan
 
Stock removal generally refers to grinding the profiles and shape (not necessarily the outline, although it is finished here) rather than forging it out, normally like said above a band saw is used to shape the blank, angles grinders are less common.
 
when I cut knife blades out I use my angle grinder with a cutting blade. I even used a dremel once to cut out a bowie knife from 1/4 inch 0-1 (not recommended).
 
I've done knives both ways - the bandsaw is surely cheaper than the belts, unless you use good belts that are fresh it can take longer to grind in the profile, depending on the shape and the steel. A bandsaw will also allow you to more easily take advantage of plate.
 
I just clamp the stock in my vise and use an angle grinder. I use a $60 ryobi 4.5" and I can do an 8" OAL in less than 10 min. Discs are like $2 a piece and last for a while. I usually get .25" discs to use for grinding and when they get thin I use them for cutting.

Just scribe the line deep enough to see through the color change and you're all good. I've maybe spent $100 over the past 3 years on grinder discs.

Also, with good control of the grinder you can put a very nice hollow grind on a blade using sanding discs. And you can rough profile handle scales. And you can cut things too big to go on a bandsaw.


And as a fun side note my friends made a pitching machine out of two angle grinders and some dumpster wheels and it shot a baseball through a cinder block :)
 
I use worn 36 grit belts. It costs me nothing because they are not good for anything else. With a push stick I can do several blades in the time it would take me to do one on my bandsaw.
 
Hope you don't mind me asking, where can we get the 2000 grit belts like your talking about, I haven't seen many around. Are they available in 2X72

thanks
 
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