4 1/2'' Grinder for doing blade grinds?

smitty0331

smitty0331

Joined
Dec 5, 2006
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Hello everyone, I was just wondering if any one has ever tried using a 4 1/2'' angle grinder to start their grinds. I know it would be alot faster than doing it all with a file, but I don't want to do something that is going to cause a problem later on. I know I'll have to finish the grind with a file and sand paper, but couldn't I at least "rough it in" with a grinder?
 
Sure you can............

There is someone here (Knifemaker87?) who loves his right angle grinder. He does all kinds of tricks with it. He even made a jig (or is it a fixture? I never remember) to allow him to control the angle of attack.

I, personally, find right angle grinders a tad fast ( when something goes wrong, or you just get distracted for a sec, you never know until it's wayyyyyyyyyyy too late to correct. All those RPMs at work, I guess ) for most things I do.

Syn
 
There are a few people doing it, but I'm with Syn in that it's too fast for me. You may spend more time cleaning up the grinds with a file than you would just filing them in to begin with. In my opinion, it's harder to flaten with a file on a grosely uneven surface.

Also, as I've mentioned before, you will always be filing steel so it's a skill to always improve. The angle grinder is probably just going to be a stepping stone to a real grinder, in this application, and the skill will quickly become obsolete.
 
It is doable. Like was said, you won't save much time. On soft steel, I think it is a wash on a thinner blade. I am pretty handy w/ one from other trades, and it didn't save me any time on an 1/8" blade.

I did think it made a difference on a 5/16" thick knife I tried to make. That is a whole lot of filework. You will be making a hollow grind w/ it, then flattening it out w/ files. Keep an extra new wheel to make things flatter after the roughing in, before you start filing.

For a thinner knife, you are better off w/ a file.
 
Im also part of the angle grinder brigade. I think its very versatile tool and its easy to use because you can see whats happening to the blade as you are grinding. Like syn and other posts above say, it is very quick, but if stock removal is your purpose, that what you want anyway. Discs outlast belts by far as far as im concerned. I made a jig for grinding with my grinder ( I am sure the idea is not unique, but I havent seen any tut on making one, so I made my own. You can take a look here if you want: http://myhome.mweb.co.za/~20022586) Because it is fast you have to be weary of overheating, but in anycase its a good idea to stress relieve before HT anyway. My first little experimental knife I did in my jig I ground it hard and hot, and without stress relieving I still didnt get warpage with the HT (maybe I overheated both sides equally!!) One cool thing too is that if you tilt the grinder you can get hollow grinds quite easily.

Lang
 
For what it's worth, I'm not sure if you can the grind a true hollow grind... not saying you can't either. The angle grinder will get your steel hot, but I don't think it will get any hotter than some of the blades I've seen ground on a 2x72, I wouldn't worry about that particularly, as long as you're grinding before HT ;)

Many people here don't understand where I'm coming from, so I'll tell a short story. I started making knives on a budget, when I decided to make knives I was in college, paying for my own place and making below the poverty line. I ordered 20' of steel from Admiral and bought some cheapo files from Wal-mart. Trying to file half-hard steel with cheap files just about made me give up on knifemaking. Then I bought a 4x36 and really thought it was an improvement. I saw all of these guys telling folks you need to buy a real grinder or just use files and I would argue against it. I could do it with a belt sander... files sucked, I knew as much, I'd bought a set and failed with them... Well, it turns out that I was wrong, and it took all of two days in another knifemaker's shop to know it. One day showed me why my 4x36 would never be a "grinder", the second showed my why good files kick the crap out of cheap equipment. Now, seeing as how I wouldn't listen to anyone, I don't expect anyone to really listen to me (although I still prattle on).

We all have to work within the limitations of our tools. For me... I'd rather take the slow route and have fewer limits. If I just sat down on a weekend and ground as many blades as I could in a day, I wouldn't even know where to start working on them.
 
I hear exactly where we coming from Acrid. I think we all are somewhat biased toward a specific process based on our experiences or similar reasons. A grinder is what I have/had and I have been happy with the results and like the versatility it offers.
I have regularly used grinders in metalwork and portable beltsanders for woodwork, and I have found belt sanders inefficient and more costly to operate.

Most of us start on some sort of budget with the expectation that if we prove good enough we will invest more in the required tools. Thats the place I am at at the moment. When I have done the bevels with the grinder, I still consider it 'rough cut' and then finish off with belt sander/file/abrasive paper. Much the same way as the guy using a belt gets the shape and profile with course grit and then progresses to smoother grits to final finish.

You are dead right Acrid.. in pretty much every respect its more worthwhile buying quality tools.

By hand there is no way I could do a proper hollow grind, but with the jig coupled with a certain range of blade curvatures, it holow grinds pretty well. On a straight blade it wouldnt work.

Lang
 
I use an angle grinder for almost all my knives. I use a simple bench grinder to grind in the initial 45 degree bevel, then an angle grinder to rough out the grind, and finish on a belt grinder to true things up.

It may be fast, but angle grinding out all that steel is backbreaking, loud & dirty work. Sometimes I'd rather go slow just for that reason
 
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