Bench grinder to profile a knife shape

[yamabushi]

I am thinking of attempting something when I get home from work later on tonight. But first wanted to see if anyone else has tried to profile a knife via a bench grinder. I saw on you tube a knife maker used a belt sander to profile out a knife I was wondering if this would be possible as well with a bench grinder. Just seeing if anyone has tried it and if so..yay or ney?

[Ray Rogers]

Of course it has been tried, and it has been done. There's very little you can think of related to knife making that hasn't been tried. Is it a good idea, does it work well? Not just 'No' but '@#$% NO!'. Anyway, that's my opinion, you can bet there will be others. But, bench grinders are very noisy and rather slow, they generate a lot of heat in the steel, they throw a lot of grit so eye protection is paramount, and in worse case scenarios the stone can fly apart which is, of course, potentially very dangerous.

In my early days I bought one just for that purpose. Used it once, put it away for 12 years until I finally found another use for the motor. Many bench grinders don't cost much but I'd suggest saving the money towards a belt sander ....

[yamabushi]

I actually just picked up a belt sander today from Harbor Freight for 40 bucks. Its 3800 RPM.

http://www.harborfreight.com/1-inch-...nder-2485.html

I noticed the knife maker was using one with 7000 rpm with a 40 grit. I know this one would be slower, but I guess im asking would this one do the job, just a bit slower I assume?

[rockhound]

Hi yama,
I'm also a beginner at stock-removal and still working on my first one. Obviously I'm not very knowledgeable in this dept but can offer my thoughts based on my limited experience thus far.
If you're starting with a billet like I did... there can be a lot of metal to remove to achieve profile. Like Ray said, a bench grinder can do it but not the best tool for the job. I used a 4" angle grinder and achieved profile with ease by clamping the billet to a table. I then took it to the bench grinder to clean up the edges, curves, etc. The bench grinder definitely worked well for that. I was slow and methodical with both tools as not to overheat. I did no quenching, just took breaks as soon as it started to get hot. The annealed billet stayed soft and workable.
Belt grinder would be nice but not necessary (ask Jim Bowie, lol), I can't afford to be in that club yet either.
The rest can be achieved with hand files and sandpaper if one has the patience and tenacity. I actually enjoy hand-working the steel and have learned a lot so far. The fine folk here have taught me much.
Good luck on your build and have fun!

[Ray Rogers]

Yama,

Again, not much you can dream up that hasn't been done. In the case of your 1x30" it was done by me right after I put away the bench grinder. If you are making 3" pen knife or paring blades then the 1x30 can struggle through. Anything bigger than that (which is almost any knife) and you'll quickly find that the machine is way under powered and the belts don't last very long at all. Again, save the money towards a real belt grinder. Focus on 2x72". It doesn't have to be expensive, you can build it yourself as little more than a couple of wheels that will run the belt with at least a 1 hp motor. That will do the job, not the best, but far better than these other half measures. If you aren't able to do that right now then stick with files and sandpaper - you'll need those skills down the road anyway.

Some guys get a little help from other $100 belt sanders that are designed for wood. You already know what my advice would be but it scratches their "I want a machine tool" itch for a while. Other guys have fair luck using angle grinders and they have the benefit of being cheap to buy. Noisy, dirty, very dangerous, but cheap and they will do the job if you spend enough time and material on learning to effectively control it.

In a nutshell I wouldn't worry about power tools for grinding until you are willing to spend at least $600 on a Grizzly grinder. Spend more and get something better if you can but the Griz is a real belt sander and nearly half of all the knife makers in the country seem to own one. It is the most grinder you can get for the money. Not the best, but it's ready to work right out of the box and it really, really does the job ...

[WBE]

A bar can be rough shaped remarkably fast with a bench grinder mounted with a metal cut off wheel rather than a stone. After scribing in your profile, you make a series of straight in cuts to your line forming tabs. You then come back and cut the tabs out with an angled attack. Once the tabs are removed, you clean up with the grinder mounted with a stone. It is messy, loud, and you need eye and breathing protection, but it works pretty well, and almost as fast as a band saw.

[Crex]

Holding back Ray?
Got to agree for the most part. But.....a lot of us have tried it in the past, hence the experience talking here.
Wouldn't be my choice either, as I do most of my profiling, tapering and bevel setting with a hammer. However, it may be the only tool Yamabushi has in hand at the moment and he's got the jones to grind/profile a blade. On that premise I'd say go for it, but pay heed to the precautions and safety issues above. Keep a large bucket of cold water at hand for steel and fingers.

[Longshot]

I may not be the most experienced maker on here, but I can tell you that it is possible to use a bench grinder to do most any of the work you want to get done. However, what the others have said is true, it is very dirty, you will need eye and breathing protection, and unless you want holes burned into your clothes, an apron. I have been using a bench grinder to make my knives for quite a while now and it has worked great for me. Definitely not the fastest thing in the world, but I am not trying to make knives quickly. Also it allows me to take my time and be sure to keep the grind nice and even and not overgrind.

If you do decide to use a bench grinder, just remember to go slow and keep the steel cool as well. Keep a gallon of water near you at all times, and when you start feeling the steel get warm, quench it until it is cold again. As for the stone, never use a damaged or really worn stone. These tend to flake off pieces, which can be quite dangerous. As long as you maintain your equipment, and pay heed to safety precautions you should be fine using a bench grinder.

[Gary Mulkey]

You asked if anyone has used a bench grinder for profiling a blade and the obvious answer is yes but I think that you understand by now that it isn't the best idea. A small underpowered, high rpm machine isn't designed to do heavy grinding and it's easy to get hurt using a machine for something other than what it's designed to do. A band saw (or even a hack saw) will profile a blade as well.

Also, profiling the blade isn't where you will be doing most of the stock removal. How are you planning on doing the bevels? A round grinding wheel has definate disadvantages as it wants to make the grind concave. The size of the wheel on most bench grinders won't even work for a deep hollow grind as it is too small. NEVER AND I MEAN NEVER use the side of a bench grinder wheel in order to get a flat grind. That is asking to get hurt.

I guess that the best answer to your question would be that it's not a good (or safe) method for stock removal. The machine just wasn't designed for that.

Gary