Grinding by circular saw?

Vasilli- I've yet to make a knife but have worked with steel and wood both in various other capacities. And I have to say, regardless of how efficient that set-up might be, its one of the most dangerous things I've ever seen. There's enough danger in a shop environment without inviting more upon yourself.

You'll have to take it to a belt grinder anyways to clean up that edge, won't you?
 
roughedges said:
Vasilli- I've yet to make a knife but have worked with steel and wood both in various other capacities. And I have to say, regardless of how efficient that set-up might be, its one of the most dangerous things I've ever seen. There's enough danger in a shop environment without inviting more upon yourself.

You'll have to take it to a belt grinder anyways to clean up that edge, won't you?
Click to expand...

What is the danger? If it is about disc picking the blade - this magnets are very strong and I can not imagine this happen with cut-of disks.

What else should I pay attention too?

Thanks, Vassili.
 
If you have faith in the magnets and that the disc won't shatter then go for it. I wouldn't myself. I've had cut-off discs shatter on me before when doing something I shouldn't have been doing with them. I don't care who you are, it'll make you step back and take a deep breath.

You'll have to clean it up with a belt or by hand anyway. If it was me, I'd stay as safe as possible and just do the whole thing that way.


what rpm does that saw run at anyway? amd what size/brand disc are you using? Its almost a guarantee that the saw spins a lot faster than the disc is rated for.


edit: better yet, could you link to the type of disc you are using? I was under the impression that it was a fiber-reinforced cut off wheel. Now, I think I might be mistaken about that.
 
Have you ever seen one of these disks break?? I HAVE! I was cutting a tang on a cut-off saw and the wheel caught and became shrapnel!

Luckily I was wearing my shop apron and a face sheald. One minute I was cutting a tang and the next I was blasted up against the counter! Pieces of the cut off wheel were imbedded in the wall ceiling and cabinet! The face sheald was ruined, but it did its job!

This was a huge wake up call! I am very cautious around machines! The human body is an amazing thing, but it is damaged easily by equipment designed to cut wood or metal!!

I don't think we are going to talk you out of what you are doing so here is some advice that might be helpful. Place direct pressure on bleeding wounds! Only use a tourniquet IF you can't stop the bleeding! Have a phone handy for calling emergency help...

I will agree that CPM 10V is a high wear resistant steel. I have used it before. I have also done a bit of grinding on HARDENED ZDP-189. I grind RC-61 D-2 on a DAILY basis! I think it is fair to say I know a bit about grinding...... IF you think a belt is a belt is a belt you are WRONG! Sure belt "X" might grind A-2 or ATS-34, or whatever, but you already know that CPM 10V is a high wear resistant steel! If you try and grind it with an aluminium oxide belt you are not going to have success, even in the annealed state!

You need a variable speed 2X72 grinder with 60 grit silica carbide belts! I prefer the 3M Cubitron. I GUARANTEE I could grind that blade on one of these belts! Yes they are expensive, but as has been pointed out... buying cheap belts is FALSE ECONOMY!!

I spend a LOT of money on belts each month! the aluminum oxide belts just don't work well in knifemaking. I know I have tried! They do a fair job on handles, but I have gone to all Ceramic belts with the exception of the 36 grit Blue Zirconia for rough shaping handles, especially natural materials.

I hope you take everyones advice to heart. You asked a question and I think it has been answered.

Tom
 
They make a circular cuttoff saw meant for steel that would do better,and it uses cooling fluid and that would make the blades last longer.

I used one of these saws like you are showing as a cuttoff saw for steel and burnt it up rather quickly.

Making 1/8 inch or smaller cuts down the length of a blade will be a very slow and tedious process and I believe it would be easier to try better belts.But if this is your only way to bevel out a blade,keep a good clamp on the blade and take it slow and easy,and make sure yuor back stop is strong enough to hold the sharpened steel without it digging into it (Brass would be a better choice than wood,or even aluminum)Since you are just making straight cuts into the steel I dont see the danger in the disc blowing up.But if it hangs the edge it can be a disaster.

Just be SAFE !!!!!!!!

Bruce
 
It is Norton Cut-Off blade 10"x3/32"X5/8" for Metal #89390 6110 RPM Max
And Miter saw has 4800 RPM.

I think it has aluminum cover around the disk - not plastic, I tried it with file - it is some metal for sure. And I am not using disk the way it is not intended to be used, I guess It has even less load on it because it is not going deep into metal 2 mm most, no any side load at all.


Tom - What are you saying is that even proper use of cut-of disks is dangerous. And I understand that any metal work is dangerous...

What I get from this - I need this face shield (I use glasses now - like diving mask). Can you recommend some? However again I am not in the same plane as a disk and saw has cover around it.

I have some plex which I will put between my face and the saw as additional precaution.

Thanks, Vassili.
 
nozh 2002,I know what has caused all the guys to get scared here.If you think about it.You are asking a bunch of guys if you can grind with a saw type blade and they all grind on grinders pulling the blade across the wheel not plunge in and back out then in and back out.So they naturally thought you wanted to plunge into a cutoff wheel and pull it sideways across the blade to make the same kind of grind....WOW That would be deadly!!!! but just making a bunch of small straight cuts as you are doing is pretty safe as long as you dont catch the blade edge in the wheel.They are just looking out for your safety,allot of us have been hurt in this business.we just want you safe.

Now if you could make the cut with the edge pointed in the same direction as the direction of the blade turning you would solve have the hanging up problem...I have used these kinds of saws and even radial arm saws with cutoff wheeels to cut patterning grooves in Damascus with great results.Just no side way pulling straight cut only.

Be safe and be glad everybody cares enough to not want to see you hurt.

Bruce
 
Here's what they do in Nepal to put fullers in their kukris:


Clamp the blade down to a 2x4
Fit up a 3 or 4" disc into an angle grinder
Grind the fuller - roughly to shape.


I have done the exact same thing.




I will never do it again.



Ceramic belts work much better...like night and day difference.



Less headache, less pain, less time, less frustration.
 
I would seriously recommend buying a bench grinder they aren't very expensive, far cheaper than a hospital visit. As for problems with your current method, you say that the only way to remove the blade is to slide it off, thats what should worry you, the blade wont be picked up off the magnets but slide off, if somehow something breaks or the disk bites the steel, then the steel piece will slide right off the magnet and bounce off the saw chancing breaking the disk, which will probably destroy the saw seeing as the saw is made for non shattering saw blades the flying disk fragments will just shatter the plastic protective guard and do damage, you will be lucky to be in one piece.
 
Vassili

I have the greatest respect for you, but what you are doing is not safe. In the UK a guy was killed by a disc that shattered an embedded itself in his chest, nicking his heart.

No metal alloy is hard enough that it can't be ground with an abrasive belt. My mentor George Tichbourne grinds Stellite 6K, admittedly it takes one belt to grind one knife, but it contains no carbon and is so hard, it doesn't need hardening a tempering! When you grind it, it looks like a jet on afterburner, just a red fiery glow.

You just need to find a good belt. Try Hermes and tell them what you are grinding. We recently got some green belts (type CR456) in 50 grit and they will cut anything.

http://www.hermesabrasives.com/abrasives/coated.html
 
Vassilli

A question that has not been asked is what type (as in size) of belt grinder/sander you have. If you have a 3x21, like me, you may not be able to get the cubitrons etc. that the experienced makers are recommending.

You will have to find a way to limit how far down your cutting wheel will go. Otherwise, the depth of cut will be uneven and it will be difficult for you to clean up afterwards. If the cutting wheel wears appreciably, you will have to find a way to compensate for it too. You may also want to consider if there is any risk of burning out the carbon when using the cutting wheel, especially near the thin cutting edge.

Good luck.

Phil
 
This is the SCARIEST thread I've

EVER, EVER, EVER, EVER, EVER, EVER, EVER, EVER, EVER

read on any knifemaking/woodworking/machining internet forum. I admit to doing lots of uninformed/brash/hurried things in my life and having been diagnosed with early on-set Alzheimer's disease I've probably forgotten some of them but nothing as SCARY as this. I know what it's like to not have the right tool to do something and to be enormously frustrated because of it. But to put your vision and, perhaps, your life in danger to use CPM 10V is over the top. There are lots of good steels out there that grind easier and will serve just as well for you to practice on.

Please pay attention to what has been said above by people who have no interest in anything except to PROTECT you and save you from PAIN. I can't conceive of enough body protection to make what you're trying safe. Having seen what kickback can do on a tablesaw once with "only' a thin piece of wood, I can't imagine the havoc a 6" x 1 1/2" x 1/4" chunk of tool steel could do.

If you insist on doing this please do it when there are people around to check up on you once in a while.

Syn
 
I am really not seeing the problem here, it's as if chop saws are illegal weapons or something.
 
pso said:
Vassilli

A question that has not been asked is what type (as in size) of belt grinder/sander you have. If you have a 3x21, like me, you may not be able to get the cubitrons etc. that the experienced makers are recommending.
Click to expand...

I have some ceap generic sander -

Sander.jpg

and Grizzli
Grizzly-01.jpg


Professional grinders for over $1000 is too much for my little projects.

pso said:
You will have to find a way to limit how far down your cutting wheel will go. Otherwise, the depth of cut will be uneven and it will be difficult for you to clean up afterwards. If the cutting wheel wears appreciably, you will have to find a way to compensate for it too. You may also want to consider if there is any risk of burning out the carbon when using the cutting wheel, especially near the thin cutting edge.

Good luck.

Phil
Click to expand...

I draw the line 1cm from spine and watching cut not to came over. I also thought about disk wear so I do one cut on one side -one cut on opposite, but so far there is no wear. As I sad it does pick some staff from steel and stop cutting so I have to clean it with file. However this disk is about $5 in H/W store. So I can change few of them.

Now I am not certain about flattening surface, it looks kind of nice. Like Kershaw makes this groove with grooved blade, also Busse came up with some grooved blades. So I may keep it the way it is... Do not decide yet.

Thanks, Vassili.
 
I agree with Bruce Evans in that, as described--plunging in and out, with a suitable wheel, this shouldn't be too hairy, though I'd rather see you using an actual abrasive cut off saw for it. You could set it up, clamp it down and make the cut. That's about as safe as it gets and there may be some advantages if you wanted to do some controlled grooves or something.:thumbup:

A "real" belt grinder with "real" abrasives would still superior for just cutting bevels, though I'm uncomfortable with implication that it's a "safe" or 'appreciably safer' tool/method.

After all, we're working close to unguarded belt edges moving at high speed. (Jim Hrisoulas, for example, suffered severe tendon damage some years ago by brushing such an edge.) Also, belts explode occasionally presenting a potential for severe personal injury. In addition, a belt grinder can throw pointy objects with the best of them and many of the best machines have no guards at all.

How about grinding freehand edge up, as so many do? Roll the edge a bit and "Bang!!" :eek:
Or how about buffing a knife with a soft muslin buff on a bench grinder? :eek: :eek:
I know a number of experienced knifemakers that have been stabbed in the lower parts doing these things.:eek: :eek: :eek:

So take care, whatever you do!:thumbup:
 
That looks a lot like the 4x36 Ryobi grinder I used for the first year or so of knifemaking I did. I probably turned out 30-40 knives (or knife-like objects) on that little grinder with hardware store A/O belts, including ATS-34, 440C, O-1, and even some s30v. My main problems with it were that it lacked power (1/2 hp), belt speed was too fast for detail work, and the motor seemed to get smoking hot if I used it for more than 1/2 hour at a stretch. I've still got it out in the shed in case my 2x72 craps out and I need to get something done.

Be as safe as you can be and take your time. The guys who get hurt are the guys who try to go too fast and either get distracted or start taking shortcuts (never a good idea).

Have a good one and post some pics in the gallery when you're finished,

Nathan
 
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