# Sharpening chisels with an angle grinder



## newbiewoodworker (Aug 29, 2010)

I was wondering what works better for sharpening chisels with an angle grinder… A flap disk, or a grinding wheel? I asked my shop teacher if it was safe to do with with an angle grinder, and he said yea.. so I am not so concerned with safety… because I Plan to hold on for dear life and that was reassuring…

But what is better? I watched the service tech use a flap disk the other day to put a bevel on that pin that holds the bandsaw motor in place… it seemed to do it fairly quickly… but is this better than a grinding disk/wheel?

There is also a large price difference… 10 grinding wheels is $8 at HF… at homedepot, flap disks are $5.30 a disk… they are $5 at HF… but I would make up that 30c in gas…


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## DavidFisher (Apr 11, 2008)

I wouldn't be inclined to use an angle grinder for this type of application. They have a way of grabbing things and tossing them unless they are securely fastened.


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## alba (Jul 31, 2010)

Just get a cheap oil stone.
Then your sharpening is free, SAFE and your not going to …..
your chisels.
Jamie


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## newbiewoodworker (Aug 29, 2010)

Im not worried about tossing things… believe me… if I had to, Ill mount the darned thing to the table…


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## newbiewoodworker (Aug 29, 2010)

Besides… they are cheap… if one goes through the wall into the laundry room… it only cost me a buck or so…


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## Sawdust4Blood (Feb 16, 2010)

I would forget the angle grinder. Sharpen them by hand with a stone or diamond plate. It's an important skill to learn, will give you a better edge, and it's safer for both you and the chisel. I sharpen my chisels with waterstones (up to a 5000 grit Japanese stone). If you keep them up, it doesn't take much time to renew an edge and mine are sharp enough to shave with. The key to making an edge sharp is consistency in the angle you grind. Maintaining consistency for a really great edge is nigh on impossible if you're trying to hold an angle grinder to a chisel by hand.


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## ropedog (Mar 26, 2008)

This is not an ax, you do NOT sharpen a chisel on an angle grinder,first it is not safe, second how will you be able to hold a bevel, third the angle grinder is going to heat up the steel of the chisels which is bad for them. Just buy a set of stones and learn how to put a nice edge on by hand.


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## Benighted (Jul 26, 2010)

The hardened metal in chisels and other cutting tools loose the correct hardening and molecular structure when heated (and in carbon steel, the carbon becomes "denatured", which is a irreversible reaction), so it's a bad idea for your tools (and possibly your health) to use a angle grinder on them.


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## richgreer (Dec 25, 2009)

I'll join the chorus. Sharpening with an angle grinder - - not a good idea.


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## newbiewoodworker (Aug 29, 2010)

I did it… Unfortunately I was out for a class extra credit assignment, when you guys wrote these… All I can say… Is I am glad they were cheapos…

I also learned that when something feels hot in the hand that has a leather glove on it… its not a good idea to pick it up with the hand that has a light weight nylon glove on it… the bandage on my finger is now fused to it…..

I am just now sharpening them up to use as real beaters… such as prybar and screw driver uses…
Not to mention they will work well for learning to sharpen them…

The remainder of my method is the Scary Sharp™ method… 4 grits of sandpaper: 200, 400, 600, 1000, glued to a piece of plexi… HD didnt carry plate glass.. plus it was only $4 for a piece a little bigger than a sheet of printer paper… and about 1/16-3/32 thick…

As for the safety… its remarkably safe, using a flap wheel. I was worried about a AO disk fragmenting, so that influenced the decision… And because the guard is bent(I dropped the grinder… opps) I had to take it off to use a screw on… even more reason…

But what I hate… is when ever I grind, I end up blowing black snot for the rest of the week… and having that metallic taste occasionally…

Sawdust: I dont hold the grinder… I put the grinder on my planer table(I covered everything with plastic, since I didnt want metal in my machine.. or in the wood…) I then stablize it with one hand, while holding the chisel in the other…


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## swirt (Apr 6, 2010)

Hardened steel for a prybar??? an accident waiting to happen.

Sharpening on 1/16" plexiglass?.... too flexible to stay flat unless you put it on top of something solid like a table saw.

A loose angle grinder held on top of a planer tabler???

I get the feeling you are pulling our legs to be funny.


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## newbiewoodworker (Aug 29, 2010)

Well then, your feelings are incorrect. That is how I did it. And it works fine. I do put the plexi ontop of my workbench, I just used it as something to hold down the paper/ minimize bumps…

Yea.. the pry bar idea was just a joke… I know thats not exactly a good idea.. lol


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## Howie (May 25, 2010)

I'd find another shop teacher.


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## hairy (Sep 23, 2008)

I use one of these: 
http://www.leevalley.com/US/wood/page.aspx?p=60311&cat=1,43072,43078&ap=1

I use it on a coarse oil stone to set the angle, then a fine water stone to sharpen. The first time takes a while, after that it's easy. You will need to make a jig to set the proper angle, but that's easy. I'll post a pic if needed.


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## Howie (May 25, 2010)

After rereading this..".not so concerned with safety" You should always be concerned with safety. If something happens and that grinder gets loose you are seriously injured before you know it. Your shop teacher should have pounded this into peoples heads. Safety first is not a joke. You might get by sometimes but it usually catches up with you.


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## newbiewoodworker (Aug 29, 2010)

You mis-interpreted what I meant… I still have a hand on the grinder.. its just resting on the table.. but with a firm enough grip.. I also grind on the side thats coming toward me, not away..

Believe me… I let myself get careless, resulting in one of my leather gloves(old winter ones) getting a nice hole burned right through 90% of the layers…


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## PurpLev (May 30, 2008)

"I also grind on the side coming toward me, not away…" - so you are holding an angle grinder with 1 hand, and hold your chisel with just 1 hand plus you're grinding it towards you?

there is not even a single positive thing that I can think of in that technique - it's unsafe in more than 1 way, it's imprecise and will not get you a good bevel on the chisel. if you want to practice sharpening -do it right.

FYI. if you really do want to use an angle grinder to make the bevel - you need to clamp the grinder to a workbench so that you can guide the chisel with 2 hands - AND using some sort of jig/guide for the chisel to keep it steady.

put that aside - you also mentioned that you felt the chisel HOT while wearing a LEATHER GLOVE? this chisel can go to the trash - it has lost it's hardness.

rule of thumb (no pun intended) - if you can't hold the chisel with bare hands - it's TOO HOT. once hardened tool steel gets overheated, it looses it's hardness and at that point - useless as it's too soft.


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## newbiewoodworker (Aug 29, 2010)

So glowing red hot was bad?

You also misread: I grind so that its on the side of the disk thats coming toward me: But the chisel is pointed away from me.

Like I said: I am just using them for basic things, they were cheap junkers.. It wasnt so much as hot in the leather glove… as in the Nylon gloved hand(leather palm)... Next time I go to HF, I am going to get another set that I will keep scary sharp, for use on delicate tasks… So this one is the junker set..

I actually got one of them pretty darn sharp… and I re-beveled the small one for a 10o-15o bevel… so that its better for carving… that one is sharp…


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## newbiewoodworker (Aug 29, 2010)

I might try to re-temper them… I have heard of ways of doing it… What temp does PVC melt? I want to try to do this without melting the handles….lol..


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