Re-honing chisels badly dinged by misuse

zeke · Heavy Crude Joined: Dec 07, 2007 Posts: 185

I'm not sure how, but I believe that teenagers and stones were involved...but the chisels we have (Craftsman, set of 3) are badly dinged along their cutting edges..

I don't believe the damage is irreparable, but these are serious dings; more than just a burr here and there.

A buddy suggested I take them to a hardware store where they could "buzz off those nicks in a jiffy," but I'd like the opportunity to learn how to do this myself.

My only question is, could I do more harm than good to these edges simply by making a rookie mistake?

I have a decent stone, which is intended to use with kitchen knives; one side coarse, the other side fine.

I also have a set of files, and I envision using the files to remove the burrs and restore the edge shape, then moving onto the stones to restore the actual cutting properties OF the edges.

Am I way off, or should I dive right in with this plan? Am I in danger of ruining the temper of the steel as I'm using elbow grease-powered methods?

thanks!

zeke
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darwinsdog · Heavy Crude Joined: Jun 27, 2008 Posts: 170

An electric grinding wheel will heat the metal & case harden it, making it brittle. Files & hones are the way to go but will take longer. A hand cranked wheel is what I'd use.

MD

green_achers

Assume you mean a wood chisel. Should sharpen OK with a grinding wheel, but you'll need to squirt a continual thin coat of oil as you grind, and take your time. Can't say I've done this, but I've seen it done.
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zeke · Heavy Crude Joined: Dec 07, 2007 Posts: 185

Yes, they are wood chisels.

I do not have a grinding wheel...only elbow grease, some files and a stone.

I thought it would be a good experience to learn how to do it this way, even if not ideal by the methods available now.

zeke
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MD

MD

zeke · Heavy Crude Joined: Dec 07, 2007 Posts: 185

SpringCreekFarm · Intermediate Crude Joined: Mar 03, 2006 Posts: 925

I can hop in here with some advice.

First of all forget using the hand stones until you are ready to hone. You first need to get the nicks out straight away. Get yourself an aluminum oxide wheel with a soft bond and an open structure as these grinding wheels don't get the metal as hot. If not then follow the advice given above and go slow with lots of coolant. I wouldn't use oil on a grinding wheel myself but maybe others have success with that.

Hold the chisel perpendicular to the wheel and get those nicks out and give yourself a nice square edge to work with. You'll end up with a big flat surface on the end of the chisel but the nicks will be gone.

Next thing to do is to grind the angled edge. Go slow and get your edge back to a rough finish. DO NOT ever grind the flat side as it needs to be completely flat with your angle meeting that plane from the other side. Only grind the angled side. Using a wheel will give you a hollow ground angle because of the curvature of the wheel. This is ok because the final edge is created when you hone.

Belt sanders with an adjustable rest are also handy for quickly removing material to reestablish the angle on the chisel. These give you a flat surface on which to hone.

A chisel isn't a chisel, to me at least, until it has been honed. The best chisel is one you don't need to hit with a mallet but one that slides through the work because it is razor sharp. Depending on how serious you are about your tools, it will pay dividends in time to get a chisel sharpening jig and a good set of stones. I use a stone that has a 600 grit for rough honing and a combination stone that has a 1000 grit on one side and a 4000 grit on the other side. I don't go for the mirror polish but that can be achieved and literally a razor edge if you get into the buffing compounds and strops.

Although it sounds like I'm a serious woodworker, I'm not. I'm a farmer type guy that got sick and tired of using dull tools and a dull mind to try and fix them. I did some research and found the quickest, cheapest way to keeping my planes, chisels and other things sharp and reliable for when I need them. That is what I've outlined above. I hope this helps.

MD

green_achers

SCF, do you use a special type of belt for the sander? I've been wondering the best way to keep cultivator sweeps sharp. Could get tedious with a file.

Not to hijack the thread or anything...

zeke, I don't have a vise mounted yet, but I get a lot of use out of C-clamps. You could clamp the file flat to the bench and hold the chisel in your hand.
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kpeavey · Expert Joined: Oct 04, 2004 Posts: 1313

These folks are offering good sound advice.

Bringing the thing back to life with the dings you describe will take some time. A belt sander can speed things up roughing out the worst of it. Ask around, perhaps you know someone who has a bench grinder or even a belt sander. This could save you a lot of time and effort.
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MD

One more tip:

You could take a medium grit cloth based sand paper (wet use) and duct tape sheets of it to a bench top.

work the blade against the paper in smooth strokes, just like you are planing wood.

Then finish with fine paper, then hone.

This may be the easiest method to facilitate holding the proper angle, but could take considerable time if the dings are deep.
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patience · Expert Joined: Jan 04, 2008 Posts: 1664

All the advice above is good. I own a machine shop and make and sharpen all kinds of things, and have often thought that if for some reason I no longer had a big shop, what is the most important machine to get?

Answer: An electric bench grinder, no question about it, and a hefty one. Say about, 1 hp, and 3/4" thick x 8" diameter stones. With that and a good collection of hand tools, I can make a LOT of stuff and keep it all sharp. Worth the money.

I'd put a serious wire brush wheel on one end, and save the stone that came on that end for later. No end of uses for a wire wheel to clean up stuff, and deburr things.
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WisJim

Cheapest solution:
Buy some silicone carbide wet-or-dry paper (commonly referred to as "wet or dry sandpaper). Get a sheet each of 60, 80, 100, 120, 320, 400, 600, 1200 grit paper. Get a scrap piece of 3/8 inch to 1/2 inch think plate glass, a foot square or bigger, unless you have a table saw. Tape half a sheet of the coarsest paper to the glass (or to the table of the table saw) so it is flat. This is your substitute extra coarse sharpening stone. Use it to take the nicks out of the files. Then do the same with the next finer sheet of abrasive paper, and the next, going through all the grits in sequence until you have a nicely polished edge on the chisels. You can go to finer grits, but you may have to get the finest papers at a shop that sells supplies to body shops (that work on auto body repairs).

Google "scary sharp" for better explanations. I use this method, but usually start with a bit of time on the grinding wheel if something has big nicks. I use WD40 or kerosene sometimes as a lubricant--it helps the paper last longer. Each sheet of sandpaper can be used over and over again if it doesn't get clogged with metal bits, so that is why you use a lubricant. Some people use contact cement in a spray can to glue down the sandpaper strips, with them lined up side by side on a piece of plate glass. Scary sharp