Corner chisel

[Seth Poorman]

Hi fellow Creekers
I just got this James Swan 1/2" corner chisel at auction and I thought maybe one you had a special and easy way to sharpen it. It looks to me to be a no brainer : {Position it horizontally in wood vise and lightly work my ceramic stone parallel with the inside bevel} Am I correct in my thinking? Or is there another Magic way of doing it?
Thanks in advance Seth...

[Bill Keehn]

From the Robert Sorby website:

Sharpening a corner chisel is by no means easy even for the expert. There are two alternative methods which may be used.


The first – and probably the easier – is to place the chisel in a vice and hone each of the inside cutting faces separately with a diamond hone or file. This method gives you a clear sight of exactly what is being honed.


The second method involves and oil or waterstone. These should be flat and have a sharp edge. Again the inside cutting faces should be treated separately. The first cutting face should be worked against the stone with a side angle to ensure that the whole face is sharpened. The second face should be sharpened in the same manner but using the opposite edge of the stone.

[Seth Poorman]

Thanks Bill
I think im going to try 2nd method for starters.. I have a slip stone that has a sharp point that i think would finish the inside corner nicely.

[Alan DuBoff]

Seth,

I have seen this said also, but I find that a corner chisel is like any other edge tool, and having a proper way to sharpen it to be as valuable.

Flatten the outside flats on a stone of choice, water or oil.

If the bevel is really bad, start with a grinder and/or file. I have used a hand grinder with some success, but the problem is getting into the corner to get it sharp also. Carefully use a saw file to clean the corner out. In general you would be amazed at how much a small saw file can do for sharpening an edge.

Small slip stones work well for the bevel side also, and one technique I have had success with is the same I use with drawknives, scary sharp on a stick. Wrap some sand paper on a small stick and stroke into the edge, finally stropping away from the edge.

Be very careful as you sharpen into the edge, this violates most rules of safety, so practice at own risk...;)

Small diamond stone also works well, Woodcraft sells some small ones for about $10-$15 that fold out, this is helpful after the file, in my experience.

Also small slip stones as machinists use on their lathe tooling work well also, I have tried all of these with the one corner chisel I have.

With all that said, I found mine at a flea on the cheap, so have it in my arsenal, but it is nothing that you can't do with a regular chisel and 2 separate cuts. That is actually a more useful skill to have, chopping clean corners with a regular chisel. :) However, it is much easier to do with a clean/sharp corner chisel, and if you have it, take the time to properly sharpen it, you probably won't be using it too much but when you do it will be ready to use.

FWIW, I find it good to stroke the saw file into the edge and moving away from the corner, so cutting in/away at the same time.

DISCLAIMER: I only have a single corner chisel and have only used it 3 or 4 times. It has been handy, but is tricky to sharpen as most say, but it's not rocket science...

[Seth Poorman]

Alan
Thats all good advice, I do have a small diamond stone like you mentioned but I do not have the saw file, Im not even sure that I know what they look like as I have never needed one until now,so I will check on them.

[Jim Koepke]

A saw file is a three corner file. Good to have in all the sizes to fit your saws if you sharpen your own.

An auger file or safety file is one that has teeth only on two of the four sides. This is so you can get right up to an edge without cutting into the edge. That would have been my guess on what to use with a corner chisel, but since no corner chisels are in my possession, it is not something I know about.

jim

[Seth Poorman]

Thanks for enlighting me Jim, I do know about the 3 corner files ,I just didnt know they were saw files.....:o I have a hand saw and I think Ive used it 2-3 times in 15 yrs...Its still vary sharp...:o

[Alan DuBoff]

Thanks for enlighting me Jim, I do know about the 3 corner files ,I just didnt know they were saw files.....:o I have a hand saw and I think Ive used it 2-3 times in 15 yrs...Its still vary sharp...:o
You outta try using your saw more often, they are actually quite a bit more useful than a corner chisel. :rolleyes:

You can buy triangular saw files at most all popular hardware stores. Ace & OSH & the BORG all have them. If you have a saw, get one the same size you need to sharpen it, and your just in time for BobR's Saw Sharpening - Suggested New Skill for 2009 (http://logancabinetshoppe.weebly.com/1/post/2009/01/saw-sharpeningsuggested-new-skill-for-2009.html).

If you ask me, it's your lucky day! ;)

EDIT: Seth, curious what type of saw you have that you acquired 15 years ago? Modern handsaws between the 60s and 90s were garbage available in America. Maybe there's a reason you haven't used your saw but a few times in 15 years...

[Seth Poorman]

You outta try using your saw more often, they are actually quite a bit more useful than a corner chisel. :rolleyes:

You can buy triangular saw files at most all popular hardware stores. Ace & OSH & the BORG all have them. If you have a saw, get one the same size you need to sharpen it, and your just in time for BobR's Saw Sharpening - Suggested New Skill for 2009 (http://logancabinetshoppe.weebly.com/1/post/2009/01/saw-sharpeningsuggested-new-skill-for-2009.html).

If you ask me, it's your lucky day! ;)

LOL......:) What do ya know Alan , I killed two Birds in one thread...
Now I will be able to sharpen both. Ill stop at Ace on my way to work
Monday.

[Doug Shepard]

I finally bought one a couple years ago and used it a few times so far. It came pretty sharp already so I haven't tried to to anything with it other than lap the outside a bit. I wondered what I'd do if I ever had to regrind in case of chipped edges and thought about my belt/disk combo sander. Maybe rig up a jig to hold the angle then hang it off the edge of the belt platen to get inside up to the corner?? Would that work?

[harry strasil]

Find a piece of close grained hardwood, 3/8 thick by an inch wide and 8 to 10 inches long. Glue 4 different grit strips of wet/dry paper 4 inches long to the wide sides of the hardwood strip, using both ends and you have a nice wet/dry 4 grit hone, using another hardwood strip, glue 2 strips of leather to two faces, one rough side out for getting rid of the burr and the other smooth side out, use jewelers rouge on the smooth surface to polish the very tip, you now have a strop for corner chisels. use a belt sander or sanding disc to touch up the edges to get into the corner well with square edges. FWIW

[Bill Keehn]

I like Harry's idea. You could tweak the edge of the hardwood block to perfectly fit the corner of the chisel bevel.

[Alan DuBoff]

I like Harry's idea. You could tweak the edge of the hardwood block to perfectly fit the corner of the chisel bevel.
I don't think you can.

Do you own or have you sharpened a corner chisel before?

My corner chisel has an arched corner where the two sides come together, and I don't see how you would easily shape a piece of wood for it which would be able to easily attach abrasive to.

If you have done this, I'd sure like to hear how you did it, maybe it's something I should try. OTOH, maybe I don't understand what Harry is exactly saying, but scary sharp on a stick is about as close as I could get myself.

[Bill Keehn]

Alan, yes and no. Although I've been thinking about getting a good one, right now all I have is one of those spring loaded corner chisels for squaring up hinge mortices. Until now I haven't sharpened it, although it needs it. Each edge of that chisel has a double bevel. The bevels are ground flat so there is no arch where the bevels meet (at about a 100 degree angle). I don't see an arch in Seth's picture either.

Are you saying your bevels are not flat? If not, then I don't understand and I don't know what you could do to sharpen it.

I was saying that I like Harry's idea of using a wood block and gluing sandpaper and leather to it. I'm just suggesting doing both sides at the same time on a block that has a 100 degree edge (more or less).

[Alan DuBoff]

Are you saying your bevels are not flat? If not, then I don't understand and I don't know what you could do to sharpen it.
Yes, that is exactly what I mean and how I sharpened it as exactly as I described above. The triangular file works wonders, IMO, and can do most of the heavy shaping so that a diamond or scary sharp on a stick will finish it. What Harry describes is basically scary sharp on a stick, I was just pointing out that if you spent the time to get a piece of wood to fit into the v nicely, you could have sharpened it and be chopping corners in the same time, IMO. I use the corner of a stick to do the same thing, it just doesn't fit perfectly.

This pic is not great, but the best I can get. The flash keeps creating bright spots.

FWIW, you should try sharpening your corner chisel how you suggested Seth do his, so you would know better how the process works. It's easy to be an armchair woodworker, all too easy, IMO. ;)

[Bill Keehn]

FWIW, you should try sharpening your corner chisel how you suggested Seth do his, so you would know better how the process works. It's easy to be an armchair woodworker, all too easy, IMO. ;)

Too true. I didn't do it before because I didn't know how and I'll have to take it apart. The thread caught my attention since I'd been wondering, so I decided to look it up. I'll get around to it sooner or later, but for now a regular chisel works.

[Alan DuBoff]

Too true. I didn't do it before because I didn't know how and I'll have to take it apart. The thread caught my attention since I'd been wondering, so I decided to look it up. I'll get around to it sooner or later, but for now a regular chisel works.
One thing I did think of that I did on mine with pretty good success just now was to wrap the triangle file in paper, it works well to get into the corner using the edge of the file.

When I first got my chisel the edge was completely flat on the front, as if it had never been sharpened. It's a giant foundry type chisel. The rounded section in the v was much more accentuated, I used the triangular file to clean it out some, but it is still an odd shape to try and contour.

I agree with you completely on the last part, a regular chisel works just fine. Mine can only be used on large mortises for the most part, it's too big for most furniture and/or cabinet type work. Mine is 13/16" so it is just a tad big for most 4/4. Works well on anything bigger.

[harry strasil]

A Corner Chisel is basically a Timberframing tool used to remove the leavings of the initial boring of the mortise. If you have used corner chisels much, you will note that they have a tendency to draw themselves back towards the "V" of the corner and if you are not watchful you will end up with a mortise that is bigger down deep that it is at the top, making for a very sloppy fit.

[Alan DuBoff]

A Corner Chisel is basically a Timberframing tool used to remove the leavings of the initial boring of the mortise. If you have used corner chisels much, you will note that they have a tendency to draw themselves back towards the "V" of the corner and if you are not watchful you will end up with a mortise that is bigger down deep that it is at the top, making for a very sloppy fit.
This is also true of a bench chisel, also. Wouldn't you say that most people have a tendency to over cut the bottom of the mortise? IOW, make the bottom wider than the top...I know I have a tendency to do that myself.:o

That is exactly how I've used mine Harry, as you describe, after I bored out as much as I could with a brace.

That said, I have used a mortise chisel with great success on my workbench, pictured here.

[harry strasil]

FWIW, on my large timber framing corner chisels, I have sharpened the two sides at a skew angle, as this has a tendency to cut much easier and not tear the grain in soft woods, then I clean up the bottom with a regular firmer chisel. Also on large mortises up to 2 inch, I often just use a 2 inch firmer like a mortise chisel to cut the mortices.