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How to sharpen 3/4" mortise chisel

Started by Jan, November 10, 2014, 03:48:46 PM

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Herman Trivilino

Quote from: Ken S on November 13, 2014, 11:31:15 AM
I believe we are worrying too much about squareness.

Those are good points, Ken. The same is true when mortising for a hinge. As long as you're resonably close to square it makes no difference. It's far more important to have the edge sharp and ground to the correct angle.

In my experience the same is true of a plane iron. If it's out of square a bit that can be corrected by an adjustment on the plane itself.
Origin: Big Bang

Herman Trivilino

Quote from: Jan on November 13, 2014, 04:35:34 PM
Something else, I thing, is sharpening an old chisel inherited from your grandfather. Such a tool is usually used only occasionally, but all the more shown as a living history artifact.   

I agree that it's very satisfying to take an old tool that was used and abused and bring it back to its former glory by cleaning it up and putting a razor-sharp edge on it. This is especially true of a tool you remember seeing your father or grandfather use. My father never sharpened his tools or knives properly and I saw him struggle with them. Now I can use those same tools and thanks to my Tormek they work better than they ever have in my lifetime.

QuoteFor this occasions the bevel squarness matters.

And so does the shine! We want to see a mirror finish on those bevels.
Origin: Big Bang

Ken S

Jan,

I see your point about the chisel having belonged to your grandfather. I, too, enjoy using my grandfather's tools. I also have grandchildren. I hope that if they become woodworkers they will keep the tools sharp.  I mostly hope they will use them. The pristine tools we see are the ones which didn't get used.  Honor your grandfather by using his tools to make practical and beautiful wooden objects.

Ken

Jan

Dear Herman, dear Ken I have highly appreciated your comments. It is a very pleasant feeling to know that all over the world there are people sharing the same values. Thanks also for sharing your own personal stories. I have a similar one, but as a non native speaker I am hardly able to tell it as aptly as you. I am really enjoying posting here.
Jan

Ken S

Jan,

I am pleased you enjoy being part of the forum. Our diversity of thoughts and background is one of the things which makes this forum interesting. We share ideas and when we disagree, we disagree civilly. Don't worry because English is not your primary language. We all speak sharpening here.

Do keep posting.

Ken

Jan

As Herman wrote "it's very satisfying to take an old tool that was used and abused and bring it back to its former glory ..."
I am considering replacing the handle of my old heavy duty mortise chisel. The current one has a conical shape with rusty ferrule and rusty metal ring at the top of the handle. The handle is split, the top is smashed. I am not sure about the type of wood. May be it is ash. I have heard that hornbeam is one of the best woods for heavy chisel handles. Hornbeam handle, even without the hoop at the top, should be able to withstand heavy banging with a mallet. I have a peace of hornbeam wood, so I could make the handle on a lathe. Does anybody have good experience with similar chisel rehandling?

Jan

I have decided to keep the bevel of my old heavy duty mortise chisel flat. That is why I have mounted the Universal support on my belt sander, as you can see on the attached picture.


The Universal support is positioned vertically in sleeves drilled into beech wood prisms. It is possible to grind in both directions, but I prefer the direction when the belt is running away from the edge. I use 240 grit belt. The old iron is used to cool the belt sander.

Because my chisel is to big for the Square edge jig (SE 76), I have removed the special Tormek lower clamp and replaced it temporarily with two small steel plates bolt together by four screws.


Because the chisel is twisted, mounting its axis parallel with the belt, resulted in a skewed bevel edge. However, it was not difficult to find an angular deflection from parallel orientation which resulted in more or less square bevel.


Regards Jan


Ken S


Herman Trivilino

Ingenuous, Jan. Both on the USB mount and the modification to the jig.

That chisel looks ancient. Do you have any idea how it got so twisted?
Origin: Big Bang

Jan

Herman and Ken thank you for your response. It is surprising that the chisel twist is not easy visible at the first sight. My understanding is that the chisel is twisted from the very beginning. Below please find an chisel production video showing how a company in this country is still making chisels by traditional techniques.
https://www.youtube.com/watch?feature=player_embedded&v=gittWRq2Sjk
Nevertheless they are  surely many ways how an ancient chisel could acquire some geometrical imperfections.

Ken S

Jan,

You have done a fine job of pushing the Tormek beyond its limits. Do keep up the good work.

I am not surprised that your chisel has a twist. A mortising chisel of that size would have probably been made for housebuilding rather than furniture making. It may well have been hand forged by a local blacksmith rather than manufactured in a factory. Today we expect our tools to look perfect. Years ago how well a tool functioned may have been the primary concern. (We could all learn from that.)

A good source of information about traditional mortise chisels is Christopher Schwarz. He writes a blog and has written many magazine articles and several books. He prefers the traditional design of mortise chisels, such as your grandfather's tool, to the more generally available "sash mortise" chisels. The traditional design is more robustly solid. The oval shaped handle provides more strength to lever out waste and helps keep the chisel aligned. If you do a google search with "Iles mortise chisels" you will find the chisels of that design still being manufactured in England.

If you get on the lie-nielsen.com website, under educational videos (you tube) Chris Schwarz does a pair of you tubes on the technique of draw boring. This is a very traditional method of securing mortise joints. It is very strong, long lasting, and requires no glue. I suspect your grandfather may have used these joints frequently in his work.

I wouldn't replace the handle as long as it still functions. Lie-Nielsen makes some of the world's finest chisels, and they use hornbeam.

I am pleased you have found satisfaction in restoring your grandfather's chisel. Your work honors his memory.

Lem

SharpenADullWitt

https://www.youtube.com/watch?v=8l8T7YOdWpw

I've seen several video's on rehandling (from making them with hand tools, to a lathe, to even a piece of a broken broom handle, like my grandfather would have done), but several did what the above did and it stuck with me.  The copper pipe end piece to keep the handle from splitting.

Compared to some I have seen, your looks useable still.  Clean and fill the crack with epoxy and refinish to get some moisture back into the handle. (another option)
Favorite line, from a post here:
Quote from: Rob on February 24, 2013, 06:11:44 PM
8)

Yeah you know Tormek have reached sharpening nirvana when you get a prosthetic hand as part of the standard package :/)

Jan

Thank you Ken for showing appreciation for my effort. The simple Universal support montage shown above works fine, but it is fair to admit, that the work is not so comfortable and precise as with unique Tormek water-cooled sharpening system.

The belt sander is noisy and dusty. When the belt is worn out and hot it is often bulged in the middle of its width. That is why I prefer the grinding direction when the belt is running away from the edge,  the belt is pressed down before it reaches the bevel edge.

Thank you for reminding the marvelous Chris Schwarz educational videos. I have still to find the one showing the technique of draw boring. It may be interesting for you that Chris Schwarz recommends the Narex mortise chisels (the company shown in the production video). It is because they are probably the  best value for money set available. The Narex steel is softer than Lie-Nielsen (A2 steel, hardened to 60-62 Rockwell) or Ray Iles (D2 steel), but for a big mortise chisels the steel hardness is not so important as for narrow bench chisels.

Jan

Jan

SharpenADullWitt (Randal), thanks for providing link to video showing how a good handle can be done using hand tools only. For my ancient tool this would be more suitable than a turned handle.

I agree with you that the handle of my old chisel is still usable. Ken is of the same opinion. Thus I will postpone the chisel rehandling.

Ken S

Jan,
I remember reading the famed knifemaker, Hoyt Buck, made his handmade knives for US soldiers softer than he could have made them. He knew these knives would have to field sharpened with whatever was available.

I think it is interesting that Lie-Nielsen also makes its chisels with O1 carbon steel. O1 won't hold an edge as long, however, it will take a keener edge and a more acute bevel.

For the rough use a large mortise chisel must endure, hardness or the steel may not be as important as toughness.

Much can be learned from the humble chisel.

Ken