Homemade Marking Knife

[John Young]

This is a marking knife that I made to try something new and because I had a need for one. I had been using my pocket knife for marking but it didn't feel like the right tool for the task. This double edge marking knife is 5-1/2" long and about 1/2" square. I got a piece of scrap A2 tool steel and milled and filed it to a nice shape. I hardened it to the best of my ability. Then I made the scales from some left over padauk from a chess board project. I used brass screws and nuts and a 2-part epoxy to fasten the scales. I finished the padauk with some tried and true. The last step was to make it scary sharp by flattening the back and putting razor edges on the bevels.

[Mike K Wenzloff]

Well done, John. I really like the shape...looks like it would be a comfortable, positive grip without having to grip tightly.

Take care, Mike

[Howie French]

really nice John, how do you like using it ?

Howie

[jonathan snyder]

Very nice knife John. I really like paduk.

I have been using a very sharp marking knife for dovetails, but just watched Rob Cosman's dovetail video, and he advocates using a dull knife. Rob thinks that layout lines from a somewhat dull knife are easier to see and cut too. I just cant bring myself to dull my knife though!!

Jonathan

[Alex Yeilding]

I've made a very crude one for my use, but someday might want to upgrade to something nicer like this. Some questions if you don't mind:
Where did you get the steel?
How thick is it?
How does A2 compare to O1 when the A2 is not cryogenically treated?

[John Young]

Alex,
I have steel available at work. But you can purchase it from many suppliers. McMaster-Carr and MSC Industrial Supply are a few suppliers. I used 3/16" thick x 1/2" wide piece. At the tip I milled it down to 1/8". If I make another I would use 1/8" thick and mill the tip down a little thinner to reduce the weight. As for the A2 vs. 01, I don't think it will make a difference with a marking knife. As Jonathan posted, a marking knife does not need to be ultra sharp or hold an edge. The lines get pretty small if it is too sharp.

[Ken Werner]

Kudos to you for a fine job. I'm sure you'll enjoy that tool for years to come.
Ken

[Derek Cohen]

Well done John.

It looks strongly made. That's the type of knife that I like to use when scoring dados and shoulder lines. Press down hard, cut deeply, then chisel out against the line.

Regards from Perth

Derek

[Jerry Palmer]

I've made a very crude one for my use, but someday might want to upgrade to something nicer like this. Some questions if you don't mind:
Where did you get the steel?
How thick is it?
How does A2 compare to O1 when the A2 is not cryogenically treated?

A good source of tool steel is old tailed jointer and planer blades.

[Ron Brese]

That's a nice knife John. What was your method for heat treating? With a small area to hardened you probably had a lot of options for doing this.

Ron

[Jonathon Spafford]

That is sure a beautiful little knife... looks comfortable! You did a nice job on it!!!!!

[John Young]

I took a propane tourch to the tip and slowly warmed it up and got it cherry red hot. Then I cooled it fairly slowly. Then it went into the oven for a while at around 350 degrees. I looked up heat treating and found some nice sites. I followed the process as best I could without getting too fancy. I could have heat treated it at work, but I wanted to try the whole process at home.

[Derek Cohen]

I took a propane tourch to the tip and slowly warmed it up and got it cherry red hot. Then I cooled it fairly slowly. Then it went into the oven for a while at around 350 degrees. I looked up heat treating and found some nice sites. I followed the process as best I could without getting too fancy. I could have heat treated it at work, but I wanted to try the whole process at home.

John

My understanding of heat treating steel would indicate that your method is the opposite of what needs to be done. To allow the red hot steel to cool slowly will soften it. Then you cannot temper it in the oven (as it is already soft).

To obtain the ideal hardness, one starts with extra hard steel (quench the red hot steel in water or oil), which you will then temper in the oven. The latter process is to soften it to a specific level, and we use colour to determine (roughly) the level of hardness. So 350 degres for 30-60 minutes (for me it is 30 minutes in a fan-forced oven) will produce a medium straw colour, which is just right for chisels.

Regards from Perth

Derek

[Jerry Palmer]

Actually, A2 steel is hardened by allowing it to cool in the air after taking it between 1700 and 1800 degrees F and keeping it there for a period of time based on the thickness. Tempering should be done immediately after hardening.

Annealing A2 is a slower cooling process in the range of 25 degrees F per hour from a temperature around 1550 degrees F.

[Derek Cohen]

Oops Jerry, I forgot it was A2 ... flashed onto HCS. My mistake.

Regards from Perth

Derek

[Andrew Swartz]

I didn't realize that there is a different process for tempering A2. Does anyone know of a website that outlines the tempering process for different kinds of steels?

[Joe Chritz]

I don't have a website but all the hardening and annealing information on steel is available in some of the machinist handbooks.

When I was making a lot of custom knives (well a lot to me) I looked at doing heattreating myself. It didn't look to be cost effective for knives but for a marking knife it would be easy.

Another option is to gring an old file. Keep it from turning red by quenching often and you are set to go. Many many knives were and still are made from files and old saw blades.

If you are looking for small quantities of steel check local scrap yards, they sometimes have O1 or other common tool steel available.

Also a place like Atlanta Cutlery or Koval Knives would have small quantities as well as handle rivets, pins, tubes and the like. I bought tons of stuff from them several years ago.

Joe

[Jonathon Spafford]

Another option is to gring an old file. Keep it from turning red by quenching often and you are set to go.

It doesn't even have to go red to soften the steel... if it hits blue your gonna have to reharden it.

Andrew, I have some websites on heat treating, but I think they all deal with the traditional steels like 5160 and 1075 etc.

Check this out though... might have something. http://ftpforge.chez-alice.fr/Blacksmithing.pdf

[Jerry Palmer]

Files are way hard for trying to work without annealing if you've got to remove any significant amount of metal or do much in the way of cutting. They are mostly simple HC steel, so fairly straight forward to work with but thicker ones like farriers' rasps can be tough to get and keep hot enough for annealing.

Some time back some block plane blades that didn't pass muster at LN managed to make their way out into the wild in an annealed state. I picked up a couple off of ebay to use for some shop made planes. Used one of them to make a DT plane and had a heck of a time hardening it. It is tough to get them to cool down slow enough to get good hardness. Since a DT plane does not suffer from extended heavy use, I was able to get the A2 hard enough, but don't think I'd want to mess with the stuff a lot with my very limited arsenal of metal working stuff.