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