Stamping CPM/High alloyed/stainless steels?

JG Custom Metal Works · May 25, 2018

I’m fed up with the finicky nature of electro-chemical etching and am thinking about getting a stamp.

I know CPM steels aren’t very conducive for forging, so I’m guessing it wouldn’t be optimal to heat it up the blade in a forge to stamp. So how would you go about stamping these steels? With a shop press while the blade is in its annealed state? I have a 1 ton arbor press, would that work? I’ve seen stamping jigs made from arbor presses that hold the blade in position and you hammer the top of the ram. I could probably make something like that pretty easily if I had pics of it.

Do any of you guys use steels like CPM-s35v, CPM-30v, CPM-110, CPM-4v, or CPM-3v and stamp your mark on it.

Where so you stamp your mark? If you stamp it on a nearly completed bevel, do you have to wedge the other side so that the surface that is to be stamped, will be flat? Or are you only able to stamp on a non-beveled, flat area on the blade?

When do you stamp it? In its annealed state? During heat treat? When the blade is hot?

I’d really appreciate any advice you guys could give me. Thanks!

Bill DeShivs · May 25, 2018

Stamp the tang, before heat treat.
I wouldn't try to stamp the bevel.

Randy3000 · May 25, 2018

I too am interested in this. If i may insert an additional question. Since you have to heat the steel way beyond austenizing temp, or else it will cool too much before you can actually stamp it, do you have to normalize? O1 is the steel i am using.

LCKT707 · May 25, 2018

I used to stamp near the ricasso area or the flats above a halfway up flat grind. In it's annealed state and cold. Usually always before I start grinding bevels so I can work my grinds around the stamp. However I've had bending issues in the past and I've had one complete failure (broken 20CV blade) which I fear was from stamping too close to a hole so I now use etching. I'll probably still stamp blanks but it needs to be perfectly flat or you get deformation and that usually means hammering on something not soft and scratching the blank. Hence why I don't stamp an almost finished blade. In the future I'm hoping to have them laser engraved or milled.

Here's a recent stamp on AEB-L

As for like... if that technique is even proper metallurgicaly? I really don't know but I know a lot of makers who use stamps and haven't had issues. A lot of the guys I know use a 20ton press and press their stamp in. I hammer mine in usually with one single hit. Sometimes having to line it back up and give it a second. As for the stamp itself checkout BuckeyeEngraving they do a great job with metal stamps and designing something for you!

JG Custom Metal Works · May 26, 2018

Thanks a bunch for the info everyone, I really appreciate it.

Have any of you tried to stamp the bevel? I would imagine you’d have to wedge the blade so the area stamped would be parallel to the stamp. Correct?

Del Raso Knives · May 26, 2018

I’ve been stamping high alloy stainless for 25 years. Stamping in not just skin deep. It will create a football shaped depression and kick up a bur around the letters. The area needs to be flat and parallel to get an even stamping, a jig to hold your stamp square to the blade is best practice.
Stamping your bevel will most likely ruin your blade, bend it at the very least.

After profiling I finish the side to be stamped to 120 grit. After stamping I check to see if the blade is straight. If not, place the stamped side down onto a piece of flat pine and give the blade a tap with a hammer and check again.

Once it is straight again refinish the stamped side to 120 to get rid of the depression and the peaks around the letters. You can then finish the other side to 120. On stock up to 3/16 you will notice a football shaped hump become visible as you grind away the scale.

At this stage I take both sides to my desired final finish an inch or so above and below my stamp. Next step is to make and fit any guards, grind and finish the bevels, taper the tang, and last heat treat.

Stamping will force you to design knives with a flat big enough to accomodate your stamp. Keep your stamp small and as simple as possible for this reason. The more complicated your stamp the more force you will need to use and the more distortion you will create.

Hope the above procedure is of some help. Peter.

E.Carlson · May 26, 2018

I use a 6 ton Harbor Freight A frame and it works great. Even on 15N20 which comes from the mill at around 45rc. As long as your steel in its annealed state is softer than that, you shouldn't have an issue.
On full flat grinds, if you want to stamp on the blade, I leave a small flat area at the spine that is easily blended while hand sanding. Keep in mind I have a small simple stamp.

john april · May 26, 2018

i stamped cpm 154 while red hot before heat treat, it worked with no bad effects. after heat treat the blade was a brownish rust color ( peter's heat treat) and so was my stamp. so i took an etcher and put it on "mark" to blacken it. but it still got worn off by the buffing wheel and i ended up with a silver /gray mark. looks fine though. i always stamp on a flat spot.