Touchmark/Maker's Mark tips/help

[Mrhappybottms]

Hello all,

As some of you may know, I am a college student. For one of my class projects I have to design and make something using the school's CNC Mill, and I spoke with the teacher and he said that I could make a metal stamp. I wanted to make a touchmark to stamp on my future blades, and I'll be buying some round stock of O1 tool steel to use. My main question is how deep should I cut into the steel for the stamp? The design is a pretty basic 10 toothed gear with a hole in the center, and will measure around 0.25-0.35 inches in diameter (I'm still working on the CAD Model to make it look the best, and to make it doable with the engraving bits we have, so the exact size isn't finalized). I'm also thinking of getting another smaller piece of O1 tool steel and make the same design but smaller by hand, but I probably won't do that for a while. So long post short, how deep should I engrave the touchmark so I can stamp a blade and have it not be removed when I sand/polish it?

[Glenn]

Touchmark designs can be of two types, into the metal, or standing proud of the metal. Standing proud is more difficult as you are driving a lot of metal down in order to raise the make. Into the metal is easier because you are not moving a lot of metal, just enough to sink the design into the metal.

Either way, you are moving metal and the design must take this movement into consideration.

The overall mark size should be designed around the project. As with any design, it should be easy to see, and easy to read. The mark on a knife blade would be different from the mark on a 2 inch square upright on a gate. No one said you could have only one stamp, so when you get your design, make several (spares) in a couple of different sizes. 

[Mrhappybottms]

Thank you Glenn, that is some good advice. I was planning on trying to have more made, but for now I'm going to try to get at least one size for my class project. I'm going to try making the stamp so it stamps into the metal, as it will probably be easier. I also plan on adding a chamber to the edge to help move material when I stamp. Right now, the size is limited by the size of the engraving bit that will be available to me. I'm going to try making one as small as possible(given the size of the bit). But I do plan on trying to make a smaller one. I plan to use both primarily on knifes and larger work, since my smaller stuff is typically made from 1/8th inch rod, and I'd need a tiny stamp for that. Anyways, thanks for the advice, its always nice to hear from you, Glenn!

[Glenn]

You can use1 inch round stock with a very small stamp at the center of the face. Making a stamp from 1/8 inch rod can be a challenge due to the size of the original stock. To speed up the project and understand how things work, make a prototype and press it into modeling clay.

Keep in mind that the leading edge of the stamp is (usually) contacting HOT metal. It should last through many hundreds of impressions, not wear, and not loose its tempering.

 

You may want to review The cow pie analogy of hammer dressing by Shane Stegmeier.

[Mrhappybottms]

Yeah, i was looking at 1" O1 steel. I was also thinking of using a lathe to put an angle on the rod so it tapers down to the size of the actual stamp face. I'm just trying to figure out how deep to engrave the stamp. I'm thinking around 0.1mm, but I haven't been able to find anything about how deep to make the stamp itself. and the 1/8" rod i mentioned wasn't for the stamp, I was referring to some of the metal I use to make things(such as pedants). I realized after I posted that it may not be clear, by bad

[Glenn]

The parent stock for the stamp should be comfortable to hold and should have a way to index the stamp to the correct position.

[aessinus]

I duplicated my branding iron from high school welding into a couple of touchmarks from old allen wrenches.  Straightened/annealed in kitty litter for the mill/file work then re-hardened.  Work a treat.  The small one (1/4" hex) I cut with an .06 ball-end and filed the last details with needle files.  The 1/2" I used a 1/8 BE mill to dykem lines .  No CNC, just cut to a line & filed.  Test-driven in alum plate to verify the finished mark.  A few trys to get the edge geometry; finally settled on an 80-90 degree on the business edge & they've held up for a few hundred uses.   As Glenn mentioned, a bottom index keeps you from fumbling.  A grind across the held end for bottom naturally lines up in your thumb pad.

[ThomasPowers]

Less than 1/8"----generally 1/16" heavy will be fine and you won't drive it all the way in anyway if you make it deeper.  

[SLAG]

Mr. Hppybtm,

Glenn's idea of making a preliminary punch and then impressing it into clay in order to work out depth shape and size is a good one.

I have a suggestion to speed up the process. Test the concept by using a hard, tight grain wood. It is easier to carve than engraving steel and it's quicker to test and modify.

An ideal wood for the purpose is boxwood. It was the traditional wood used by craftsmen for woodcuts. Hard maple will work just as well or some other fine grain hard wood.

You can then use fine files (for example, needle files, or small riffle files, or a rotary tool to cut into the wood). to carve the design.

Just a thought,

SLAG.

[ThomasPowers]

Note that for boxwood you can probably find "pen turning blanks" at a reasonable size/price.

[Kozzy]

Since you would be machining with tiny endmills, everything changes a little--you might want to try the prototype in machinable wax to work out the details of the impression and see what the tooling actually leaves you with.  Machinable wax should be hard enough to use as a preliminary clay punch to give you an idea of the results also.

Then you get to play with the wonderful world of feeds and speeds with micro-milling on hard metals.  It's amazing to see how tiny feed/speed tweaks make the difference between an endmill failing quickly and lasting a remarkably long time.