Help please.

[Arnaud Van Tilburgh]

Jeff, indeed about vibrations, There is nothing wrong with the thermolock, But in my experience a wooden block with setters cement works best, and make sure the whole object is "melted" in the cement. I learned that if it is not, I can't even control the dept of the cuts properly, as the way the object cuts changes.
So top important to eliminate the vibration.
I once tried just to use the GRS pins for the vise to hold a plate, only when the plate is tick enough this works, but best is making a hard wooden block with "setters cement"

arnaud

[Kevin P.]

Arnaud, when you refer to 'setter's cement' is that shellac you're talking about?
Kevin P.

[Daniel Houwer]

Hi Jeff, did you try Lindsay's M42 gravers? They worked a charm for me with a 50degree face on it. (sharpened with a 19mm spacer with the lindsay templates) Don't know what stainless this is, but it was quite unpleasant to engrave.

[Ray Cover]

I'll toss my 2 cents in here.

I hate carbalt, carbide, and other carbide based materials for some things and love them for others. You have to consider the properties of the graver material to apply it to its best use.

Some thoughts on carbide based materials like Carbalt and I assume C-max. I have not tried the C-Max yet but from what I have read about it it seems very similar to the Carbalt.

When these type materials are used in industrial applications as a cutting material the cutters are almost always ground with a radius at the cutting point (or dubbed). Cutters of these materials rarely have a angle on the point less than 60 degrees. They are almost always made with a substantial amount of material around the cutting edge for structural support. As a matter of fact, most cutters made of those materials today are made in the form of inserts in some configuration of an equilateral triangle so the cutter can be turned to a new sharp edge when it breaks.

These materials are very hard and good for machining hard materials with the right coolants and machine speeds.

The downside to these materials is that they are brittle and they need a substantial amount of material around the point to make it strong enough to hold up.

Here is how that applies to gravers.

I make MOST of my gravers tiny. The face of my 90 degree square gravers range from .015" to .025" and my heels on these may be less than .010" long if I am planning to do detailed shading with it. On top of that I put a long taper on the sides and top at about 5 degrees. This makes for a very small pointy graver that is nice for making accurate cuts. However, that type of point geometry does not have enough structural support at the point to properly utilize a carbide based material. It is just too small and thin for those brittle materials to not break.

I have tried it and I can't get two small cuts out until I have broken the point and need to resharpen.

On the other hand that same graver made of cobalt or HSS will last quite a while between sharpening. The material is not as brittle and does not require as much structural support at the point. For general cutting and detail gravers I almost always use either cobalt or HSS blanks.

Don't think I am dumping on the carbide based materials because they do have an important place on my bench.

I find that this type material is awesome for large beefy gravers. I use these materials in my flats for background removal and rounds that I use for flare cutting along with other such gravers.

I have cut several projects with those rounds and have not resharpened them since I made them. these rounds have a radius on the face with a 45 degree face and a 15 degree heel. The large flats have a 55 degree face and a 30 degree heel (as long as they do not get too narrow they hold up for a long time).

To get the best out of those materials you need to:
-use them with a geometry that gives a LOT of structural support on the point.
- dub or radius the point to make it stronger
- a good polish on the point makes it stronger with these materials.
-if you get them hot when grinding DO NOT quench them in water.
These materials are air hardening. quenching them when hot can damage the material.

Polishing is important with these materials. A scratch (grinding lines) provide a place for a break to start. That is the way the common glass cutter works. You score a line along the glass. When you tap it, it breaks along the scored line. IF you polish away the grind lines from your lap you are not providing a place for a fracture to start.

Ray

[Christopher Malouf]

I'll toss my 2 cents in here.


the cutters are almost always ground with a radius at the cutting point (or dubbed).

Ray

That right there is the key Ray. I always dub the tip of a Carbalt graver when engraving 300/400 series stainless and 4140/4150 steel. Usually just dragging the tip across a porcelain wheel a couple of times is enough.

[Idaho Flint]

Jeff

I had a similar experience with a Gerber knife I was engraving for a friend that was harder than anything I have every touched. I tried Glensteal (my favorite metal) and it would dual in seconds. I then tried carbine and it would break in about 1mm of cutting. I was using a 90 degree with 55 degree face. I decided that I had to try the C-Max. I purchased one and gave it a try. It worked great. I was able to go further than ever before in this steal. Its tip would still break in time, but I was able to do a lot more before that happened. The only downside that I had with it is that when the tip would break it would be a much larger chunk of metal than the other gravers. It would take a lot more sharpening to get it back and the tool was dwindling a lot faster than other gravers I have worked with in the past.

There is a lot of truth about different strokes for different folks, but I would recommend getting one and give it a try for yourself. I am glad that I did.

Mike

[jetta77]

Thanks again everone for posting, alot of good information came out of this thread, very informative to say the least.

Daniel, those rings look great my friend.

[sam]

You're getting a lot of quality advice here, Jeff. Putting a radius along the keel line of the heel can strengthen it substantially. If it's slight you won't notice it when looking at the cut. For shading I keep the keel line sharp so my shade cuts will have that nice taper at the start of the cut. An option to a radius is simply swiping the very point of the graver across the ceramic lap to strengthen in. The very point is the weakest part so taking off that point can work wonders.

I'm probably repeating some of what's already been said...forgive me.

[Kevin P.]

This thread is an example of what's best on this forum. Lots of informed input on how to handle a problem.
I created a file to keep all these comments for future reference.
Thanks everyone.
Kevin P.

[mitch]

Hi Jeff-

I'd second/third most of what's been said about tool geometry- especially rounding off the heel and polishing. However, some materials are just plain AWFUL to cut. Your best tools are patience, a large vocabulary of swear words, and an understanding client.

Years ago I ran into a folder with 416SS bolsters that had the oddest consistency. I could easily cut medium to light lines with a sharp 90, but any attempt at hogging deeper cuts to relieve the background was next to impossible. The steel wasn't so much 'hard' as it was 'tough'. I clearly remember explaining to the customer (why the bill was going to be higher) that it was like cutting hard frozen ice cream. Easy to make light scratches in, but impossible to get a deep scoop. It never took me so long to remove so little background as on that knife...