Graver Grind

[Sandy]

Several months ago I was engraving a cylinder that was really hard steel. I was breaking the graver about every millimeter or so. I was using a 1.8mm C-Max. As I was grinding a new tool I thought about a thread Carlos had posted about not grinding the two bottom sides. So I left a little of the radius in place and then put the heal on. It left a small triangle behind the point. I wanted to try it with out changing this triangle so I dubbed the point at 90 degrees with only to very short swipes across my ceramic wheel. The picture is not so great but shows the results of the grind. It will fail. However when it does it is not a catastrophic failure. The fracture general stops at the rear edge of the heal or less. I have been working on some very hard Rugers of late and this grind has been a god send.
Sandy
P.S. That is not a flat on the bottom it is the original radius of the C-Max blank.

 

[silverchip]

Interesting, I would think without meeting in the middle that it would just kinda plow through and not really cut.

 

[tim halloran]

Sandy: I have had the same problem with the round c-max carbide. What i do is sharpen with the easy graver sharpener, putting both angles on the graver, dub the tip just slightly. Then i put the graver into my multi angle sharpener and set it at 17.5 degrees with the cutting edges pointing down, then very lightly swipe the bottom of the graver across my ceramic lap. This puts a very small flat spot on the bottom of the graver. This creates a very strong point, you don't need much. I also have several gravers with varying widths of flat spots on the bottom which i use for background removal. You can follow the borders and cut around the scrolls with this and it leaves a nice little flat bottom cut alongside your main cuts. This helps keep you from damaging the side walls of your cuts.

 

[jerrywh]

I put a real small flat on the bottom of my Cmax gravers. It helps a lot on hard stuff.

 

[Sandy]

Silverchip not sure what you mean by meet in the middle. It cuts clean and has a smooth chip form and curl. If you are refering to the back part of the heal it does not cut there. It cuts with the leading edges where the heal and face join. The point is reinforced by the small triangle that forms behind the cutting point when you grind the heal.

Tim. I was doing something similar to what you have described. But when I was cutting hard gun steel I would still get catastrophic failure where I would lose as much as an 1/16 to 3/32 + of an inch. This grind has stopped that.
Sandy