Interesting graver sharpening phenomenon

Sam · May 18, 2013

DJ Glaser at GRS and he was telling me of a graver sharpening experience of Alexandre Sidorov of Belgium. Alexandre was having difficulty keeping gravers from breaking when diamond setting a really tough stainless steel watch case. If you've ever seen Alexandre's gravers, they are polished beyond perfection.

After continued breaking of the graver Alexandre did something contrary to his mirror polishing of the graver's surfaces and resharpened with a coarse "satin finish" condition as he refers to it, and this extended the graver's life substantially.

I've been working on a stainless steel Rolex back which is also really tough steel. About 5 minutes into the job my perfectly polished C-Max EG120Â° graver broke. I then resharpened the face and heel on a 600 grit lap and left it at that. I continued engraving the rest of the case back without having to resharpen. I was very surprised.

Alexandre suggests stopping at 1200. My worn 600 seemed to work pretty well.

I can't explain why this worked, nor can DJ or Alexandre. Alexandre swears this satin finish extends graver life, and based on my one experience I have to agree.

Anyone else ever notice this?

Mike Cirelli · May 18, 2013

I recently did a Beretta pistol that was hard as a rock and did the same thing.
It was crushing my C-max when it was polished. I kinda of did it by accident because I got tired of polishing it every time it broke. I had to inlay it so I figure it didn't need to be polished anyway. I agree it worked better than a highly polished graver. I used it right off the 600 wheel.

rayf24 · May 18, 2013

Guys let me explain why this is so I shall try and keep it simple you have to think down to near the nano view here go's when the graver face and heel have a courser grind the micro grooves on both face and heel act like jaws or barbs of a spear that hold the graver in position and each little barb act like a point of its own if you have ever tried putting a very smooth wedge in a hammer handle when replacing it they tend to ride out yet a course ground one will bite in and not side back its all the little grooves and barbs that hold it so what's happening when mirror polish is applied to the graver tip you have nothing to hold it in the last strike or blow position of the hammer or power tool remember this is at the microscopic level when polished this allows the tip to slip back and take up a new position then when the next blow comes the tip which is not in full face contact then has side loads which will at some time be to much and starting a nano micro hairline crack leading to tips breaking THINK MACRO and you will get your head around it I found this also about 25 years ago in OZ when drilling stainless steel castings when the drill was sharpened with very fine wheel chipping and tip breakage happened but when ground with a very course wheel one could drill 6 to 8 holes about 7 inches deep before a resharpen as opposed to 1 or 2 holes again each little groove acted like barbed tooth stopping micro chatter and holding the cutting edge in place.
Sorry for being long winded but thats about a simple as I can explain it again you have to think micro.
Hope this helps.
Ray

SamW · May 18, 2013

I tried the exact angles/high polish approach some years ago and the point chipped rather fast. Never spent the time to do that again and went back to my old 600 for the face and 1200 for a tiny heel. Has worked well enough for me though I usually try to skip the really hard metals.

mrthe · May 18, 2013

Sam one question,if you don't need a very bright cut you should use mirror polish in your gravers too? in steel too? i should sharp my gravers no more than the 1200 and with carbalt and the parallel heel the cuts are bright enough,( o have to say that in the 99% i blackening my works with ink and is better don't have a bright cut i think) i feel the same when i over polish my gravers and i work in materials differents than silver or gold ,more brokes ,but i'm not have a lot of experience for this reason my question,in steel i preferre a mirror polish only for bulino works where i feel a great difference but for steel is better have a mirror polish too?

Jared Eason · May 18, 2013

Ha this may be a solution to my stainless issues. Other than me not being experienced. Lol

Arnaud Van Tilburgh · May 18, 2013

Sam, Chris DeCamillis already told about that here in a tread about engraving and stone setting on stainless steel watches.
The Chris HSS gravers I ordered time ago, I sharpen them finishing on a “worn off” 1200 diamond wheel.
And like you said and Alexandre experienced, gravers shaped that way not only cut better, they also last longer without breaking.

My daughter Lola uses them all the time for flare cutting on Ti

arnaud

Dave London · May 18, 2013

Very good info Sam, this needs to be a sticky. Thanks

Willem Parel · May 18, 2013

Dave London said:
Very good info Sam, this needs to be a sticky. Thanks

I second that !

mtgraver · May 18, 2013

Ray,
Thanks for that explanation it makes some semblance of sense. I wonder if the surface area in contact is also an effect? coarse vs high polish or more vs. less if you will. I find this a fascinating subject and solution.
Mark

Sam · May 18, 2013

Thank you Ray. Nice explanation and it sounds valid.

Mrthe: I cut a lot of jewelry so I tend to polish my gravers to a bright finish. Of course there are times when this isn't necessary, but most of mine are brightly polished. I think 1200 is fine for most things except where you want super bright cuts required in jewelry engraving.

Arnaud: I'd forgotten Chris mentioning this. The reason I tried it this time is because it was fresh on my memory from my conversation with DJ a short time ago. Obviously others have known this but I'm not one of them

One thing for sure, I'm glad we're talking about it so others can benefit.

rayf24 · May 18, 2013

Mark
Next time your cutting some stainless and you have sharpened your graver have a look with extreme magnification if you can and make a mental note of what it looks like then when you find what you think is the tool getting a little blunt but it is still cutting ok its just lost its edge have a look at the tip with extreme magnification again you maybe suprised to find the tip is not worn but chipped.
Ray

rayf24 · May 18, 2013

Sam
The finer and brighter the polish the finer the tip becomes and the finer you go the more fragile it becomes one has to think in ever decreasing size at the magnification that most of us are using it cant be seen I know its hard to get ones head around the concept but we can over polish wasting time and money having to resharpen and polish again which and leading to the problem discribed when maybe just shapening with 800 or 1200 grit would have been ok.
Ray

rod · May 18, 2013

I was about to write what Ray wrote so nicely, a rougher cutting edge is serrated at the micro level, and tends to do lots of tiny chips right up front, this lessens the stress. You can order roughing end mills, at the macro level, they have broken up edges.

Rod

Gemsetterchris · May 19, 2013

I've been avoiding "mirror finished" for a while now, so long as I get a resonably bright cut that'll do.
For me a smooth clean looking cut is more important.
Everything I do ends up getting polished/ rhodiumed anyway.

KCSteve · May 19, 2013

I wonder if the 'rough' surface is also helping stop the spread of any cracks as they start to form. With a high polish, once a crack starts there's nothing to stop it until it hits the other side. With a bit of roughness the crack is interrupted almost as it's starting so nothing breaks until enough imperfections accumulate to become a 'real' crack.

BrianPowley · May 19, 2013

I haven't polished a graver for years---except for when working on "Bright cutting".
I think my "Epiphany" came one day when I realized that I don't polish my carbide lathe tools. And they take a pounding compared to engraving.
I do find that using the ceramic lap is mighty handy for putting on the heel.

Barry Lee Hands · May 19, 2013

I have just been polishing to 600 on carbide for a long time, and it works fine.
When I took Siderovs stone setting class he mentioned this, and I could not disagree.

Andrew Biggs · May 19, 2013

I'll swim against the tide on this one.

I've just finished cutting a fully engraved watch made of 316L stainless. Case, back, rotor and bezel.

Using a C-max 1.8mm graver on an Easygraver 120 parallel heel, I sharpened the face with a 1200 grit wheel. Heels on a ceramic lap then put a very slight 55 degree face on the tip with a ceramic lap. Then just gently wiped the point over the ceramic. It sounds a lot but it was real quick.

Net result was for the entire watch (except the bottom half of the rotor) I sharpened twice. Once in the beginning and once near the end for some lettering.

Cutting the bottom half of the rotor which is extremely hard metal, I sharpened twice. The first as has been suggested above with a 1200 wheel. The tip broke almost immediately. So I went back to what I was doing with the polishing on the ceramic and cut the rest of the rotor no problem.

So what does all this mean??........I have absolutely no idea

Cheers
Andrew

Frank P · May 20, 2013

Ray24
thanks for the explanation and sharing your point of view...
I just wanted to point out that your entries are a hard read ( for people of who english is not the native language..).
Some use of periods, commas and capitals would make it much more pleasant, :thumbsup:

thanks for your comprehension

Interesting graver sharpening phenomenon

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