Razor Rock *update: sharpening video*

[scdub]

Hi All,

A few weeks ago I posted some pictures in an old thread of a large chert rock I found that I was hoping I could make into a straight-razor finishing stone.

Thread 'Rocks'
https://www.bladeforums.com/threads/rocks.1859813/

Well, after many hours of work, I finally got it essentially finished this morning, and I can say that the answer is yes - it’s a razor stone for sure (= extra fine “grit” and no inclusions)!!

I’ll post more in the next few days, but I wanted to share my excitement with a quick pic and a little video for now. I’ll be sharpening my razor with it for the first time tomorrow morning, and this is the first stone I’ve ever found (out of dozens) that’s suitable to finish a straight razor.

Keep ‘em crispy!

Scdub

 

[garry3]

What kind of progression are you using?

 

[catspa]

Nice!

I’d have my lapidary friend slab that into 3/8” slices, did that with a lump of moss agate and found it quite satisfactory.

Parker

 

[scdub]

What kind of progression are you using?

Because this is a special stone, before I started grinding, I used a towel, a lazy susan, a laser level and a marking pen to create a flat section that was parallel to the apparent grain of the rock. In hindsight, using a red marker was a bad idea and it was a bit difficult to remove in one section - should have used a neutral color…


I then used a 4” diamond cup wheel on an angle grinder. This chert is so dense and hard that I thought my wheel was getting worn out and bought another one. Bad call - the new one is substantially worse than the old one (seems like less diamonds in the steel).


I’ve never experienced anything like this - it was sparking/heating up the whole time and it was extremely slow going.

After the angle grinder I moved to 16 grit silicon carbide (available online) on a $2 paving stone:

Then on to diamond plates (thanks Mark4444 !!). These 10” plates are available online in different grits for under $30 each. I used some weights to speed grinding and used 100 and then 400 grit plates.



Finally I went back to SiC but at 180 grit this time and I finished the surface using another small, hard sharpening stone to grind with.

To back up a little - here’s the rock as I found it. It’s entirely translucent and inclusion free as far as I ground it. There are hairline cracks throughout the stone, but with the exception of some surface chips on one side, these cracks appear to be very old (millions of years) as they no longer hold moisture and cannot be seen as cracks under magnification.

I’ll post up sharpening video soon, but I already tried it on my razor this morning and it worked great.

 

[running bird]

You’re doing the lord’s work scdub. I also like rocks and I like sharpening, this is something I never even thought of until seeing this thread and your other one.

I have half gallon size ziplock bag packed with various cool rocks from different parts of Moose Head Lake up in Maine. I’ll be inspecting them all more closely soon to see if I got anything that’s sharpening worthy.

Now instead of just bothering my girlfriend with neat rock facts when we’re out hiking I can include information as to their sharpening stone potential along with it. Accelerating my eventual death

 

[scdub]

Hi again,

I finally set up a tripod so I could record a quick sharpening video.

I compare my razor stone to something many of you will be familiar with - the Spyderco Ultra-Fine ceramic bench stone.

If you listen closely you will hear that the razor stone is a bit finer than the Spyderco (which used to be my finest stone, and which I used to use to finish my straight razor before stropping).

I’ve used my new chert stone many times now and it’s my favorite.

Another note - I ended up getting a third diamond plate at 1000 grit which I used before a 180 grit SiC final finish on the razor stone surface - using this final plate allowed me to get the stone even more flat.

 

[SwissHeritageCo]

Awesome stuff.

You should try cutting off some smaller pieces and making some pocket stones for comparitive testing. Very cool!

 

[scdub]

Awesome stuff.

You should try cutting off some smaller pieces and making some pocket stones for comparitive testing. Very cool!

Thanks!

I’m thinking about trying a large diamond wheel on my miter saw, but I think it spins too fast - need to research this - might be able to get a speed modulation device.

Definitely not going to do any more cutting on this stone however. It came out as well as I hoped for so I’m quitting while I’m ahead.

I think I will try to make a wooden base/stand however - maybe lit from behind the rock like a salt lamp…? We’ll see.