Thread: I Found It Over There

Originally Posted by joamo

I'm thinking of trying a diamond cup wheel to knock off the high spots on one of the quartzites.

The good thing is they really take material off fast. The bad thing is they really take material off fast. I have both success and failure. I kept thinking if I could mount the grinder above a work surface and then push the stone through and have it work more like a planner that it would be superb.

Originally Posted by RezDog

The good thing is they really take material off fast. The bad thing is they really take material off fast. I have both success and failure. I kept thinking if I could mount the grinder above a work surface and then push the stone through and have it work more like a planner that it would be superb.

Now you've got me thinking, I'll post pics if I come up with a good solution.

I used to use a diamond cup wheel all the time when I was doing more stone work. My strategy was to lightly nip the stone on a 4" x 10" diamond plate to ID the high points, then grind on those a bit and check against the diamond plate again. Back and forth until I could just go to the diamond plate or some loose grit to finish the job.

Originally Posted by Iceni

Well I've spent the last week grading the rocks I picked up.

...

These are the lumps that went to the Roman fort.

Attachment 160914

Makes a change, Iceni giving gifts to the Romans...

Originally Posted by DZEC

If it’s not too much trouble, can you post a photo of the rock illuminated from behind? I’m trying to imagine how spectacular that might look.

The stone is opaque. It is not an agate or Washita type stone. Thanks for asking, I had not done that test before.
~Richard

I had two found stones that were very promising in fineness, but just too slow IMO to be useful. One was a hard slate and the other a contact metamorphosed shale (hornfels). They just didn't seem to release enough abrasive to be effective. I tried slurrying with tomos but they were too hard to really work that way. I used them with softer rub stones and slurries and they worked but so what, I could probably just use a piece of glass or granite that way as the stone seemed to supply little more that a flat smooth surface. I recently tried them with a diamond nagura slurry the way I've seen some use extra hard Jnats and WOW! what a change. I've been putting killer edges on knives with them and have yet to try a razor, but they are very impressive.

Just goes to show, don't give up on your failures. People sometimes take years to figure out purchased stones while we rock hounds tend to try something once or twice and give up.

It’s true. You have to play around a bit with every sample. I have cut quite a few that simply turned out to be hone shaped rocks.
Did you hear the on about the young geologists that took everything for granite?

I'm planning on bringing these two to Texas.

This is my "Allgäu-Slate" ...




I've found it in the bavarian mountains, the region "Allgäu".
It was laying around on the walking way together with stones which seemingly were braught here from some other place.
So it might be a "slate comming from somewhere else but living in Algäu now"

I've identified its cutting properties by putting some water on it and rubbing a kitchen knife.
It has instantly produced some swarf.
From the side it looks to me like a slate:




Lapped at home, later I've put some silicon (i know: you're jsut rolling you eyes, sorry) around to give it a good stand (currently using it to finish my cheesels and plane blade) and cut a corner off to get a "tomo nagura".



The stone is pretty hard and not easy to slurry (reminds me on Zulu Grey), its surface has a quite fine grit and is slightly porous, comparable to Zulu Grey (Zulu is still finer)






While working it develops a glossieness and I guess gets more and more finer and slower.





Interest thing: I've found a green-blueish inclusion on it the same I know from the welsh purple slates (does anyone know what is its composition?):



Here are some whet pictures:




Dimentions 13 x 6 cm, actually gives a nice razor hone size.
As I found it my razor sharpening skills were of much much lower level as today (still considering low) and my first attempts to finish a razor on it were failed.

Will give it another try on one of my razor.

Regards!

Philipp

Interesting stone, nice find!