Grit estimate

[blade dude]

Does anyone happen to know the grit of this stone?

 

[Obsessed with Edges]

'Carborundum' is silicon carbide by another (trademarked) name; see the company's history info linked below. In a pocket hone, it's likely somewhere in a 320-400 grit range, maybe a little coarser, perhaps down to ~260 grit or so. This is common in hones like this, which generally would be used for relatively light touchups to an appropriately toothy, but still not too coarse, working edge. Should be a pretty decent hone. I have a similar silicon carbide hone in a single-sided 'Fine' grit from ACE Hardware, and it's likely around ~320 or so.

http://www.carborundumindustrial.com/CarborundumHistory.aspx



David

 

[bucketstove]

No, but its coarse, probably around 100 grit, no more than 320 grit
I did read in it used to sell for 0.15-0.25 dollars, or about $3.59 - $5.59 in today's money,
about same what a new pocket stone costs today, or one of these old ones can sell for on ebay

 

[blade dude]

I've seen these selling eBay for triple that. It felt really course but haven't tried it yet. Anyone know of similar ones around 400 grit that are relatively inexpensive?

 

[Obsessed with Edges]

I've seen these selling eBay for triple that. It felt really course but haven't tried it yet. Anyone know of similar ones around 400 grit that are relatively inexpensive?

The one I mentioned from ACE (pic below) is likely close to that; they're only around $4-$5 or so.

(...and try out the one you've got; a lot can be learned by looking at the finish left on the bevels. It may not grind as 'coarse' as it looks/feels, as is the case with a lot of stones.)

David

 

[jpm2]

Both of the stones above look closer to 100 grit.
I have a Norton jb8 combo, 100/280. The 280 side is much finer than the above.

 

[Obsessed with Edges]

Both of the stones above look closer to 100 grit.
I have a Norton jb8 combo, 100/280. The 280 side is much finer than the above.

No; this shows that looks can be deceiving. The ACE stone is much finer than that. I have two of them, and they grind more equivalent to ~320, or finer with some use. Very similar to the 'Fine' side of Norton's Economy stone (in SiC), which is also much finer than 100 grit. Norton rates their Fine SiC (Crystolon) roughly between P320-P360 (as compared to wet/dry sandpaper). In my own use of it, it compares very closely in the finish to 320-grit wet/dry. In fact, to the OP, that might be a pretty good way to figure out what grit finish your stone is grinding to; use varying grits of wet/dry paper on glass or stone, and compare the finish left by each to the finish left by the stone. The hard backing under the wet/dry paper will most closely emulate grinding on a stone.


David

 

[jpm2]

No; this shows that looks can be deceiving. The ACE stone is much finer than that. I have two of them, and they grind more equivalent to ~320, or finer with some use. Very similar to the 'Fine' side of Norton's Economy stone (in SiC), which is also much finer than 100 grit. Norton rates their Fine SiC (Crystolon) roughly between P320-P360 (as compared to wet/dry sandpaper). In my own use of it, it compares very closely in the finish to 320-grit wet/dry. In fact, to the OP, that might be a pretty good way to figure out what grit finish your stone is grinding to; use varying grits of wet/dry paper on glass or stone, and compare the finish left by each to the finish left by the stone. The hard backing under the wet/dry paper will most closely emulate grinding on a stone.

David

The pictures must indeed be deceiving.
Here's my actual Norton jb8 100/280.

 

[blade dude]

It felt really course while sharpening my knife. Do I need oil or is it an option if need finer cuz I read it is option of need finer. Either way it's put a hair shaving edge on my delica that doesn't look polished but doesn't look toothy either

 

[blade dude]

Also does anyone ever actually keep it in their pocket day to day or only during camping or it stays in a bag or what?

 

[Obsessed with Edges]

It felt really course while sharpening my knife. Do I need oil or is it an option if need finer cuz I read it is option of need finer. Either way it's put a hair shaving edge on my delica that doesn't look polished but doesn't look toothy either

That's consistent with what I was describing in my estimate of the grit (~260-320), and also consistent with the behavior of a pocket stone, which are usually configured to leave good working edges on their own without going too coarse. They'll often emulate a lot of factory edges on knives. A 100-grit edge would look & feel pretty obviously ragged by comparison.

If the stone is dry and looks like it hasn't been oiled before, you have options to try out if you want to. I've used SiC stones like these dry, or with some mineral oil, or even lubricated with some dish soap & water. With oil, they work fine; but more and more, I'm liking using the dish soap & water for bigger grinding jobs, as it keeps the stone very clean during and after use. For occasional light touchups on the fly, they work well just used dry. Try it out as you see fit; SiC stones are pretty easy to get along with. If you sharpen a lot of non-stainless blades, using the oil instead of water could help in controlling rust issues, both on the blade and in the swarf collected in the stone over time (though the oil, over time, will tend to make the stone collect and hold MORE swarf, and using soap & water does a better job flushing that out of the stone with each use). The rusting possibility is relatively minimal though, so long as the blade doesn't stay wet too long; just wipe it down periodically with a towel while sharpening. I wouldn't let that influence the choice of lubrication much, if at all, UNLESS you are seeing some rust developing quickly as you work.


David