Thread: Hindostan Hone?

Thanks Neil for the info and pictures!
The pattern and patches on the honing surface looks a lot like mine. What is the aprox grit on these, other people have said and I think I agree, it's about 6-8k, it does seem finer with oil though and definitely coarser with slurry and water.

well speaking about my hindostan stone it fall's in the novaculite family and in that progression my hindostan falls in-between my translucent or surgical black and my cf. i rate the grit of my hindostan around 12k i've seen them rated around at the low end of 9k to the high end of 12k

here are a few pic's of my hindostan stone .my stone is a darker brown with some tan and a little orange. first pic in natural sunlight second pic indoors without sunlight third pic side view without oil fourth pic side view with oil fifth pic from the top with oil enjoy -craig

Well, just to add some more to the pot. Here's mine to the left of a couple other mystery hones, and two featuring side banding. Mine is like glass on top, which has made me wonder if I didn't glaze it. But the sides are chalky like you mentioned. It slurries at the hint of friction, but I haven't really done anything amazing with it. My skills are somewhat lacking still. After I catch up to the hone, then I'll tell you what it's capable of.

It certainly does look similar to mine but I also suppose it could be another sedimentary stone with abrasive qualities.
Grit - the silica xls (abrasive particles) in the Hindostan were, at one time, reported to be approximately .02mm - 20 micron. About double the size of the particles in an Arkansas stone. Because the particles are not as closely packed in (density) the stone was referenced as being 8 times more coarse that an Arkansas.
I just now came back from the kitchen, having put my soft Ark up against my Hindostan with a beat up Torrey.
The scratch pattern from the Hindostan is deep and rough, where the scratches from the soft Ark show a tighter patter, they're not as deep and the bevel was hazier overall. The soft Ark was able to remove all of the scratches from the Hindo with less than 40 half-strokes. The cutting edge from the soft Ark seems to be refined to a higher degree and I would suspect that it would give a better shave if I was going to really give it the acid test. What I think is that my Hindostan is better suited to putting an edge on knives. I don't see it being part of a progression for razors here but if I was going to attempt to do that it would be early on...

I'd be interested to see that report, if you can remember where you found it. I've done a little reading about it, and kinda came to the conclusion that a lot of different ratings were applied. As you could buy the stone for brick laying, or for tool sharpening, or for tombstones, or of the quality useful for a razor. Using my stone on an antique Ontario Cutlery kitchen knife got me nowhere. Ahh you see? I can't accept it. I WANT this stone to be special. hahaha.

The Annual Report of the Geological Survey of Arkansas for 1890 Vol III

You can find it in Google books; there are other volumes, but that's one I saved. Don't know how accurate the data is compared to what would be produced today, but it's interesting reading at any rate. I would assume the information to be close-enough though.
I don't know enough about the Hindostan to say whether or not there were 'grades' available - but I've not seen anything that alludes to that. Variances with natural hones is common - but to what extent with these particular stones, I don't know. I do think I read about some stones being whiter though.
If your stone wouldn't cut the carbon steel on that kitchen knife then I'd suspect that it's glazed or something, Mine cuts pretty well...must use oil or soapy water though.. I used it dry once and it loaded up pretty fast.

If I raise a slurry with a DMT, mine cuts REALLY fast and the slurry turns black, with just water it will start to discolor after about 40 laps, with oil its feels like a Coticule with water and feels like a finisher

According to some of the old data (which may be accurate, or not) the particle size varies: from 0.010mm to0.325mm, so 0.02mm is seen as a theoretical average size only. Actual specimens may be coarser or finer. As Gamma says, 0.02mm converts to 20 microns, and according to what micron/grit conversion chart you consult that converts to somewhere between 800 and 1k, which is not my experience. The ones I have tried have ranged from around 9k to at least 12k.

The problem is probably the same as that encountered with arkansas stones - you cannot use a grit rating system. The cutting particles cut finer or coarser according to how densely they are packed, so the only reliable indicator of fineness in these circumstances is to use specific gravity as a determination of fineness - the more closely packed the particles the finer the cutting action and the denser the stone.

Regards,
Neil

I think Neil is spot-on here.
This is why I try to avoid relating the performance of a natural stone to a grit rating. I see the need for a comparison from one stone to another - but my mind is too linear to accept referencing an Arkansas stone as 12k or higher, when I believe the particles are actually more like 1.4k.
Along with specific gravity, and/or density of abrasive - the shape of the xls, xl friability, and how the basic structure of the stone factors in to the equation must be considered. I would imagine that measuring specific gravity would be for comparing specimen to specimen - not Hindostan to Charnley Forsest though.
Using the average size of the particles seems to be/have been the common method of comparison across the board. The Arkansas was said to have 0.01 mm particles - and I'm convinced (although not 100% positive) that there were a good number of stones that had an average number of larger or smaller particles. My guess is that since honing a razor or sharpening a knife wasn't considered so uber-critical to most people and a declaration of 'average' performance was sufficient.
Proof is in the pudding I suppose - so the only way I'll really know what the best edge this Hindostan of mine will be like is to shave with a razor I finished on it.
I hate sacrificing a known-good edge though... I have to get over that. I can't keep buying razors for the sake of testing stones.