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Bill Haumann
05-27-2011, 7:33 AM
What is involved in getting a used (or new I suppose) oilstone up to ideal condition?

- Bill

David Weaver
05-27-2011, 7:42 AM
If it's out of flat, that'll be the worst part because they're hard.

The only other thing you might have to do is get the pores of a stone unclogged by boiling it to get the crud out.

If it's way out of flat, you will have lapped all of that crud off, or at least enough of it so you'll have a pretty fresh surface.

That goes for new, too. Sometimes they're flat, sometimes they're not. You'll want to lap a new stone when you get it, anyway, or at least check it for flatness.

Andrew Pitonyak
05-27-2011, 8:32 AM
With what do you lap these hard oil stones? Diamond plate? Another oil stone? I am guessing that sandpaper will not work.

Just curious...

David Weaver
05-27-2011, 8:59 AM
I used a diamond hone, and tried a lap that I use for planemaking (an 8x42 glass lap with psa mirka paper). If they are way way out, you can start off with a belt sander (wear a mask).

My only two old stones were worked by a careful craftsman, and they were very close to flat. Of the three new ones i got, the hard black or surgical black or whatever its called was the worst off, and every few times I use it, I run over it some more with a 220 diamond hone (i don't use it very often). If i recall, the sandpaper on the lap was faster, but it was hard on the paper, and it is a monster big stone (12x3) that I found in a bargain bin. The corners still fall away a little on it. It bugs me to keep lapping it, because it's a fairly coarse stone and aggressive cutting stone on plain carbon steel when it's freshly dressed (especially when you're used to shaptons), but quickly wears finer and slower with use.

Strangely enough, the surgical black is a brand name stone, and the other two new ones (a soft and hard arkansas) that I got from a stone cutter in arkansas who calls themselves "natural whetstone" (no relation to them), were just absolutely dead flat when I got them, even with a nicely finished surface. And the guy gave me a break and sold me both (10x3x1) for $50 - absurdly cheap.

so, I guess it's a crapshoot.

My brand name stone is a halls. I'd expect maybe that nortons would be dead flat. Never even looked at "dan's", they have a pricing philosophy that isn't compatible with my buying philosophy.

george wilson
05-27-2011, 10:14 AM
We all had the old large hand turned sandstone grinding wheels in the museum. I taught others to just lay their wheels flat,pour on water,and you could even lap a black Arkansas stone flat pretty quickly on the sandstone,soft as sandstone is. You might could get a slab of sandstone from a local stone supplier. Or,just use abrasive paper stuck down on a lat surface like glass,or a cheap granite surface plate.

I'd be paranoid about using a belt sander. Don't want a little layer of abrasive dust getting on my metal lathes,etc..

Roy Lindberry
05-27-2011, 10:50 AM
they have a pricing philosophy that isn't compatible with my buying philosophy.

Now that's a great line. I'm going to have to borrow it next time I get the chance.

David Keller NC
05-27-2011, 11:01 AM
My brand name stone is a halls. I'd expect maybe that nortons would be dead flat. Never even looked at "dan's", they have a pricing philosophy that isn't compatible with my buying philosophy.

I've kind of wondered about this. I know that there are different "grades" of novaculite, and I'm wondering if the fairly large price differential is simply that Dan's sells firsts, and Hall's sells seconds. That grade distinction might make no difference whatsoever to a user, but then again it might - uniformness of grit size, for example. Does anyone know?

David Weaver
05-27-2011, 11:20 AM
The halls stones were claimed to be firsts, as were the ones that I got directly from the cutter.

Dans does sell seconds, too. .... (actually, that appears to be incorrect - just checked their site. Halls sells firsts and seconds of the HTAs - not of the others, but they claim that it is an issue of nicks, or coloration, and not the fineness of the stones).

When I was reading and researching where to get stones, it seemed like norton sort of has the market cornered on HTAs (especially ones that looked good for a good price), and theirs were considered the best. I don't know if that's still the case, but it had something to do with who owned what land.

I kind of wish I would've just gotten an 8x3x1/2 HTA norton instead of a 12x3 surgical black, i couldn't resist the lure of a big stone.

Some of my slips are HTA (norton), and I would say their fineness is not a lot different than the halls black stone, both fresh and worn. I probably have some built in bias about what a finish stone should be because my normal routine for a hollow ground edge is two stones with the second one being a 1 micron shapton stone. With some wear on the surface of the halls stone, it's probably something like a 6k waterstone, but it cuts much differently, and it's a bit disappointing compared to shaptons.

James Taglienti
05-27-2011, 10:17 PM
Ive flattened my novaculite, black, and translucent arkansas stones on a stationary belt sander with 100 grit red (garnet?) paper. None had a dish much worse than 1/16 and it took about 30 minutes to do all three, but the belt was shot afterwards. Ive also used the same sander for a bunch of natural water stones with good luck. I tried it on carborundum and the stone definitely won.

Terry Beadle
05-28-2011, 12:18 PM
I used a 220 water stone to flatten my HF bargain oil stone. It probably wasn't required. I could probably have used a cement block with the same results.

So I guess I'm agreeing with Mr. Weaver, get it reasonably flat with a coarse medium, keep the crud out, but use water to flush it while you are getting it flat.
If you are wanting to flatten a black arkansas level of oil stone, I would use a xtra course DMT diamond on it after getting it flat with a 220 water stone. Most blacks you buy would not require the 220 grit treatment I think.

Maintain it's flatness with the DMT black ( xtra coarse ) and you should be good to go.

Tony Zaffuto
05-28-2011, 4:40 PM
In my flea market and tool sale/tail-gaiting travels, I have picked up many oilstones (and will continue to buy them, cause they're usually only a couple of bucks). I've gotten some terrific stones, that amaze me with their ability to quickly put edges on my tools (My likes are mainly O1, with a bit of A2 steel in my blades).

I generally clean my newly acquired stones by soaking with oven cleaner and then washing in very hot water & brushing. I don't get to anal about flattening, as sometimes having a dished stone is really nice for sharpening a pocketknife or gouge. But when I flatten, I use a piece of coarse (think 80 or 100 grit) zirconia sanding belting (I got a bunch of these belts from Supergrit in Gettysburg, for next to nothing). Works very quickly!

As an addendum: in the event any of you every get the bright idea to clean your stones in SWMBO's dishwasher, don't do it! It leaves a greasy haze on every surface that took me hours to clean off. The stones were clean however, so it's up to you!