Sandpaper Sharpening

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Stephen LaMantia

Nov 1, 1995, 3:00:00 AM11/1/95
[No, you can't sharpen sandpaper. And please don't
ask me how I know that.]

[Required warnings:]

[If you don't like sharpening tales, or sandpaper, or
handplanes, or any deviation from simple declarative
sentences, please don't read this post. Also, it's a
process gloat, and it's windbaggy, so be forewarned.]

[And if you prefer one-clause synopses, here: "I sharpened
a plane blade with sandpaper." Now move along now.]

For anyone else:

I recently emailed a few folks about some attempts I made at
sharpening a plane iron with sandpaper. Some suggested I post my
story to the group. So here it is.

(Rich and David, I've pretty much rehashed my email to you guys
here, so you can move on out now, too.)

Let's see. Who's left? Oh.

Dear Mom,

I've recently been experimenting with using sandpaper for honing.
I had been getting tired out with the oilstones getting unflat and
glazed and needing to be lapped all the time, tired of oil all over
the place and on my hands so I couldn't even scratch, tired of
having to clean the stones after each use, tired of having to keep
a conscious effort going to distribute wear on the stones evenly.
So tired of all of this.

So I started thinking about abrasives and abrasive action in
general, and read up a bit, and asked around, and found out that
there's nothing different, in principle, between sandpaper and an
oilstone. Silicon carbide sandpaper (i.e., wet-or-dry) goes up to
600 grit in the hardware and woodworking stores, but up to 2000
grit in the automotive finishing stores, as I learned from David
Opincarne, a local rec.woodworker and admitted metalhead who works
right here at the school and who sent me some 1200-and 2000-grit
samples and who's recently been helping me greatly to understand
the secrets of metal. For example, did you know that to produce
high-carbon steel, crushed bone from the skull of an infidel is an
excellent carburizing agent? Me, neither. Or that hardening the
steel in cutting blades is achieved by the sudden and even cooling
of the blade, and that the best known way to achieve these dual
goals is to quench the blade in the still-living body of an enemy
warrior? Same here; I had no idea. David's been teaching me a

Me and him and some other wreck.the.woodwork folks had been talking
lately about this abrasive business, and it got onto sandpaper
somehow, and so I decided to test something out. For the
sharpening-with-sandpaper experiment, I used a slightly-pitted 2"
wide jack plane blade that came with an old beat-up Stanley Bedrock
#605 I bought last year at a tool swap. The bevel on the plane
iron had been somehow ground *concave* by the previous owner (or
else it just wore that way), so I first straightened the edge out
on the grinding wheel, grinding in straight at first so as not to
create a thin edge that would burn, and then grinding in a bevel
but stopping a bit short of a real edge, again to prevent burning.
Because of this care not to burn the steel, this grinding goes slow
and light, but it's time well spent.

Time now to lap the back behind the cutting bevel. I took a page
out of the plane-sole lapping book -- figuratively speaking of
course, you should never tear pages out of a book -- and used very
light coatings of 3M "77" spray adhesive to temporarily glue small
1-1/2" x 3-1/2" rectangular pieces of sandpaper along the edge of a
sheet of 1/4" plate-glass. The paper I used was Aluminum Oxide in
grits 50, 80, and 100, and Silicon Carbide (wet-or-dry to you
laypeople) in grits of 150, 180, 220, 320, 400, 600, 1200, and
2000. The plate glass was placed with its edge flush to the edge
of the workbench.

I lapped the end one inch of the back of the iron on each grit in
turn. I didn't use any water; I just went at it dry. So as I
lapped -- can you call it lapping if it's dry? -- anyway, about
every ten seconds or so I'd stop and brush off the sandpaper with a
whisk broom and wipe the blade off on my shirt. (On the coarser
grits, I found that a dustbuster vacuum actually cleaned up the
paper quite thoroughly, much better than sweeping it off, but this
sucking advantage disappeared at around 220 grit.) Since I
progressed through the grits so gradually, I found I had to spend
only about a minute or so on each grit, including the suck-down and
sweep-off and shirt-wipe time.

One trick to efficiency is knowing when you've lapped the back
sufficiently on each progressive grit. I had previously had
trouble gauging this, and didn't know how to tell when enough is
enough. Thanks to a clever suggestion from Jeff Gorman, I tried a
trick that seemed to work wonderfully. I have a cheapie Radio
Shack 30-power hand microscope -- "microscope" sounds impressive,
but it's only $10, although I forget where I got it from -- and
used that to tell when the striations from the new grit had
replaced all the striations from the previous grit, and when they
had, I stopped there and moved on to the next grit.

About ten minutes after starting, I had gone from 50 grit on up to
2000, and there was a mirror finish on the back of that iron the
likes of which must be seen. The back of the iron became so shiny
I could count my nose hairs in it; 98 on the left, 79 on the right,
but 109 and 85 if you count the white ones.

I then jigged the blade in a Veritas honing jig -- which, by the
way, Mr. Lee, should be called a honing fixture, not a jig, since a
jig's for holding a tool and a fixture's for holding a workpiece
and in the sharpening operation the plane iron, while usually
thought of as a tool, or as a part of one, is actually in this
instance the workpiece -- man, near-terminal digression there,
almost lost it for good; Boy, snap out of it! -- I clamped the
blade down in the Veritas blade-holder device, taking care to have
the hollow-ground bevel resting on the glass perfectly along both
edges of the hollow grind. I then adjusted the microbevel cam on
the jig up to its full two-degree microbevel setting -- Robin, tell
your uncle that Steve said "way to go, old dude" -- and honed away
on the 2000-grit. Even though I had not ground a sharp edge on the
primary bevel with the bench grinder, even on that little slip of
fine 2000 grit it still took only about another couple of minutes
before I had a nice sharp little 1/64" microbevel gleaming back at

I flipped the blade over on the sandpaper several times, hone and
lap, hone and lap, each time gentler and gentler, to remove the
little bit of wire edge. (Which, by the way, as a result of using
such a fine grit must have been so tiny that it was very hard to
see or feel, so pretty much just from my awareness of the process I
assumed it was there.)

The resulting little thin secondary bevel was shiny. I mean
*clean* shiny, like nothing I'd ever seen before. Unlike the
secondary bevels I'd previously coaxed out of my hard white
Arkansas stone, this one was unbelievably Shiny with a capital S.
I mean *clean* shiny, like nothing I'd ever seen before. Oh, I
said that already. Okay, it's hard to describe; about the best I
can do is to say that it looked almost *liquid* when you catch the
light on it just right. I mean, it was so darn clean and shiny
that it takes ten lines just to say it was so shiny it's hard to

Of course, shine is not the ultimate goal. But sharpness *is*.
Still, they equate. The more shiny, the more uniform the surface
is microscopically, and the closer to the geometric ideal of a
*line* is the edge, and hence the sharper it is. Cool. I mean
*COOL*!!! I was trembling in my Mickey Mouse boots in anticipation.

Hell, this cutting edge looked downright *dangerous*! I didn't
dare touch it. But yet, there was still something I just *had* to

I removed the blade from the jig, and anxiously tried the old
cliche "cut a finger off before you can notice and bleed all over
your screaming wife in the car on the way to the hospital" test.
Oops; no, wait. Sorry, that's the wrong test, for those other
kinds of tools. Sorry. For the Neanderthals, it's the "shave some
arm hairs off" test. Now I've done this test before, on other
blades sharpened up on white Arkansas, and while these other blades
would pop *some* hairs off the back of my wrist, many other hairs
would just bend on over down under the blade's edge (probably from
the sheer weight of four prepositions in a row), and those hairs
that *did* pop off would do so quite painfully, as though the blade
was more grabbing the hairs and *ripping* them out, and I could
feel every one of them offering their stubborn and vengeful
resistance. Not much fun, and nothing to be doing voluntarily in
front of others.

But the edge on this blade was something else! Not only did it cut
off every little hair in its path with total ease, but it didn't
hurt at all. In fact, I couldn't feel a thing; for all I could
tell, there were no hairs there in its path to begin with. But of
course there were many, since I'm Italian and also since I could
see the fallen hairs all over the back of the blade. And my arm
where I had shaved it was a smooth as a non-Italian baby's butt.
Again, man, this had gotten downright *frightening*.

But of course, the ultimate test of a plane iron's sharpness is
what it does on wood. So I put the blade back into the plane, that
old early-model Bedrock jack, which I've not yet tuned in any way.
I tried it on the edge of a piece of pine, and as I adjusted the
blade for the finest cut possible, it glided through the wood with
no effort. None whatsoever. In fact, it almost seemed like the
plane was pulling itself along, or that the wood was *wanting* to
be planed and was throwing itself into the blade -- no, I've not
read Krenov -- it took that little effort.

I ended up getting a shaving that was so darn thin I could read
newsprint through it easily. Unbelievably easily. So easily, in
fact, that I thought for a moment about taking the iron back on out
of the plane and putting the shaving over the shiny part of its
back and counting my nose hairs again, but by this time I had grown
weary of counting nose hairs, and of my concerned wife repeatedly
asking me why I was doing that.

I thought, no way, this can't be! So skeptic that I am -- I'm so
skeptical, that I can't be fully sure that I'm really that much of a
skeptic -- I put a micrometer to the shaving, and get this: it
measured .0004 thick! Four ten-thousandths of an inch! (Or, as my
eternally-pestered but forever-patient metalmentor David Opincarne
showed me, "four-tenths" in machinist talk.) No, I read the mike
right. Less than one half way to the very first line after zero.
Man! That's a cubic hair less than one-half of a thousandth of an
inch! Incredible! Amazing!

And it just gets better. For a while there, I actually thought I
had taken off another shaving that was even thinner, one so thin in
fact that it was invisible and of no measurable mass. I'm pretty
sure I did, actually, but I'm having a hard time trying to think of
a way to check this out, or even to find the spot on the ceiling
that it floated up to.

And what about the planed wood itself? Well, the surface the plane
iron left on the wood in indescribable! It's like glass! No, it's
like glass wet down with water and a tad of liquid soap added and
then some Slick-50 and then frozen and polished. And this is on
pine, a softwood! Not only that, but I then gave it the torture
test: end grain. I put the same piece of wood in my shooting
board, and had a go at the endgrain. Man oh man, I've never seen
such a smooth surface on *endgrain* in my life. And again, this is
on *pine*! The endgrain was almost as smooth as the edgegrain!
This has gotten good!

Still, having exclaimed all this, I'm making no claims to the
throne of King of the Neanderthals. I'm the first to admit that
this was kind of like when I was a kid and one year I batted a
thousand in the Kiwanis Grasshoppers when I was really four years
too young to actually play in the league but it was the last game
of the year and Dad the team manager put me up in a losing game as
the last batter just for the novelty of it and to stop my pestering
-- he figured I'd get beaned and would shut up for a while -- and
the opposing pitcher Terry Crowley the hotshot star started
laughing at me because I was so scrawny and tiny and he taunted me
who's this, Mickey Mantle or something, and he threw a pitch at my
crutch and I just shut my eyes and said a curse and swung and
slammed a hard grounder right down the line and under the legs of
the first baseman 20 some odd years before Bill Buckner got his
chance and I got a hit. I know it was kind of like that, because
this shaving wasn't the minimum three feet long as per the Rules
for the Contest to Become the King of the Neanderthals, so it
shouldn't qualify. But it still feels just as nice.

One more good thing is that in the process of taking this plane
iron from misshapen funkiness to terrifying sharpness I used up all
of about 25 cents worth of sandpaper, and probably about 3 cents
worth of spray glue, and about fifteen or so minutes of my time,
twenty if you stop for a nosehair count. When it was all done, I
peeled the sandpaper from the glass and threw it away -- well,
actually I could have but in truth I stick them together back-to-
back and save them in a "used-sandpaper" box for odd tasks that
never come up. I then scraped the little bit of residual adhesive
from the glass with a razor blade, a quick wipedown with acetone on
a piece of paper towel, and the cleanup was done in a minute. No
oil, no water, no mess, no glaze or flatness problems to worry
about, and a cutting edge that is Scary-Sharp (tm).

I think I'll still keep my stones, though; they can sit atop the
packets of sandpaper to help keep them flat.

-- Steve LaMantia [I'm talking about my oilstones.]
Seattle, WA

Mike Weaver

Nov 1, 1995, 3:00:00 AM11/1/95
On 1 Nov 1995, Stephen LaMantia wrote:


> Silicon carbide sandpaper (i.e., wet-or-dry) goes up to
> 600 grit in the hardware and woodworking stores, but up to 2000
> grit in the automotive finishing stores


Ok Steve, (and anyone else who cares to answer :-)

Where does one get this super-grit sandpaper?
(other than from a buddy who has some)

I've checked alt.answers, rec.answers, and the* hierarchy
for a FAQ that contains a mail order listing of companies that might
carry such great stuff, and haven't found squat.

Oh, I also checked the FAQ's from the metalworking group, but nothing
is obvious (nothing about abrasives or sandpaper for the companies

Michael P. Weaver Unix Systems Administrator Email:
University Computing Services, UMBC Phone: 410-455-2560
Baltimore, MD 21228 Fax: 410-455-1065
Disclaimer: The opinions expressed are mine, and not my employer's.

David Opincarne

Nov 2, 1995, 3:00:00 AM11/2/95
Oh. Considering the original aplication, maybe the back of some custom car
magazines may have some mail order places.

Ted Scott

Nov 2, 1995, 3:00:00 AM11/2/95
On 1 Nov 1995, Stephen LaMantia wrote:
> 2000 grit in the automotive finishing stores
Mike Weaver replied:

Ok Steve, (and anyone else who cares to answer :-)
Where does one get this super-grit sandpaper?

Mike, you get it in automotive finishing stores ;-)

That doesn't mean Manny Moe and Jack ;-) go to a *real*
auto parts house that sells automotive paints and supplies,
they will have a rack of it. Or try the Genuine Yellow
Pages under Automotive Supplies (New). Or just walk into
your local NAPA or Big A and ask. If you walk in and see
a spray gun, sander and body tool display it's a good sign.

BTW, There are lots of finishing stuff that can be borrowed from
the auto body industry. (After all they are just coachmakers who
no longer work much in wood.) The HD compressor opens up a world
of opportunity to use large panel sanders etc. If wood is to be
painted, use of automotive glazing compounds and even bondo can
be much easier than wood paste and yield superior results.


Joe Woerdeman

Nov 2, 1995, 3:00:00 AM11/2/95
Interesting timing. I was just at Japan Woodworker (800/537-7820) for those who
still don't have it) checking out their new stuff. They just started carrying some
new paper they've been trying out (3M I think). It comes in extremely smooth grits,
I'd guess it's close enough to 2000 grit (it was smoother than crocus cloth - what
is that stuff used for anyway). I have no idea what the pricing is on it, but they
are selling it. Apparently the grit is very uniform in size and came out of the
plastics industry where this sort of thing is important in getting polished finishes.


Mike Skorija

Nov 2, 1995, 3:00:00 AM11/2/95
Just go to any auto paint store in any city and you can get 1500 + grit sizes
They measure those items in microns, i think 5 micron is 1500

I also have ROS grits to 6000 for laquer, now thats a mail order item

Mike S

David Opincarne ( wrote:
: Oh. Considering the original aplication, maybe the back of some custom car

Richard Johnson

Nov 2, 1995, 3:00:00 AM11/2/95
In article <477j5j$>,

> I have a cheapie Radio Shack 30-power hand microscope

>-- "microscope" sounds impressive, but it's only $10,
> although I forget where I got it from -- and
I'll bet you got it from Radio Shack. :)

Nov 2, 1995, 3:00:00 AM11/2/95
(With all the snipping, I'm not sure who asked this question. Maybe Mike Weaver?)

> Where does one get this super-grit sandpaper?
> (other than from a buddy who has some)
I bought mine at the local discount auto parts center. They had plenty of it.

Stephen LaMantia

Nov 2, 1995, 3:00:00 AM11/2/95
Mike Weaver <> writes:

> Where does one get this super-grit sandpaper?
> (other than from a buddy who has some)

Hell if *I* know. That's the nice thing about having buddies. ;-)

Actually, according to David Opincarne, who sent me those 1200- and
2000-grit samples, you can get it from stores that supply auto-finishing
businesses, or from auto-supply stores that have a focus on auto finishing
and/or body work. He stressed that most run-of-the-mill auto supply
stores won't have it. The prices for this fine-grit stuff, he also
mentioned, is about the same as the more usual grits of wet-or-dry.


-- Steve LaMantia
Seattle, WA

Bruce Haugen

Nov 2, 1995, 3:00:00 AM11/2/95
At 09:03 PM 11/1/95 -0500, you wrote:
>On 1 Nov 1995, Stephen LaMantia wrote:
>> Silicon carbide sandpaper (i.e., wet-or-dry) goes up to
>> 600 grit in the hardware and woodworking stores, but up to 2000

>> grit in the automotive finishing stores

>Ok Steve, (and anyone else who cares to answer :-)
>Where does one get this super-grit sandpaper?
>(other than from a buddy who has some)
stop cruising the 'net and start calling your nearest auto body shop. I
checked with a local one and they carry all the wet or dry stuff you'd ever
want. All the way from 60 to 2000.


Stephen LaMantia

Nov 3, 1995, 3:00:00 AM11/3/95
to (Jeff Gorman) writes:

> Of course, this implies a sharp plane iron in the first place. There's
> a hole in my bucket, dear Liza, dear Liza ........................ 8-)

Reminds me of a constant source of confusion for me when starting out,
instructions like:

"To cut a board straight, guide your saw with a straight board..."

Stephen LaMantia

Nov 5, 1995, 3:00:00 AM11/5/95
Joe Woerdeman wrote:

And Mike Weaver responded:

> Very interesting timing indeed. I was looking at the Japan Woodworker's
> catalog just yesterday, and saw that stuff.

> EXPENSIVE! They sell it either as just a paper-like substance that has
> a self-stick adhesive on the back (for about $40 for a piece 8" x 2"),
> or something like $60+ for the same grit already mounted on an
> aluminum block.

Just looking at that catalog now. It comes in grits 200, 400, 800, and
1800. (Looking at the associated micron particle sizes (74, 40, 20, and 10
respectively), it looks like the U.S. grit numbering system for stones
and sandpaper.)

The flexible stuff, with pressure-sensitive adhesive (PSA) backing, comes
in two sizes, 8" x 3" and 6" x 2". Japan Woodworker's catalog lists:

microns grit 6x2 8x3
------- ---- ------- -------
74 200 $ 26.55 $ 51.85
40 400 21.60 42.45
20 800 21.60 42.45
10 1800 21.60 42.45

Yes, that's expensive.

> What I found really interesting was their claim that 'the flexible
> backing makes these really great for sharpening japanese chisels'
> (paraphrased there).

> Why? I don't understand why you'd want *any* flex in the sharpening
> material.

Here's what the JWW catalog says about the aluminum-plate stuff:

3M diamond stones are micron graded to provide a consistent
finish. Micron abrasives are more closely graded than other
abrasives. This means that there are no individual particles
to leave deep scratches in your finished edge. For durability
and longevity, the diamond abrasive is nickel plated to a
flexible backing in a precise dot pattern which gives a superior
finish in less time. This diamond backing is then laminated to
a 3/8" aluminum plate, guaranteed to be flat. Because of the
flexible backing, 3M diamond stones are suitable for sharpening
all Japanese tools. They are offered in 4 particle sizes to
give a complete range of cutting speed and finish and are color
coated [yes, "coated", not "coded" -- Steve] so that particle
size can be easily determined.

So at least according to the catalog write-up, there is supposedly
something about a backing that flexes that makes them suitable for
Japanese tools. I'm as ignorant as to what this means as you are, Mike.
Likewise, is seems counter to what we'd want in an abrasive surface,
namely flatness, not flexing. Maybe if Dave Burnard, who uses Japanese
tools, is reading this, you could enlighten us, Dave?

I don't know about the aluminum-mounted stuff, but as for the unmounted
flexible PSA stuff, I guess I could see where it'd be uniquely handy. You
could make up a special-shape mounting surface to stick this stuff to --
the most obvious example, I guess, would be to a dowel to hone gouges --
and because it's diamond you'd have a reasonably permanent specialized
sharpening "stick" for that tool.

> Anyway, I think the $5 for 5 sheets of 2000 grit locally is a much
> lower price to experiment with.

I'd agree.

> (hey, I actually checked the Yellow Pages, can you believe it? :-)

"Yes, even *you* can ..." :-) Just learning to do that myself lately.

Of more immediate interest to me at the moment is another product by 3M,
called "Micro-Finishing Abrasives". I'll be posting more on this stuff
later, but for now imagine a sandpaper that goes up to 9000 grit (or
16000, depending on where you read about it, but the general concensus
is that particle size is 0.5 micron), has a cutting agressiveness that is
faster than a stone five times as coarse, has extreme regularity of grit
size, comes on a Mylar backing (i.e., very flat), and can be had for
about $2 a sheet.

For your homework, see pgs. 56 and 57 of Leonard Lee's book _Sharpening_,
and pg. 38 of the 1994/95 Lee Valley catalog. Over and out. :-)

Brent Beach

Nov 6, 1995, 3:00:00 AM11/6/95

On Thu Nov 2, (Jeff Gorman) wrote:
>In message <477j5j$> Stephen LaMantia wrote:
>~ I ended up getting a shaving that was so darn thin I could read
>~ newsprint through it easily.
>Perhaps this is also a tribute to the flatness (or the convexity) of
>the sole of your plane 8-). If it were concave or had a bump behind
>the mouth (as can happen) this quality of shaving would be hard to achieve.

Just bought a new Stanley 5 1/2 for $49 Canadian: seemed like
too good a deal to pass up. Sharpened it up and tried it out:
no matter how sharp the blade was, it would not leave a smooth
surface. Finally checked the flatness of the sole and sure
enough, the area immediately behind the mouth was high and was
acting as a second, very blunt blade.

Not the dreaded "truing the sole" thread again. Sorry, it is.

I started out with 180 grit silicon carbide on plate glass, but
it was very slow going.

I had also just gotten a 1" by 30" 'Sharpening belt - Blue
Zirconia' from Lee Valley, 120 grit ($2.40 CDN) and had tried
it for sharpening my wood turing tools. I normally use 320 grit
aluminum oxide. The Zirconia was much too agressive: it is as
fast as, or perhaps faster than, an aluminun oxide wheel on a
grinder. It is better than a grinder though, since it leaves
the metal very cool. So, no good for sharpening but good for

So, I cut it into 5" sections and taped then parallel, but
about 1/2" apart on a sheet of glass and lapped the sole of the
plane. Took just a couple of minutes to remove the bump. After
the zirconia, smoothed it a bit with 180 grit silicon carbide.
The sole is now things flat enough to get the "read type
through the shaving" thinness of shaving and smooth work. Since
the blue Zirconia is "designed to grind hardened steels of all
kinds" it has absolutely no problem with cast iron.

So, people who use 1" sanders for sharpening can also use them
for grinding. Perhaps Lee Valley will add much finer grits in
this material for sharpening and honing, in addition to
grinding. BTW, it is a Klingspor brand sanding belt: they may
supply finer grits directly.

Brent Beach, Victoria, BC

Mike Weaver

Nov 6, 1995, 3:00:00 AM11/6/95
Stephen LaMantia wrote:
>> Silicon carbide sandpaper.... up to 2000 grit....

I wrote:
> Where does one get this super-grit sandpaper?
> I've checked alt.answers, rec.answers, and the* hierarchy
> for a FAQ that contains a mail order listing of companies that might
> carry such great stuff, and haven't found squat.

Well, after a couple of helpful, humorous (and somewhat humiliating :-)
replies, I took a look through the Woodworker's Supply catalog, and
whaddya know?

They've got silicon carbide sandpaper up to 2000 grit right there. And,
it's much cheaper than retail. Most of the finer grits are $4.50 for 10
sheets, but if you buy a least 5 sleeves (10 sheets each), the price
goes down to $3.20 for 10 sheets.

Yes, these are 8.5" x 11". And, no, I have no clue why they call a pack
of 10 sheets a 'sleeve'. :-)

I just ordered a bunch...

Well, Steve I'll let you know how the sharpening experiment here
on the east coast works out. WHo knows, maybe the air is different :^)

Thanks for the replies,

Thomas Dalzell

Nov 16, 1995, 3:00:00 AM11/16/95
In article <47irm9$> (Stephen LaMantia) writes:
>From: (Stephen LaMantia)
>Subject: Re: Sandpaper Sharpening
>Date: 5 Nov 1995 17:19:05 GMT

>Joe Woerdeman wrote:

I don't see why you would want flexible stones for bench chisels, but JW sells
a fairly wide range of Jap. gouges too, and you can stick the stuff to custom
wood backers for these, rather than power sharpening which is likely to alter
temper if you have a heavy hand.


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