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265056 Thomas Conroy 2018‑02‑08 Leather paring and knives, was: Strop
Brent Beach asked for "A bit further explanation, please." I'm going to break my
reply up by his questions. It gets long, I'm afraid.


"What kind of a knife are you using here - what shape, length, bevel angles?"
      I work normally with an English paring knife for beveling the edges of
leather for a cover (on the inside), and with a modified spokeshave for overall
thinning of the leather. The English paring knife is pretty much like a
cabinetmaker's skew chisel, but less than 1/16" thick overall, perhaps 1-1/8"
wide (give or take a bit), and often made without a handle. Mostly I use knives
made by Barnsley before they closed
http:/
/www.hewitonline.com/English_Paring_Knife_p/tl-070-pk.htm

 but Hewit found another firm that copies the Barnsley knives almost exactly. I
normally hone to roughly 18 degrees (1 rise to 3 run), but Jeff Peachey who
makes boutique binders' equipment normally hones to, if I remember correctly, 15
degrees, perhaps less. I grind back the primary every once or twice I hone.
Barnsley knives are surprisingly soft, perhaps as low as Rc54, but this means
that they are also comparatively easy to resharpen, and I like the trade-off.
Jeff Peachey goes in the modern direction of exceedingly hard steel, which most
amateur binders love because they have never before used a sharp knife and it
holds its edge, but the hard steel is correspondingly dreary to sharpen and
tempts you into trying to work for too long with a dull blade. My opinion that
leather takes off an edge quickly is not based on the soft Barnsley knives
alone, by the way, but more on spokeshave blades where I have a direct
comparison between use on wood and use on leather.      A 151-style spokeshave
can be used for leather out of the box, but many (most?) experienced binders
lower the bedding angle from 45 degrees to as little as 31 degrees, open the
mouth out to allow leather shavings to pass through easily without clogging, and
there are various other tuning points, some of which also apply to spokeshaves
for wood. For leather the blade should be honed to, again, 15 or 18 degrees at
most, and this means that the ground bevel must be wide. I hollow-grind my
Stanley/Record blades with a bevel 1/4" wide, on Hock I grind 3/8" wide due to
the extra thickness of the blade. I was taught to keep and sharpen blades in
batches, so that when a blade goes dull halfway through paring a cover you can
go on working with a fresh blade without completely changing gears for
resharpening. For years I used Stanley and Record blades (bought early in my
career) at work, and my good Hock blades at home; when it finally got through to
me that this was backwards I changed and used just the Hock blades at work. With
the chrome-vanadium Stanley/Record I generally had half-a-dozen in my working
batch, but with Hock I found that three was enough. For Barnsley paring knives I
kept four to six going at any one time, with a few older and better knives for
special use.
      I also have a little knowledge of the Scharfix and similar paring
"machines" (they are more like big jigs) which offer some less-subjective
evidence on how quickly leather dulls an edge.

https://www.youtube.com/wa
tch?v=_c8hIzkJlAs

These come with special blades, but are normally used with double-edged razor
blades, which are normally discarded after taking off two or three strips of
leather, say about 40" total length. I know one highly skilled binding teacher
who buys her razor blades by the thousand-blade box, because that lets her get
the top quality blade of her preference. You can buy special blades for the
Scharfix that come sharp, but they cost about 40 cents each. A Scharfix appeals
to many binders because it seems to reduce the amount of skill needed for paring
leather (it doesn't really, but that is another matter), but the big draw is
that you don't have to do any sharpening at all. And a Scharfix comes with a big
price tag, for the machine (about $400.00 new) and for blades.
      There are other tools used by German, French, and other style binders, but
the principles are the same. The shoe industry uses genuine (powered) tubular-
bladed paring machines, and these have a built-in grinding wheel for
resharpening, in some brands running in constant contact with the blade.


"How exactly do you strop the knife? How do you hold it? How many strokes on the
rouge?"
     I normally start with the rouge (hardware store stick) charged on flesh-
side leather glued to a flat board held flat on the bench; I stroke five times
on the flat followed by five on the bevel, being careful not to pull up and
round the bevel on the turn; repeat five; then three on each side repeated; then
one each two or three times. Then repeat on uncharged grain-side leather. It
sounds like a lot, but it actually takes very little time (OK, I shortcut it a
lot of the time, strop a third or half that much on many stroppings), and I am
normally thinking what to do next while I do it. The big danger is allowing the
blade to drift up at the end of the stroke, rounding the edge, and this danger
becomes acute when you go from stropping the flat to stropping the bevel. The
danger of rounding can be reduced by turning the blade over "over the back,"
lifting the edge first from the surface, rather than over the edge in the
instinctive manner, and this is what I teach; but I learned about the technique
too late to work it into my habits. Stropping on the uncharged grain size does
make a perceptible difference in the ease of use of the knife; after rouge alone
the knife may be usable, but it will be cranky and intractable, not sweet-
cutting.      The bevel side of the spokeshave can be stropped without
disturbing the setting by pulling it backwards toward you over the strop, and I
used to do this with Stanley/Record blades, but I don't bother with Hock blades.
The problem with stropping the spokeshave is that taking the blade out disturbs
the setting, and once you have it out you might as well do a thorough job of
sharpening. So blades must be sharpened frequently when over-all thinning
leather, no way around it. Leather of different colors (i.e. different pigments
or dyes) differ in how abrasive they are to the blade, but with most black
leathers and with alum-tawed skin (whitleather, i.e. white, to the Elizabethans)
a spokeshave blade may go dull while thinning a single 12" x 18" piece for one
cover.
 

"What is the paring action? What does 10-25 inches of paring mean?"
      Edging with the knife bevels the leather down from the full thickness as
supplied down to nothing, over about 3/4". The edge moves directly into the
skin, removing a strip the full length of the edge. The skew bevel is necessary
to allow the knife to cut; if you try paring with the knife edge at right angles
to the leather edge, it will hang up and refuse to cut, no matter how sharp it
is.  Here is the video of Jeff Peachey doing a nice job of paring an edge,
already linked to above:
https://www.youtube.com/wa
tch?v=QB5ZHNdqTPQ


Jeff is apparently paring with the tip of the knife along the left edge of the
cover as it rests in front of him (one of the legitimate choices, but possibly
the filming angle is deceptive and he is paring left-to-right on the far edge).
Notice the ease and evenness of the stroke, and that the strips of leather come
off intact, and that he gets an even bevel about 3/4" wide with just the knife.
Taking the three strips off gives a rounded shape to the pared area; a single
sharp arris would leave a visible ridge on the outside after the leather is put
on. Further blending of the slope can be done with the spokeshave. I was taught
to edgepare with the heel of the knife-edge on the right side of the cover,
pushing away from myself; I still teach this way, since there is a conceptual
clarity about controlling the angles when paring with the heel (picking up the
terms pitch, roll, and yaw from aviation). In practice I usually pare with the
tip from left to right along the far edge of the leather, which I think is
easier once you have the conceptual understanding of the ways the edge can tilt.
      I found another video, however, that is rather more instructive than the
one of Jeff paring, since the guy who made it is not highly skilled with the
knife (the actual demonstration of paring, as opposed to hot air, runs from 2:08
to 4:50):

https://www.youtube.com/wa
tch?v=GKQNVC_l0OQ
He does OK on the first strip, certainly at first, but notice that he has the
forefinger of his left hand on the blade. This means that he is pushing the
knife to get it to move at steady speed and angle, and this means that the knife
is not quite sharp. Sharp enough to work with at a pinch, but not sweet, not
sharp enough to use with ease or pleasure. Things go to pieces on the second
stroke, where he is taking off the arris left by the first stroke; from the
beginning it is fluffy-edged and narrower than the first strip (notice that each
of Jeff's strips was wider than the last, and precise). Within four inches of
the start of his stroke, the leather removed is breaking up into dust; and as he
goes on, an educated eye can see that his edge wobbles up and down, leaving
something akin to a chatter on a large scale. I think he is using an old
Barnsley knife, and he didn't strop it between strokes. Things really go to
pieces at the end, where he is trying to thin and clean up the corner of the
leather; by this time the knife is so dull that it will barely cut, and will
only scrape a bit of dust off with each stroke.      I said this guy is not
highly skilled with the knife; well, in fairness, he is probably more skilled
than eighty or ninety per cent of bookbinders. And he does seem to be a
professional. He does a nice enough job of demonstrating round bible corners in
leather at the end of the video. But he doesn't pare well, and it is because he
doesn't know how to strop----in what I called the "hot air" part of the video,
and he makes stropping moves with his hand around 1:10-1:12; these show that he
habitually rounds the edge while stropping, dulling the knife. You can work
around poor skills, but it ain't fun.

One more video is useful in showing how not to do things:
https://www.youtube.com/wa
tch?v=qK6hb7pcjcU

This guy is a general leatherworker, and I'm not going to judge his skill at his
own craft and by comparison with others of his kind. But he doesn't know how to
sharpen and he doesn't know how to pare ("skive" to saddlers and other heavy-
leather craftsmen). Notice that he uses a sawing back-and-forth action. Instead
of pushing one section of the edge along the leather, he runs repeatedly from
the tip of the knife to the heel. This is a classic way of getting a dull knife
to cut in some degree; the problem with it is that you have little control, and
it takes far longer than it should. In fairness again, he is working on salvaged
leather that is probably thicker and harder than binding leather, andd he may be
fighting glue residues and old thread in the visible sewing holes. As with the
previous guy's failure to strop, you can get a knife to work this way, sort of.
      Since paring isn't the only thing you do in binding, you can be a very
good binder and not have good paring skills. Laura Young, one of the most
successful book restorers and binding teachers of the generation before mine,
never learned to sharpen or pare, as shown by her frequently republished manual
on binding (and I have had her deficiency confirmed by a number of my friends,
many of whom were her students). Young described the sawing -action type of
paring for occasions when a knife couldn't be avoided, but her basic advice was
to get a Fortuna skiver, a heavy-duty industrial machine that costs (now)
$1500.00 new and sprays grinding swarf over the freshly-pared area (this doesn't
matter in a shoe that will be trash in a year, but does matter as the life of a
book stretches from the decades to the centuries). So you can be a very good
bookbinder indeed without being able to pare skillfully When I entered the
field, many San Francisco fine binders would send their leather to France to be
pared professionally, much as San Francisco miners of the Gold Rush would send
their laundry to China. I still think you ought to be able to do your own work,
and do it well.

OK, I'm exhausted, and if you aren't as well, I'm surprised. My vile antiquated
PC with vile Microsoft hardware and vile Yahoo that I chose for my email many
years ago are between them crashing about every forty minutes, which means that
I've spent a good many hours on this. Lord, return me safely to Apple, with up-
to-date software. Brent, many thanks for asking such clear and well-organized
questions, which have made it much easier for me to answer with (I hope) a
degree of clarity and organization.

Tom ConroyBerkeley
265059 Claudio DeLorenzi <claudio@d...> 2018‑02‑08 Re: Leather paring and knives, was: Strop
Hi Tom:
Re the knife used in these videos reminds me of the ones my dad used in
upholstery.  He copied an old Osborne one, making his own from discarded
Swedish steel metal cutting saw blades from a metal shop (I’m pretty sure
these were high carbon steel, not high speed steel).  These metal cutting
blades were about 1.5” by 24” and maybe 1/16”  thick and he would cut off a
length,  grind off the teeth and then make similar single bevel knives like
those shown in the video.  Watching these videos brought back memories of
him showing me how to work leather, button tuft diamond patterns, turn
corners...

  My dad taught me another important lesson: That you can learn something
useful from just about anybody if you are open to it and treat them with
respect, even a janitor (nothing against janitors, my mom was a cleaning
lady).
  Speaking of which, I just remembered the first time I chatted with the
janitor at the metal factory when I was a young dumb teen in a summer job.
  I innocently asked the old Polish man about the greenish colored numbers
tattooed on his forearm.  I didn’t really know anything about concentration
camps at the time.
Claudio
265070 Chuck Taylor 2018‑02‑08 Re: Leather paring and knives, was: Strop
==snip==
Brent Beach asked for "A bit further explanation, please." I'm going to break my
reply up by his questions. It gets long, I'm afraid.
==unsnip==


Tom,

Thank you for taking the time to describe so clearly your experience with
sharpening and using knives for paring leather. From your description of working
with leather, wood seems to be a much more forgiving material than leather. With
wood we can sometimes compensate for a not-quite-sharp edge with a bit of brute
force. Apparently that doesn't work so well with leather.

I'm reminded of the words of that great philosopher Yogi Berra (American
baseball player of yore, Jeff): "In theory, there is no difference between
theory and practice. In practice, there is."

Chuck Taylor
north of Seattle
265071 "John M Johnston (jmjhnstn)" <jmjhnstn@m...> 2018‑02‑08 Re: Leather paring and knives, was: Strop
See also the immortal Sir Boyle Roach, who like Yogi Berra was also known for
enlightening quotes.
https://en.m.wikiquote.org
/wiki/Boyle_Roche

https://h2g2.com/edited_entry/A6
73607

Cheers
John
“P.S. If you do not receive this, of course it must have been miscarried;
therefore I beg you to write and let me know.” - Sir Boyle Roche, M.P.

I'm reminded of the words of that great philosopher Yogi Berra (American
baseball player of yore, Jeff): "In theory, there is no difference between
theory and practice. In practice, there is."
Chuck Taylor
265072 Kirk Eppler <eppler.kirk@g...> 2018‑02‑08 Re: Leather paring and knives, was: Strop
On Thu, Feb 8, 2018 at 5:27 AM, Thomas Conroy via OldTools <
oldtools@s...> wrote:

>  Here is the video of Jeff Peachey doing a nice job of paring an edge,
> already linked to above:
> > https://www.youtube.co
m/watch?v=QB5ZHNdqTPQ
>
>
And just for everyone's information, this is why all of the BAGS stand back
in fear whenever Tom brings out one of his leather blades.

There's Scary Sharp, and then there is Bookbinder Sharp, which is somewhere
beyond Terrifying Sharp.

My best sharpening work pales in comparison.

-- 
Kirk Eppler in Half Moon Bay, CA, working with a new foster dog last night.
265073 Claudio DeLorenzi <claudio@d...> 2018‑02‑08 Re: Leather paring and knives, was: Strop
My fav YB:  “I looked like this when I was young, and I still do.”
C

On Thu, Feb 8, 2018 at 12:54 PM Chuck Taylor via OldTools <
oldtools@s...> wrote:
265084 rock harris <nombre7@g...> 2018‑02‑10 Re: Leather paring and knives, was: Strop
*From your description of working with leather, wood seems to be a much
more forgiving material than leather.*

As a burgeoning leatherworker/leathercrafter, I can attest to this. My
skills at sharpening are helping me greatly with sharpening leather knives.
The only thing giving me fits because I haven't come upon a good process is
sharpening my head knife. (a half moon knife that is emblematic of the
leatherworking profession).

I thought woodworking meant a lot of sharpening, then I started making
leather objects. Woof. I can see why razor blades used by the hundreds is
standard among hobbyists like me.

rock harris
lesser programming deity, budding dilettante furnituremaker, analog
photographer, and aficionado of obsolete machinery
st. louis, mo
314.221.5941

Yeah, well, you know, that's just, like, your opinion, man.

On Thu, Feb 8, 2018 at 11:52 AM, Chuck Taylor via OldTools <
oldtools@s...> wrote:
265085 Thomas Conroy 2018‑02‑10 Re: Leather paring and knives, was: Strop
Rock Harris wrote: "The only thing giving me fits because I haven't come upon a
good process is sharpening my head knife. (a half moon knife that is emblematic
of the leatherworking profession). I thought woodworking meant a lot of
sharpening, then I started making leather objects. Woof. I can see why razor
blades used by the hundreds is standard among hobbyists like me."

Get a copy of "Leathercraft Tools: *How to Use Them *How to Sharpen Them." by Al
Stohlman. This gets across far more of the basics of leather tools than any
other source I know. It is a kind of book that normally drives me to agonies of
contempt, lots and lots of pictures and comparatively little text. But Stohlman
had the touch, he is concise in his pictures and concise in his text and
everything needed is there (I think, a memory of the first times I used the
book) and it is all correct (ditto). In the same category, as an absolute
essential, is his "The Art of Hand Sewing Leather." I think I had learned most
of what he has in the book before I discovered Stohlman, a fact or two at a time
from a dozen different books, none of which had more to offer than that one
isolated fact. But Stohlman gives a whole.

Most of Stohlman's other books are "project" books, and I could care less.
Project books have always bored me and struck me as unnecessary. And Stohlman's
biggest focus was on Western-style leather carving and, well, lets just say he
wasn't Frederick Remington. But on basic leatherworking technique he is
unmatched. No one else can even be compared.

Leatherworking has suffered from a two-angle learning slope. It is very easy to
learn how to do some simple basic things, and have a bit of fun for a while. But
to go from those simple things to work that is really rewarding for a long
period, the level of technique to be learned is staggering. Leather is one of
the most versatile and profound materials, but it demands high skill to get the
best out of it, or even to advance beyond laced-edge keyholders.  The difficulty
in learning to sharpen a head knife is sort of emblematic of the difficulties,
in a way, just as the knife itself is (as you say) emblematic of the whole
craft. In America in the last century the craft went through cycles of
popularity, and with each cycle there was a generation of "teachers" who had
never tackled the second, steeper, slope, and each generation knew less and less
technique. By now, it is hard to recover the lost skills. Compare the horribly
crude work of a storefront sandlemaker of the 1970s with some of the sixty-to-
the-inch stitching on English riding boots of the nineteenth century, shown in
John Waterer's Leather Craftsmanship (New York: Praeger, 1968), the best
introduction I know to the deep possibilities of leather.

Waterer writing in the 1960s said that saddlers had preserved more of the heavy-
leather skills than anyone else, and bookbinders more of the light-leather
skills. That still looks pretty much true to me (though skilled bookbinding is
under assault from weekend-workshop "book artists"). I suspect that skilled
saddlery will survive as long as there are saddles at all. After all, if a
saddler isn't skilled, a horse gets a sore back. No arguing with that, no real
way to say "I like it better that way," and a great big financial hit if you
have to throw a saddle away and try to make a better one.

Tom Conroy(not a real leatherworker, not for heavy leather, but at least a
little way up that second, steeper, slope).
265096 rock harris <nombre7@g...> 2018‑02‑11 Re: Leather paring and knives, was: Strop
Yeah, I have many of Stohlmann's books, but not the tool book. I'll look
into it.

I've been working on my stitching, and I'm making a stitching horse to help
(two actually, and keeping on list topic, I'm using a lot of hand tools to
make it).

Leatherworking is a lot like woodworking in the tool department. Unique and
really really cool.

I get what you say about the basics versus the true art. But I got time.
And it's fun....


rock harris
lesser programming deity, budding dilettante furnituremaker, analog
photographer, and aficionado of obsolete machinery
st. louis, mo
314.221.5941

Yeah, well, you know, that's just, like, your opinion, man.

On Sat, Feb 10, 2018 at 1:05 PM, Thomas Conroy 
wrote:
265121 Thomas Conroy 2018‑02‑13 Re: Leather paring and knives, was: Strop
Claudio wrote:  "Re the knife used in these videos reminds me of the ones my dad
used in upholstery.  He copied an old Osborne one, making his own from discarded
Swedish steel metal cutting saw blades from a metal shop (I’m pretty sure these
were high carbon steel, not high speed steel).  These metal cutting blades were
about 1.5” by 24” and maybe 1/16”  thick and he would cut off a length,  grind
off the teeth and then make similar single bevel knives like those shown in the
video.  Watching these videos brought back memories of him showing me how to
work leather, button tuft diamond patterns, turn corners..."

Machine hacksaw blades were particularly favored paring knives and lifting*
knives by the generation of English binders who taught many of my generation of
Americans. They were mostly born around 1935 and trained in seven-year
apprenticeships or in comparably rigorous art school courses. The preference was
not just for machine hacksaw blades, but "pre-war" blades, which were said to
take a sharper edge and hold it longer than any other form of knife. I suspect
that they were finding high-carbon-steel blades, though these would have been
obsolescent in America by the 1930s.

Until quite recently lifting knives couldn't be bought; you had to grind your
own. I've made them, for myself and for half-a-dozen or a dozen students, from
old trashed hacksaw blades (25 cents with luck, but more often a dollar now);
from new Vaughan English "all-hard" or "high speed steel" hacksaw blades (the
markings differ, but they seem to be otherwise just the same); and from new
Starrett "Red Stripe" HSS blades. The first step is to snap the (12" or 14"
long) blade in half, and with an old hacksaw this will tell you if you have a
good single-steel blade or an unusable bimetallic blade. The good blade will
snap cleanly with a fine-grained crystal surface on the break; a bimetallic
blade will snap cleanly in the eight inch near the teeth, but the rest of the
width will twist and deform before breaking. My favorites are the old blades,
but this may be partly sentiment. The Vaughan blades are good, a bit hard; the
Starrett far, far too hard for this use, since it is extremely tedious to
resharpen them. Lifting the leather on the side of the book, you are cutting
through highly-abrasive binders' board, full of trash and impurities, and you
may lose the sharpness of the edge in lifting four inches; so you go through
three blades lifting on one board. Not to speak of 19th-century board, when it
was sold by weight and some manufacturers would throw sand into the pulp to
increase the weight. Fortunately, a highly refined edge isn't necessary for
lifting; a slightly saw-edged knife works as well or better than the most highly
polished, so I do touch-ups while lifting on the coarse side of a "punjab" razor
hone, equivalent to maybe a soft arkansas or an 800-grit (or coarser) water
stone.

_________________________________________________
*Lifting: in conventional reattachment of boards, the covering cloth or leather
is raised from the board along the spine edge, then the new leather is slipped
in under the flap that has been created. The same is done on the inside, for the
endpapers. There are several techniques for partly detaching the covering,
depending on the leather or paper, the board, and on how good the attachment is.
On most books at least one side of the board will have to be lifted with the
knife, which is similar to a paring knife but skewed opposite and with a smaller
skew angle. This is used to cut between the leather and board, or better,
through the board itself leaving a paper-thin layer of board still on the
leather. Any lumpiness in the cut will be seen when the work is done. And
everything you are trying to cut is crumbly.
Want some idea of how hard this is on a knife's edge, and how hard period? Take
a short 1-1/4" chisel and try to bevel the edge of a piece of eight-inch thick
cardboard with it, making the bevel an inch wide and running down to a feather
edge. Do it without going over any spot twice. And consider that to lift the
leather on an ordinary-sized book, you will need to make an even surface three
inches (not one inch) wide and nine inches long. I couldn't find any videos of
doing it; my guess is that it is too hard for the sort of binder who makes
videos, and they don't want to show the botch-up they make of it. But maybe I'm
just a cynic.
And don't even get me started on lifting an old spine that is adhered directly
to the book. I did find at least one video of this, but it was being botched, so
I averted my eyes.
Tom Conroy.
(Just let me ramble on a few more hours, eventually I will go to sleep and you
can escape)

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