A Knife From The Hood

birck-ft

birck

At first, I thought the above knife was a German style paring knife, but now I’m not so sure. German knives are almost always somewhat flexiable, and this one is very rigid.   Notice the small recess on the handle, near the blade, perhaps worn by fingers gripping the handle over the decades.  Even a light surface cleaning could destroy not only important use evidence, but the overall beauty of the knife.  As I have said before, the over-cleaning and “restoration” of  hand tools is perhaps the most significant ongoing loss of cultural property  that commonly occurs.   The blade is full tang and has a gradual taper in thickness towards the cutting edge. Judging from the scratch patterns in the top picture, the owner must have had a stressful encounter with his grinding wheel!  But I find these marks interesting evidence of the history of the tool, as well as a visually refreshing antidote to the ubiquitous monotony of the highly regulated machine grind marks found on new tools.  The handle is an unidentified light colored wood that has been stained and is still firmly attached to the tang. The edges of the handle is still quite sharp, and the various ways I have tried to hold it all are somewhat uncomfortable.

Matt Murphy  found some information about Fred J. Birck:  “From 1903-04 he worked at 93 Essex St. In 1905-06, Fred. J. Birck is listed as being a part of Birck & Zamminer Cutlery, which is located at 154 Essex St.  In 1908-1912, Birck is listed at two seperate addresses, 132 Essex St. and 17 Cooper Sq. East. In 1912-1913, the primary address is changed to 17 Cooper Sq. E.  In 1913-1914, the partnership must have been dissolved, because only Birck is listed, and the only address is 17 Cooper Sq. E. until 1925.  Also, Mr. Birck made his home in Jersey City, New Jersey, as his address is often listed as 144 Hutton St. (Which still stands to this day.)”

So the knife is possibly from 1913-25.  Aside from the beautiful, insanely deep makers mark, I was attracted to the fact that another knife-maker worked in the East Village of NYC, only about 5 blocks from where my studio is now. There is even an old bar,  McSorley’s, established in 1854, still operating right around the corner from Birck’s 17 Cooper Sq. address. Perhaps Birck had a drink there.  I’ll raise a glass to him next time I’m there.

 

Don Rash posted a similar looking knife on his blog, unfortunately no makers mark.  I looked through Salaman’s Dictionary of Leather-working Tools c. 1700-1950 and couldn’t find any similar knives, and Salaman covers some pretty obscure leather-working trades ( ie. gut string maker, hydraulic pump-leather maker) but tends contain more English rather than American references.

 

Below is the German knife from Zaehnsdorf’s The Art of Bookbinding, 6th Ed. 1903. It almost looks like the knife is shaded more heavily on the top edge, to make clear the blade tapers toward the other edge?

german-paring-knife

Cobbler’s Bones

 

bones

    Hirth & Krause, Dealers in…Leather and Findings. Shoe Store Supplies, etc. Grand Rapids, MI: 1890.( p. 46) 

Kevin Driedger , who writes the interesting Library Preservation blog, posted a useful comment a couple of months ago, wondering if I was making an erroneous assumption about how a Turkish bone was used.  I guessed it was used for marking.  Lately while reading a old supply catalogue for the shoemakers I realized it that shoemakers have two distinct types of bones, termed scratch bones and slick bones.  Now I’m convinced that the Turkish cobbler’s bone I wrote about is a scratch bone.  Turkish shoemakers now make European style shoes, not Ottoman.

Judging from the catalog descriptions, it seems the scratch bones (similar to a scratch awl?) were used for marking, and slick bone was used for burnishing or smoothing.  I wonder if the right angles on the left end were also used to scratch a line?  This shape, seems to have served as the template for the most common shape that bookbinders use, with one flat and one rounded or pointed end.

Below is a slick bone that I purchased with some other shoemakers tools.  It is thicker than most of the cow bone folders that are commercially available to now, and has a pleasing natural shape.  The facets of the somewhat crude shape are highly burnished, suggesting it was used with a far amount of force or speed, the accumulation of glue residue and deep scratches give it a gorgeous patina from use.

cobblers-bone

Observations on Blade Angles of English Style Leather Paring Knives

“One of the most admired skills in bookbinding is the paring of leather, yet only sharp tools and confidence are required.  Confidence is gained by experience, and sharp tools by a zelous consideration and care for knives.” Arthur Johnson, The Thames and Hudson Manuel of Bookbinding, p. 89

I would add that it is also critical to pay attention to the blade angle of the knife, since it affects how the knife cuts, the angle one holds the knife at, and consequently how the leather is cut.  I’ve found that roughly a 40-50 degree angle works best for edge paring.  First, a few terms defined.  The blade angle is from an imaginary line 90 degrees to the length of the blade.  I am calling a zero degree angle one that would be straight across where the dotted line is, pictured below would be roughly a 45 degree blade angle.  The bevel angle is the amount of slope on the bevel, in the case of leather paring knives usually around 13 degrees.  The diagram below is the style of knife a right handed binder would normally use. (1)

 

I’ve found there are two main issues that determine the optimal angle of the blade– how much the blade is skewed in use and how the knife is held.  The way I hold and use an English paring style knife is outlined below, as are the reasons why I consider a 40-50 degree blade angle ideal.  

Skewing the blade in use reduces the effective cutting angle, improving the initial cutting performance and not altering edge retention.  Although the more acute the bevel angle is the sharper the blade will be, if it is too severe the cutting edge will be very fragile and quickly deteriorate.  I haven’t figured out the math, but if the bevel angle is 13 degrees, I estimate an extreme skew reduces the effective cutting angle by a degree or two, which is significant.  

I tend to use an English style paring knife in three ways when I am edge paring- first to make a series of cuts using moderate skew, then a few finishing cuts using extreme skew, and finally use the knife with no skew, almost like a spokeshave, to smooth everything out. It doesn’t seem to make too much difference if you pare across the skin, as pictured above, or push the knife away from you.

To make a long, even bevel the angle of the knife held steady by my thumb and second finger on the other side of the the knife– they slide along the surface of the paring surface. In order to pare the leather evenly, the knife must be held at a consistent angle. (2) The angle the knife is held varies with the type of leather and skill of the binder- too high of an angle takes off virtually no leather, makes it more likely to slice through the flesh side of the skin and dulls the knife tip by digging into the paring surface.  Too low an angle makes the knife difficult to control, since most of the cutting edge is engaged into the leather.  Wide knives with long bevels exaggerate this problem.  Right handed beginning parers may want to use the forefinger of left hand to push the knife along the leather.  This allows one to concentrate on using the right hand to hold the knife at a consistent angle, as illustrated below.

One reason I dislike jigs for sharpening is that the hand skills to sharpen the knife are remarkable similar to the hand skills necessary to operate the knife– if you don’t have the hand skills to hold the knife at a consistant angle to sharpen it, you are not going to be able to hold it at a consistant angle to pare leather evenly.   Some like to pare across the leather, as illustrated below, and some like to pare up the side of the leather, starting the cut with the heel of the knife rather than the tip. Since lithographic stones are now extinct, I prefer paring on a piece of glass and saving stones for printers wishing to experience printing on a real stone.  There is no reason to pare on a litho stone other than tradition, and I suspect the only reason they were historically used is that they were a cheaper flat surface than glass, marble or granite

 

 

 

 

 

 

 

 

 

 

 

 

After a first cut is made, a second (and possibly third or fourth, depending on how long of a bevel is desired) is made by holding the knife at progressively  lower angles.  The depth of the cut can be judged by changes in the color of the leather or folding the leather in half, which doubles any errors.    If the leather is disturbed to check the progress, it is imperative that any stray bits be cleaned from under the skin, otherwise the knife will cut through these thicker layers.

As the leather becomes thinner, it becomes weaker, so I adopt the second knife position.  I skew the knife towards a more extreme angle and press down harder, which creates a lower effective bevel angle. This helps prevent tearing the leather.  It is much easier to take the leather off in long even strips with the first cuts, rather than try to correct mistakes later on.  If there are many irregularities, sometimes it is easier to use a spokeshave to even things out.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

After the edge is pared to the length and thinness desired, I rotate the knife into the third position, so that it is not skewed, and push it forward to even the previous cuts out.  This is almost more of a scraping action than a paring cut, and is meant to smooth out irregularities left from the previous cuts, not remove a lot of skin. The angle of the camera in the illustration seems to exaggerate angle that the knife is being held- in reality it is almost parallel to the skin. Again, a spokeshave could do this as well. The cutting edge of this knife is one inch, which is slightly larger than most turnins. Most of the time 7/8″ is a reasonable turn in width–compromising between giving a little extra room in case the leather is torn, and conserving leather.  One unintentional consequence of the acidic nature of some leathers is that they rapidly stain the pastedown, making it possible to observe in detail the pattern of trimming and size of turnins.  I admire the judgement (and frugality!) of some binders, capable of covering the book so economically that only a millimeter of two of leather extends under the pastedown in various places.

 

 

 

 

 

 

 

 

 

 

 

 

 

A roughly 45 degree angle seems to be the most comfortable in all three of the ways I hold the knife.  I have a set of knives that I use when teaching which consist of 22.5, 45, and 67.5 degrees, in order to compare what is most comfortable for each individual, and most opt for a roughly 45 degree angle. Another consideration is the angle of the wrist when using the knife– I’ve found around 40-50 to be most comfortable.  Keeping the angle of your wrist comfortable is important if you do a lot of production work, to avoid carpel tunnel syndrome.  Any numbness or tingling sensation is possibly a very serious problem, and medical attention should be sought.  Choosing a good quality knife, keeping it well stropped and sharp will also reduce the force needed to pare leather, reducing strain on the hand and wrist.  Finally, a 45 degree blade angle is much easier to sharpen than a 67.5 degree angle for two reasons– it is easier to get even pressure across the entire width of the bevel (especially the tip), and there is less metal to remove, so the sharpening is more rapid.  Paring leather is not difficult, as Johnson pointed out, it just takes some practice with a sharp knife, and an awareness of the blade angle.

 

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NOTES

1. As a left handed binder pointed out to me, simply changing the direction of paring allows a right hander to use a left handed knife, or vice versa.  Below I am comfortably using a left handed knife, holding the leather at the top and paring towards myself.  

 

2.  Some find it more comfortable to hold a knife with a handle.  In this case, it is sometimes necessary to hold the handle area of the knife off the paring surface in order to achieve a low angle.  This illustration also demonstrates side to side paring.