Sunday 13 May 2012

8. Paring the Leather


We now need to pare the leather so that it is thin enough to work at the turn-ins and reduce the bulk along the edge.
Before we start attacking the leather with sharp pointy things, we need to make a template so we can cut a piece to the correct size. I usually use a Bulky Newsprint, but I seem to have none in stock so standard newsprint will have to do today.



Start with an oversized piece and making sure you have a right angle on at least one corner, mark a border 25mm along the top and down the left side. These will be the head and left fore-edge. You don’t want more than an inch excess around the boards as the larger they are the more pull they will exert on the board and cause excessive warping.


Lay the book front board down on the marked paper and mark the tail and the edge at the spine.



Holding the book down, firmly smooth the paper over the spine and crease around the backboard.

 
Now lay the paper flat and the crease marks should indicate where the backboard will sit. Mark it in, along with the spine area and the 25mm excess all around. Cut it out and your template is ready.

 

 
Use the template to cut a piece of leather from your chosen skin. For this book I have chosen a deep chestnut coloured Calfskin. Once cut out transfer the marks from the template to the flesh side of the leather.


Ok, for the paring process I’m going to use a combination of English and French paring knives and a flat-faced Spokeshave. Your knives have to be as sharp as possible, so always spend time checking for nicks or burrs. For sharpening the knives I use a 600 grit wet and dry paper glued to one side of a piece of 6mm MDF, and on the reverse, a piece of leather for stropping.
The surface you pare on should be strong flat and smooth. Most binders seem to favour old Litho stones as they are more sympathetic to the knifes edge. They are, however, quite hard to get hold of. I use an old inking ‘stone’ which is actually steel but you could use a thick piece of glass or granite.
With a piece of wood to protect the leather clamp it to the stone to keep it steady.  



 
Our first job is to edge pare the leather to take the majority off so that when we use the spokeshave to literally ‘shave’ the leather, the shavings won’t build up and tear it.
To do this place the point of the knife on the stone, and using a shallow angle, draw the knife across the edge. This does take a lot of practice, and I’m by no means an expert. Definitely practice on off cuts and spare pieces, you may find a technique that suits you better.


Once the edge has been angled about 6/7mm in, you can start using the spokeshave.
The spokeshave needs to be modified for use on leather rather than wood. This link will guide you through the process, http://www.hewit.com/skin_deep/?volume=16&article=2
Starting about 15mm away from the 25mm line, push the spokeshave away and off the pared edge. Shave all along the edge evenly; repeat until the thickness has been reduced significantly. Brush the shavings off the leather and from under it regularly. 



I’ve read that it needs to be 0.4mm or so, but you will before long get a feel for how thick it should be. As long as you bear in mind that it has to form around the edge of your boards, you can make a decision as to how thick it needs to be. The image below shows the same leather folded before and after paring.




Once the edge has been sufficiently thinned, feel for any uneven areas and rectify them. Once done move on to the tail and then finally the fore-edges.



Our next stage is to further pare the areas of the turn-ins that will form the head caps. These are the areas that will be turned and tucked into the hollow back, and therefore need to be thin so as not to form an unsightly ridge. 



For this process I use either the rounded French paring knife or the heel of the English paring knife. I then take the edge right down to the hair side so it’s incredibly thin.

The corners need now to be cut at a 45% angle. You need to leave a small gap between the cut and marked rectangular area of the board. This is so the board won’t poke out when covered. The measurement for this should be about a board and halves thickness. But I tend to leave around 6/7mm.


Cut the corners and edge pare them very thin. 

Finally feel the entire surface of the flesh side and what you may feel is a noticeable step between the original thickness of the leather and where you have pared it. This needs to be rectified or it will be visible when pasted down. Using the spokeshake gently reduce the step, feeling constantly for uneven areas.


When finished reapply the markings and the job is done. 










4 comments:

  1. Steel paring knife
    Amusing marker.
    Good information nowadays.
    Thanks for sharing with us.

    ReplyDelete
  2. The paring knife seems to be the most essential kitchen knife which is perfect to be placed on the kitchen desk of your modular kitchen.

    ReplyDelete