It’s been a little while, but I’ve finally found some time to sit down and share some of our recent experiences in the Bookbinding program.
Two weeks ago Jeff Peachey, conservator and tool aficionado, came up to North Bennet to teach a three-day knife making and sharpening workshop. This past summer I got to work on my sharpening skills a bit with a Tormek grinding system and the conservation staff over at the Parks Library at Iowa State University (you can read that blog post here), but I learned a great deal more about doing things by hand in this workshop. Jeff has been coming up to teach sharpening at NBSS for a few years now and divides his time up into general information sessions and class-specific activities. While the first years were busy making our own sharpening kits and knives, the second years were re-sharpening their blades and modifying spokeshaves for leatherwork. This blog post will focus mainly on the knives as I was too busy to go over and really see what the second years were doing. I’ll just have to write about spokeshaves next year:)
First off, we all gathered around a table in the workshop with a range of abrasives and different styles of leather paring knives.
Jeff went over the typical abrasives that one would typically use to sharpen (silicon carbide, aluminum oxide, and diamond), as well as some of the naturally occurring materials that can be used (shark and stingray skin, garnet, and emery). He spoke briefly of the strengths and weaknesses of Arkansas stones, Japanese water stones, and ceramic stones and which lubricants one must use to keep metal particles from getting lodged in the stone (aka Glazing). Jeff also gave us a crash course in the properties of the various kinds of steel that we would be using that week and which abrasives would work best for each.
Next we spoke about the different characteristics of English, Swiss, and French style leather paring knives. Jeff demonstrated some different techniques for paring that one might use depending upon the style of knife that they prefer and instructed us to begin thinking about the kinds of knives that we would like to make over the next few days. In the meantime, he got the first years started on small lifting and English style knives. We started out with the 0.5″ Starrett “Redstripe” hacksaw blades.
We used these hacksaw blades specifically because they are fully hardened molybdenum (M3) high-speed steel. You can get them in a couple of different widths – which are useful for making a variety of knives – but we started small to get the hang of the process. After sanding the paint off of both sides of the middle of the blade, I marked the approximate angle of my knife on the blade, tightened it in a bench vise, and hit it with a mallet to break it in two.
All of our leather paring knives have a single bevel with a length that is 4 times the thickness of the blade and an angle of 13 degrees; a bevel that is any lower will be weak and bits will chip off when using the knife. Jeff showed us his method for putting that bevel on quickly with the grinder.
Then we were ready to finish the knives by hand… but first we had to make our sharpening system!
Jeff has been using a set of two aluminum plates with 3M Microfinishing film adhered to each side for some time now. At the beginning of the workshop, everyone received two 12″ aluminum plates. These pieces do not come perfectly flat (they are a bit dished out toward the centers) and we had to fix that in order for our sharpening to be effective. And the only sure-fire way to do that is by hand. So everyone smeared their plates with some silicon carbide grease, placed them together and began lapping.
As you can imagine, this part did not go very quickly. For some, it went on the rest of the day. With the compound on the plate, you can’t really tell if your efforts are having any kind of effect. So you lap for what feels like an eternity, then wipe it away to reveal that your plates are not quite flat yet, and start again. The image on the left will illustrate – the areas of the plate that are not experiencing contact are lighter than the parts that are making contact. When the aluminum is finally completely flat, different grits of microfinishing film are applied to each of the 4 sides of the plates: 80 micron, 40 micron, 15 micron, and 5 micron. The image on the right shows the completed plates.
If hand lapping for hours (or days) is not your thing, Peachey sells this system on his website (here). One can also use glass – the advantage is that it is already flat, but you have to worry about it breaking.
Now that we each had a sharpening system, we were able to finish the edges of our blades through a two-part iterative process. Starting off with a diamond stone (we used a DMT Duosharp) or the 80 micron microfinishing film and a little water for lubricant, we worked the flat side of the blade until it was actually completely flat and a burr could be felt on the bevel side.
We then worked the bevel side of the blade until a burr could be felt on the flat side – all the while checking to make sure that we maintained our 13 degree bevel angle.
We would then switch to a finer grit and repeat the process until we had used every side of our set of aluminum plates. The cutting edge was finished by stropping with the flesh side of horsebutt dressed with chromium oxide and then polished with the flesh side of calf skin. The result is a mirrored, wickedly sharp knife. These are my first two attempts from the 0.5″ hacksaw blades.
As a side note: this particular knife shape, a kind of English style with a rounded cutting edge at the heel, is apparently favored by Christopher Clarkson. I have yet to really try it out and cannot comment on the situations in which it may be more appropriate to use than a straight bevel at the heel of the blade. But I’ll keep you posted as the year goes on.
After we had made a few blades with straight bevels, Peachey demonstrated the various techniques for sharpening a curved edge.
At the beginning of the workshop I picked up an A2 and an 01 steel blank for making a smaller Swiss style knife and a larger lifting knife. These came with a 13 degree straight bevel already on them, so I just had to modify them a bit. Aside from rounding the sharp corners, I made the bevel on the lifting knife a bit shallower with the grinder. As with the hacksaw blades, these were also finished by hand using the aluminum plates – but with a curving motion. The before and after shots appear below.
On the third day, Jeff went over a few ways to make handles and sheaths for the knives. I tried something different on each of my knives, figuring that I would give them all a try and re-handle the ones that do not feel comfortable. The knife below on the far left is a blade with a double bevel (pretty difficult to do well and mostly me just messing around with a bit of extra 1″ hacksaw blade) and has a wood handle. For the larger lifting knife (second from left) I just rounded the edges and left it without a handle so that, should the need arise, it can be used to lift material in water. The Swiss knife (at center) is wrapped in flax cord, while the lifting knife beside it is covered in calf skin. The small rounded lifting knife to the far right has a simple horsebutt handle. In each case the handle is adhered with PVA.
The sheaths were also relatively easy to construct. Layers of leather and or 20 pt board as thick as the blade are sandwiched between two pieces of horsebutt and adhered with PVA. I gotta say, these are infinitely better than my previous sheath attempts made of Davey board and duct tape. By the end of the 3rd day I had completely sharpened, handled, and sheathed 6 knives of various shapes and sizes.
Aside from knives and spokeshaves, Peachey’s workshop included a range of other demonstrations. He showed us a method for sharpening scissors with a diamond stone and a vice.
(Here Jeff’s arms are moving so fast I can’t get them in focus… but the photo illustrates the action.)
Jeff also blew my mind with this nifty trick to make leather strips. He first cut a circle of leather and basically nailed it to a shooting board with an awl.
Then using a paring knife, he started a thin strip and just kept spinning the leather to make a long, thin length – kind of like peeling an apple.
Finally, Jeff showed us how to make small Japanese bamboo lifting knives, called hera, with a short length of bamboo and a chisel. After splitting a piece of bamboo with a chisel, Jeff squared it up…
… and shaped the blade.
The rough shape from the side looks like this:
The tool is then sanded down with a range of sandpapers (from 150 grit to 400 grit) and polished with 3M Tri-M-Ite polishing paper. Finally a light coat of Renaissance wax is applied to the top of the blade.
You can read his description (with better pictures) of the hera on his blog here.
All in all, this was a fantastic workshop. Thanks to Jeff’s patient and thorough instruction, everyone came away with a much better understanding of sharpening and quite a few more tools. It will be interesting to see how I end up using these tools over the coming months. Will their present form really live up to their intended function? That will be the true test. If not – at least I now have the equipment and know-how to fix them.