Feeds:
Posts
Comments

Archive for April, 2011

Knife sheath

This is a project I actually finished during the fall, and had not gotten around to posting until now. This was my first real experience with leather work, so I was not entirely sure what to expect, but it seems to have gone well and I am happy with the results. Here is how the process went.

The first step was to create a pattern Which would have enough leather to wrap around the knife handle and blade. I was getting bits of advise from a book called Knifemaking by Bo Bergman. It seems like a bit of a goofy book to me, since it actually doesn’t talk about making the blade at all, but is really just about making the handle and sheaths, but it does have lots of good information on those subjects. One of the sheaths presented in the book had the leather seem forming a spine down one side of the blade and handle, so I used that model as the starting point. I drew the silhouette of the knife and then added width on each side of the silhouette so that the leather would reach around to the center of the opposite side of the knife. I then added a little extra width on each side of the resulting shape to provide the extra material for the sewn spine and for the clamps to have plenty of material to hold onto. I think this step may be easier to see in pictures than to hear described. You can see the silhouette with extra width added drawn on the piece of paper to the right of the knife.

Next, I traced the pattern on the piece of leather and cut it out with a scalpel. My girlfriend keeps scalpels around which are surgical quality, but not sterile for bookbinding, and I have to say that they are awesome to use. Much sharper than any X-acto knife I have used.

To mold the knife around the knife, I first had to protect the knife from the moisture. I coated all exposed metal with some grease I have laying around for bike parts, and then wrapped a few layers of plastic wrap around the whole thing. To make the leather supple, I soaked it in warm water for about 15 minutes. A combination of small spring clamps and c-clamps with wood pads were used to hold the leather snugly around the knife. It took some work to get the leather pulled as snug as I wanted, but it was pretty simple to clamp parts of the sheath while working to get other parts more snug, and then cycling back around until the leather had formed around the knife to my liking, and so that the spine followed a path I liked. I left the sheath clamped up like this for 3 day so that the leather could fully dry and take on the shape of the knife.

After molding the body of the sheath I cut and molded another piece around the sheath around the handle of the knife. I decided to add this piece so that I could cut a channel in the body of the sheath for the sharp edge of the blade to pass through while pulling the knife out or putting it back in. This piece was also cut to have the belt loop.

After allowing the second piece of leather to dry for several days, it was time to begin sewing. The sewing required consideration to figure out a procedure which would work best. Regardless of which order I sewed pieces in, there would be some part that would be difficult. I believe the order I came up with was the optimal one. The first seam I sewed was the spine. I used a single piece of thread for sewing across the tip all the way to the opening of the sheath. I had two needles going at once, so each end of the piece of thread went through each hole. After sewing the spine I sewed the part around the handle on. To sew each side of that I first drilled the holes with a 1/16th inch drill bit, and I then cut the needles short so I would be able to maneuver them inside the sheath. Like the spine, I had two needles going at once. I also used additional needles to keep everything aligned correctly. Pushing the needles in was easy, turning them around and pushing them back out was difficult, but I got a system down which made it go reasonably smoothly. I used needle nosed pliers on the inside to hold the needle and then put a needle in the same hole that I was about to go out of, just far enough in to see the tip and give myself something to aim the needle on the inside of the sheath at. I would gradually pull the needle on the outside back out of the hole while working the needle on the inside into it. With the predrilled holes, this process went well. I imagine it would have gone poorly without drilling.

To finish it off I rubbed a little Obenauf’s leather preservative into the leather to slightly darken and protect it a bit from staining or water damage, but otherwise left it its natural color. The knife fits snugly in the sheath, and I am pleased with how it looks. It feels like I should be able to get a lifetime of use out of it.

Read Full Post »

One of the most fun aspects of the process building my Greenland kayak so far is that each step, while taking a relatively short amount of time, has created profound changes to how the boat looks. With just a few weeks of intermittent work, I have a frame which is beginning to look like a kayak. Here are the steps I completed taking up where the last post left off.

The ends of the gunwales have been fitted to each other by repeatedly cutting a kerf where the two meet. I cut the mating surface back until the surface was an inch tall at the tips of the gunwales. The bow was then pegged with three dowels that were wedged at each end. A string was then strung from one end of the boat to the other, and its location was measured at each of the braces to make sure the boat was straight. Adjustments were made as needed, and the stern was pegged.

Over the weekend I cut and fitted all of the flat deck frames. Most are 1×2 pine, while I made the frame which will double as a foot brace, and the two frames immediately behind the cockpit slightly wider. I traced out the shape of the two raised frames according to the instructions in the Cunningham book, and fitted them. I used a basic jig to clamp the frames in place while drilling them. Most frames received two dowels in each end while the ones which will take more stress received three in each end. Please note that there is one deck beam left to be installed, which is called the masik. It will double as a sort of knee/ thigh brace and I will fit that once I have the ribs and stringers installed, so I can get the fit just right.

Once the frames were installed, it was time to lash the ends in place. I drilled some holes near the temporary braces at each end, cut groves from the holes to the bottom of the gunwales for the lashings to sit in,  and cut some long pieces of artificial sinew. I lashed the gunwales according to the instructions in the Morris book. With the ends lashed I removed all the braces except the middle one. Currently I am planning  on keeping the middle brace in place until I have the ribs installed. Next step, I will be lashing the individual frames in to strengthen and tighten the structure up.

Read Full Post »

The next boat is taking shape! Despite the lack of updates on this project, good progress has been made on my Greenland kayak over the last few weeks. Even this update is somewhat tardy.

I squared up all 50 of the mortises, which was a very gratifying process. It was the sort of work I could just turn the music on for and set myself into a rhythm. With the mortises already drilled out, cutting them square went quickly.

Next, I got a little help from Emily holding a batten in place while I drew the curves in the top of the ends of the gunwales. The curves are supposed to allow the shear line to follow a continuous concave curve from bow to stern despite the hollows in the shape of the gunwales at the ends of the boat. The curves were cut with a combination of a slick and a block plane. The slick can be seen on the bench, and is one I made according to the instructions laid out by Harry Bryan in Wooden Boat issue 205.

I made the temporary braces to spring the gunwales into shape, and began determining the shape of the boat. The assembly started by placing the gunwales in the central brace. I then used a strap to keep the bow from spreading apart while I added the brace to pinch the stern together. I was then able to add the brace to pinch the bow together. After the end braces were slid amidships enough to create a slight hollow in each end, I added the last two spreading braces in front of and behind the midships brace.

With the braces roughly in place, the quest was under way to achieve just the right curve. Slight adjustments of each brace changed the shape of the boat in surprising ways, and without having built one before, it was hard to know just what the right curves would be, or whether I might be adding too much or too little volume to the front or rear of the boat. I read through all of the guidelines presented in both books and adjusted things to a curve that looks right to me. I guess we’ll see how it works!

*This posting gets me up to date with where I was at the beginning of the weekend that just ended. Lots of good progress was made over the weekend, updates are come soon!

Read Full Post »