First page of the #screwdrivers archive.

Leather for cylinders – How?

Posted by is9582 on March 11, 2016 with No Commentsas , , , , , , , ,

I have two of the screwdrivers that are offered by Lie-Nielsen Toolworks, the No. 4 which is the stubby straight blade used on the chip breaker’s screw, and the No. 2 which is another stubby used on the split nuts on Lie-Nielsen’s hand saws (I’ve found it doesn’t fit all of my vintage saws, but that isn’t a ding, as they made it to fit their saws). When I take some hand planes or hand saws with me to another site, I of course bring these screwdrivers along, but they’ve always just been loose.

I was thinking about another potential job last week, and I had a little spare time, so I drew up a pattern for a leather holster with which I’d carry my Lie-Nielsen screwdrivers, and they wouldn’t get banged around, nor accidentally ding another tool. When you are dealing with leather, it can be very simple to lay out your pattern if the item isn’t too complicated. When you look at these little screwdrivers, they really don’t look like they should be much trouble, but lots of little details play into how easy the leather behaves. If the leather is super thin and flexible, I find it quite a bit easier, as the leather will just conform to the shape you ask of it. With thicker and not as flexible leathers, it can get a bit more tricky! I had leather that was fairly thick, but also somewhat flexible, so I was hoping it would kind of balance out.

Ok, back to talking about coming up with a pattern, which again seems like something that you just draw some lines and get going, right? Well, on cylindrical or conical items, like these screwdrivers there are a couple of ways. I initially went with a very simplistic method, which was to take a piece of paper, and wrap it half way around the screwdriver, and mark the two end points. This would, in theory, match up to exactly half the shape of the screwdriver, and since I was making it from two pieces (or halves), the two together would be the perfect fit for the screwdriver.

 

Paper pattern I created so I could make the leather screwdriver holster.

Paper pattern I created so I could make the leather screwdriver holster.

 

Ok, before I talk about the other details that also need acknowledgement, let me share what it probably the more precise method for obtaining measurements for your pattern. This second method will use a little math from school, but don’t go run and hide just yet, as I’m giving you the equation and will explain. With the shape of the screwdrivers, if you cut straight across the handle and look at the end, you’d see a circle. As some of you may recall, to get the distance around a circle (the circumference), the equation is 2πr (you multiply 2 times Pi, times the radius). Since this holster is made from a front and back piece of leather, each will deform to fit half of the shape of the screwdriver, changing the equation to πr, for each piece. If you aren’t sure how to get the radius of the handle, just measure across the thickness with something accurate, like a digital caliper. Whatever value you measure, will need to divided by 2, as your measurement is the full diameter, of which the radius is half. And if you don’t have a fancy calculator that has a key on it for Pi (π), you can just use 3.1415 which will be plenty accurate enough. Ok, that was the toughest part, and you made it through. (Or at least I hope you did. Maybe another cup of coffee??)

With the information we now know, we can draw out our pattern. After laying out the location for the stitching on one sider, measure over the distance you calculated, and mark for the stitching down the center of the holster. Measure the same distance again, away from the first line of stitching, and this will create the space for the second screwdriver. I chose to have stitching across the bottom of my holster, to keep the tip-ends completely protected. I physically laid the screwdrivers on my developing pattern, to decide how much room to allow, when the leather deforms when the screwdrivers are pushed into the completed holster. Just remember that as the two sides are pushed outward, the closed system of leather, will cause the bottom stitching to pull in towards the tip. If you have really flexible leather, this could be a decent amount, but it wasn’t too bad with the thicker leather I used.

Before I talk about the actual creation process of this holster, let me share one more caveat in the pattern/design phase of leather working. As I’ve mentioned, the leather thickness and stiffness can readily affect the end results. Even with the ideal leather and the calculated measurements I spoke about above, remember that as we hand stitch the leather with the saddle stitch, we pull both lines nice and taut after each hole. This is the best practice, as it keeps the thread/sinew/… down and protected from damage, but this also can add something to this design. Since it is taut, the stitching is keeping the two pieces together, and the force spreads out slightly, so it isn’t just at a single point. This is along the lines of sharpening when you are attempting to reach a zero radius at the tip of the blade to have perfect sharpness. In this leather, the spreading of force causes the measurements on which we based our design, to in essence shrink slightly, as the force spread is causing leather that was anticipated available to flex and shift, to be bound down. So what I’m saying, is you need to take this occurrence into consideration, so you can have a fudge factor (or whatever you wish to call it), providing enough flexing material between the areas under force, as you would have in the perfect world. Unfortunately I can’t give you a value that will always work, as the differences in the leather you may use will have a fair contribution in the amount of this behavior. Ok, so you’ll need to get busy testing and trying different materials and keep a log, so you’ll know what to expect when you again use a certain type of leather. On with this creation…

I cut out two pieces of leather, with the first the size of my paper pattern. For the second piece (the back of the holster), I added a little over an inch to the length of the front piece, so the handles wouldn’t stick beyond the leather on both pieces. I marked where I planned to stitch, along the three edges, and then also for the center row of stitching. Before using contact cement to lock to two pieces together, I always use a multi-toothed thonging tool to create the stitching holes in the top piece.

 

Top piece of leather for the holster, with the holes created from my 4-tooth Thonging tool.

Top piece of leather for the holster, with the holes created from my 4-tooth Thonging tool.

 

I’ve had too much variation in how the thonging tool behaves, when trying to go through multiple layers of leather, at the same time. After all of the holes are created in the front piece, now the contact cement is applied. Its a workflow that is good for me, so give it a try if you’d like. After the pieces are cemented together, I use the single-toothed thonging tool, going through the holes in the top piece that I made earlier, and creating the holes in exact alignment on the back piece.

From this point, almost everything is exactly the same as in my most recent leather project, which you can read here, except for one thing. Rather than stitching from the start to end, with one continuous thread, on this piece the outside perimeter is handled in this way, but the center line of stitching is accomplished after the other stitching is done. This center section is stitched with one continuos line of thread, but is not attached to the perimeter stitching. As I still used the saddle stitch, it is still just as strong as any other leather stitching I’ve done.

 

Lie-Nielsen screwdrivers against their new traveling quarters.

Lie-Nielsen screwdrivers against their new traveling quarters.

 

My Lie-Nielsen screwdrivers in my new holster.

My Lie-Nielsen screwdrivers in my new holster.

 

I hope this article is helpful with understanding just how to calculate where to stitch for a given item. As always, please let me know if you have any questions or comments. You can also check out my Instagram page at @LeeLairdWoodworking and my Twitter at @LeeLairdWW.

Lee Laird