Swivel Knife Preferences

[shtoink]

I'd like hear from you guys about your preferences in swivel knives in an effort to try my hand at making a nice swivel knife. Since my experience is somewhat limited when it comes to swivel knives and preference in how a knife should feel is very subjective, I'd like to here from you guys what it is that you prefer.

I debated making a poll for this, but decided against it due a high probability of completely missing out on some key details with the poll options.

I'd like to know what it is that you do and don't like. Things like materials, texture, grip, diameter of the barrel, size for the blade shanks, anything that comes to mind. Having a bunch of data from multiple sources helps me identify common features and also have a direct effect on what things should or shouldn't be added as features for my experiment.

As stated earlier, I'd like to give a shot at making a swivel knife and it would be very helpful to know what makes a "serviceable knife" versus a "great knife." This endeavor might lead to other things, but for now it's more proof of concept and getting familiar with my new lathe. Knowing what is preferred in a knife can help me make better choices about how I approach my project. I don't want to just duplicate something someone else already makes, that doesn't help. I also know that there are bigger fish out there, so this isn't any sort of delusional attempt at becoming a tool maker. I may end up making a small run, but I will cross that bridge when I get to it.

This boils down to one thing, I am an engineering student. If that doesn't clear it up for you, then you probably haven't met any engineers before. Simply put, It takes a special brand of crazy to find enjoyment in the things involved in being an engineer, but that's better left for another topic.

[shtoink]

I have noticed that at around 40 page views with no replies. I can't help but think that I may have been offensive or off putting somehow. I'm not sure how, unless there has been some misinterpretation, but there isn't any way to know that without any replies. Maybe it sounded a bit too much like some type of market research, maybe nobody wants to share their opinions on such things, maybe I wasn't clear enough.

I do want to point out that I wasn't looking for anyone to badmouth any tool makers' tools, in fact knowing the maker of the tool isn't even a requirement. I was really hoping to just hear what people had to say so that I might have a better idea on the direction my project should take and aid in me not wasting time and materials with bad design features. I deferred to those of you with far more experience experience in hopes of learning.

[HellfireJack]

It's probably because they're already discussing swivel knives in the same forum about 4 posts down.

http://leatherworker.net/forum/index.php?showtopic=42288

[shtoink]

It's probably because they're already discussing swivel knives in the same forum about 4 posts down.

http://leatherworker...showtopic=42288

Unfortunately, there was only a limited amount of details on what was liked or disliked there. I was hoping for some information along the lines of what I had asked in the post at the very top.

[Chief31794]

My likes,

Large Barrel, Smooth (ball bearing) saddle, sharp blade that holds the edge well. I'm old and my hands hold a large barrel better. I have recently changed over to ceramic blades and so far I like them, they take a little getting used to, but they cut smooth and never require sharpening, just stropping.

Dislikes,

Screw that comes loose (holding the blade in the barrel).

Chief

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Thanks Chief! That was exactly what I was asking for.

You made my day with that one.

[Woodyrock]

I can not help on the swivel knife, but fully understand the engineering approach being retired from PSNS N Engineering, and also live in the same soggy place. I have however thought that swivel knives should have a wider range of barrel sizes, both diameter, and length, to better suit both work at hand, and individual hands.

Woody

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I have however thought that swivel knives should have a wider range of barrel sizes, both diameter, and length, to better suit both work at hand, and individual hands.

This was my thought as well... I have pushed forward with some experimentation in different materials to both test the materials and hone my skills with a new machine. What a treat that is, I went from a PITA Chinese made lathe to a Sherline. It's not that those SEIG made lathes are entirely bad, but you need a machine shop and extra cash to make it reliable. I had neither, so I saved up for something that better suited my needs. I effectively went from an AMC Gremlin to a sporty Mini Cooper.

I have gotten feedback from a couple of sources about my first functional prototype, which led to making more prototypes. So far, the thing that seems consistent is that the knurling on most knives is pretty aggressive and unless you have burly, calloused hands they can prove uncomfortable for prolonged use. Weight seems to be a concern as well, but it seems to go both ways. Those favor of heft might have something to do with the opinion that heavier always means better quality.

All these opinions are the exact reason I deferred to those that have far more experience than I. Those opinions were developed somehow, and I wager it was though experience.

[St8LineGunsmith]

As I mentioned in another thread I would like to have one of the new tangle boss swivel knifes

I think it is revolutionary in swivel knife designs and when i am financially able I am going to get one

[shtoink]

I think it's time to let the cat out of the bag.

I have been working at trying my hand out on a start-to-finish design process. I set myself up with some design limitations and goals in mind and the results look very promising. I had very specific reasons for going about things the way I did and I will explain that later. I also had to identify and overcome a number of problems as the came up. Things that dealt with limitations of the chosen materials or oversights in tolerances of internal parts. Some my other troubles came about due to finding proper ways to organize my steps in machining or finding a certain tool that does the job more efficiently.

Since I am just one person and this is a personal project done on my free time, it won't be a matter of taking requests and making them my the hundreds. This is just my attempts at finding a current issue with an existing tool available and finding a possible solution. As a student with a Mechanical Engineering program, it's all about learning. This was the reason I was trying to enlist the help of others for advice or preferences as the provided certain details that I may need to focus on over others.

In an effort to keep from being to typically long winded about things, I'll provide some pictures and a general overview of my goals and what has happened up to this point.

I wanted to design a new knife out of a different material that would be both beautiful to look at and pleasing to work with. What I saw with the currently available swivel knives is that they are all metal and are usually heavily knurled for grip. This knurling can be aggressive and uncomfortable to the hand and the other issue is hand fatigue. That was a huge point for me. As I had asked around and one of the most common things that came up was hands getting tired after prolonged use and cold from the metal (some metals more than others). Aluminum and Brass will pull the heat from your hand quickly and if you have even the slightest hint of arthritis, it's going to aggravate it. Aside from the aluminum, the other commonly used metals are pretty heavy and many will equate the weight of an object to its level of quality. It's something that has to be put aside, as the weight of a swivel knife has no bearing on how well it will cut. Your hand is the driving force and a heavier knife means more work your hand needs to do to keep it moving and stable.

What I came up with is a common material that we have been using for a very long time, but I chose to use it in a new way. Wood. Specifically exotic hard wood, but still wood. The idea is that it will be lighter than the metal, feel nice in the hand, be lovely to look at, and reduce hand fatigue. The trick is getting it to survive the machining process and become a usable tool. One of the major problems has been the barrels splitting when cutting them or inserting the bearings. This led me to try out different species of woods and I am sticking to those very tight grain structures that aren't brittle.

The first two images are of the first functional prototype. The third image is of what was usable from the second prototype that broke and parts built to create a third prototype. These two are made from the same African Blackwood, which accounts for their similarity, and are out in the wild undergoing long term testing that I just don't have the expertise to do. The third picture was taken before I replaced the setscrews with nicer, more professional looking ones. The next two images are of a shorter version (2") made from Bacote and the bigger one made from Snakewood (2.25").

From the testing so far, the feedback has shown that these knives perform phenomenally well and are a joy to use. Also, reduced hand fatigue, which translates to longer times being able to cut leather without your hands paying the price.

Just click the images to open up a full size picture.

Functional Prototype 1 (P1):

Functional Prototype 2/3 (P2/3):

Barrels for further prototypes:

New barrels and P2/3 for comparison:

At this point I am just sharing what has transpired. I have still been testing out different lengths and diameters, but there is a limit to the minimum diameter I can make based on the limitations of the materials used and the size of the bearings I am using. This means that about 0.5" on the barrel is the smallest i can go. I may do up some blueprints with dimensions and notes for those that feel like making your own, but that'll be later. I will probably be making a few to sell, however I want to work the last few bugs and optimize the production process without a reduction in the level of quality before I hit that point. If I don't, they'll need to sell for far more than I think they should to cover the time I spend machining the internal parts.

The post did get lengthy, and I am sorry for that. I actually left out a great deal of the boring details and failed experiments I made in the process.

Feel free to chime in with your thoughts, but I mainly wanted to further explain the purpose of my original post and share some eye candy.