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

[shtoink]

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

[shtoink]

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.

[pete]

what intrigues me the most is the shape of the yoke. I don't know if you can improve on the 100's of knives out there, but the yoke LOOKS like it would be very comfortable !!!

You might have a market on the yoke if it fits the shaft of the most common and popular knives!!!I'll be glad to try one and send it back with a critique. I have leatherwrangler and chuck smith knives.

I'm serious about the offer. I would buy one if it feels as comfortable as it looks.

pete

Edited November 16, 2012 by pete

[shtoink]

what intrigues me the most is the shape of the yoke. I don't know if you can improve on the 100's of knives out there, but the yoke LOOKS like it would be very comfortable !!!

You might have a market on the yoke if it fits the shaft of the most common and popular knives!!!I'll be glad to try one and send it back with a critique. I have leatherwrangler and chuck smith knives.

I'm serious about the offer. I would buy one if it feels as comfortable as it looks.

pete

I'd have to find a way to make my yoke fit the craftool standard knife. Not impossible, but a different direction than I am going at the moment.

The yokes I made are very comfortable. The design started out as an attempt to find an ergonomic for my hand and evolved from there. The other factor was that the material I was working with started out as a cylinder and I was just working with what I hand on hand. As it stands, making the yoke still remains the most time consuming part of making these knives. I haven't found a way to machine them that doesn't require equipment I already have. I could probably do it in multiple steps with a CNC mill, but that is something I don't have at this point.

They do feel different than the standard shapes used on other knives, but this whole endeavor, yokes included, has been an effort to find a solution for a problem that is not addressed by any other knives on the market. Hand fatigue.

[TwinOaks]

I lost track of this thread, otherwise I would have chimed in sooner.

I spoke with Shtoink at length about the design process long before he started this thread and he sent me the first prototype (P1). I've done some test carving with it, but I don't claim to be a master carver. Here is the report I sent:

"Before I started the test, I sharpened and stropped the blades I would use. Blade 1 is a standard 1/2" square tip, blade 2 is a 1/4" angle. I used the Woody, and a standard swivel knife side by side, and swapped blades so that the blade wasn't a variable. Pattern is Tandy's Celtic Cross.....first time I've ever carved it. The carving session was straight through with no break except for the transition between knives and the blade swap. Leather is S. American from Springfield, and cased with tap water - no conditioners.

Results of the swivel knife 'test drive':

Obviously the Woody has a smoother action. I've already mentioned that aspect, and that was why I sharpened/stropped both blades.

Temperature in the house is high 60's because it got chilly last night and we've been pulling 'night air' in to keep the house cool.

There is a noticeable temp. difference to my hand between the two knives. Though the Woody never felt 'warm' (higher than ambient), it never felt cold. If I'd kept it in my hand instead of swapping, it may have felt warmer due to body temp. transfer to the wood.

The tandy knife felt cold every time I picked it up, and that definitely had an effect on comfort.

Knurling on the tandy knife is tactile, but not overly aggressive. However, it did effect how I had to move my fingers to adjust position. Woody is grippy, but not like a rough texture.

Regardless of which blade was in the tandy knife, I was stopping and flexing fingers as I moved from section to section. With the Woody, I just moved the leather, or twisted the knife and kept going. About halfway through, when I'd determined which blade was cutting better, I just put it in the Woody and finished the whole carving with it....no stopping...then went back and connected some of the cuts I'd stopped short.

Your expectations of the improved ergonomics of the wood barrel are right on spot.

Total carving time is about 45 minutes, with the majority of the cuts made with the Woody.

**Of particular note:**

When I transferred the pattern to the leather (make a copy, then trace the lines on the copy while overlaid on the leather) I WAS getting some minor cramping. The pen I used has a steel barrel and was at ambient temp. - same as the tandy knife. The wood barrel was comfortable for pretty constant use."

I'm an electrician, and work with my hands on a daily basis indoor and outdoor, warm or cold. Because of this and some injuries to my hands (voltage burns) I have arthritis already starting in a few joints/knuckles. If you have the beginnings of Arthur, you know how cold things effect your hands. With this knife, I was able to carve nearly nonstop for 2-3 times as long with far less fatigue.

Also important to note is that the knife is smooth enough to feel the problems I had with my blades....which I didn't know about because they were in standard knives. The standard knives just didn't transmit the feel of the cut the same way.

Regarding the yoke: I was a bit skeptical at first because it is so different from the standard yoke. I find it to be MORE comfortable than the standard yoke. The wood (as mentioned above) never feels 'cold', and even though it is thinner, it is rounded in two axis. That allows me to hang my finger in the yoke in a variety of positions without ever having an edge....very much like a saddle yoke. It is shallower but wider, than the saddle yokes like on the sk-3 knives.

Hm...what more to say about it? It feels good in the hand. I also have a BK knife, and it's very nice....but this design feels better, and hence works better.

[tnawrot2]

I have big fingers, and they won't fit in a lot of yokes. I am interested in your yoke, is it padded?

[TwinOaks]

It is not padded.

[shtoink]

I have big fingers, and they won't fit in a lot of yokes. I am interested in your yoke, is it padded?

The good news, I based it off of my hands and I have big hands.

That was one of the issues with the very first functioning prototype, it was big and would have been a very uncomfortable stretch for anyone with smaller hand. The barrel was close to 3" long, but I hadn't noticed that it was big until I had someone with smaller hands attempt to use it. It was kind of like watching a little kid attempt to ride a 10 speed. "Make shorter barrel" immediately went to the top of my list of revisions that needed to be addressed.

More good news, my yoke design is flexible enough to accommodate small hands with the very same yoke. I had a few women try out one of my knives and they had no issues with controlling or gripping the knife. So, as long as the yoke is appropriately sized, there shouldn't be any issues.

On a side note: One of my most dreaded fears is having everything exactly how I want it and then screwing it up later after discovering that part of my process needs to be modified.

A good example of this happened just recently. I worked very hard at perfecting the finish on the yoke shaft and keeping with looking nice while putting some threads on the end that connects to the yoke. I managed to mar it up pretty good when attaching the yoke to the yoke shaft. I was able to clean it up some, but the damage was done and I clearly needed to revise my process once more.

The previous revision to my process happened after doing something very similar. I had a nice and polish finish on the yoke shaft and marred up the finish getting threads on the yoke shaft.

Talk about frustration... I had some very choice words to say at the moment and I almost threw it across the room after that. That's all part of the designing and testing, though. Sometimes getting from step 1 to step two requires you to invent a whole subset of steps. Clearly, it isn't always smooth sailing...

When I get the chance, I'll post a few more pictures of the current one being constructed. I used the Snakewood barrel in the photos above, just to give you a hint at what it'll look like.

[shtoink]

I got a couple images taken with my cell phone after finishing up a recent test knife. As I mentioned in the previous post, this one is Snakewood.

As a reminder, these are cell phone pictures and not exactly the best quality, but it should give you a decent idea of how things have gone. As usual, these are clickable thumbnails that will open the full sized image.

[shtoink]

[Furiku]

Hello. This is my first post and I am new to leather crafting. I am familiar with swivel knives and understand their working but what I want to do in my work is to get a smaller, thinner, detailed cut in some of my smaller designs. To do this I began using an Exacto knife. My question is, "Could a swivel knife be fitted with a much smaller blade similar to the blade of an exacto knife?"

I realize that my inexperience may to blame for going to this type of cutting tool. The areas I am trying to work in are so small, a regular swivel just cuts too big.

Thank you for your time,

tom

[chancey77]

How did I miss this thread! Dude this is awesome!

My biggest problem and pet peeve is that dinky little set screw that rusts or strips out because of rust!

Man your wood shafts are cool!

Also heavy bottoms and fat design!

Edited January 15, 2013 by chancey77

[Arrow K Braider]

When using my swivel knives I can't seem to find one that is long enough for my hand. I have shorter wider palms and longer fingers. This has also given me trouble in finding one that is also thick enough.

[shtoink]

Hello. This is my first post and I am new to leather crafting. I am familiar with swivel knives and understand their working but what I want to do in my work is to get a smaller, thinner, detailed cut in some of my smaller designs. To do this I began using an Exacto knife. My question is, "Could a swivel knife be fitted with a much smaller blade similar to the blade of an exacto knife?"

I realize that my inexperience may to blame for going to this type of cutting tool. The areas I am trying to work in are so small, a regular swivel just cuts too big.

Thank you for your time,

tom

There are many sizes, shapes, and types of blades for your swivel knife. Depending on how many you have, you may want to have a specific blade mounted into each knife body. I know that isn't a universally common theme, as others may only have one or two knife bodies and need to swap out the blade as needed.

When using my swivel knives I can't seem to find one that is long enough for my hand. I have shorter wider palms and longer fingers. This has also given me trouble in finding one that is also thick enough.

This is one of those things that I think I may have worked out. I am probably not the only one that came up with a design that might work for you, but the shape of the yoke and a really wide range of adjustability of the yoke height make it very friendly for a wide range of hand shapes and sizes. The only downside I see with mine is that I have a minimum size for the barrel based on the limitations of the wood and bearings that I am using. Basically, I'm stuck with a minimum size around 0.5". Working on a smaller design is on my to-do list, but I have other things to work out first.

[shtoink]

One of the materials I have been experimenting with besides wood has been titanium. The reason being, it is a poor heat conductor and light weight. This means that it will feel warm in your hand in a very short time. The one really big shortcoming is that it's not the easiest to machine with HSS tooling. It can be done, but it requires frequent breaks to cool and resharpen the tooling.

This link below is my first cut into a bar of titanium and it got hot enough to ignite the oil I was using for cutting fluid. The chips were coming off glowing white and somewhere in the neighborhood of 2000 °F. I clearly had my speed a bit too high and have since not had chips come off that hot.

http://s7.photobucket.com/albums/y285/shtoink/?action=view¤t=cutting_titanium.mp4

The other solution is to get some Tungsten Carbide tools to do the job, but the downside is that it's not a cheap option, but that's why I spent a good deal of time trolling around ebay for low-cost deals. That's what the following picture is about. I managed to score some carbide drill bits, spiral fluted taps, and a couple reamers. The taps and the bigger reamer are HSS, but will be used gently. If I had purchased all of this at retail, it'd probably be in the neighborhood of $300, but I'm a cheapskate and I have about 1/4 of that or less into them.

This is partially related to the process of making the swivel knives in the sense that it really helps to have the proper tools to do the job once in a while.