Tell me about slip joints!

[ARCustomKnives]

Hey guys.... I'm fairly new to this whole knife making thing, and as of yet, I really haven't done much more than build a grinder and practice some grinds.

When I first got the idea in my head to try my hand at making some knive, I'll be honest: Slip joints were the LAST thing on my mind. Honestly, I figured that fixed blades would be my main focus starting out.

However, after looking at some of the beauties in THIS forum, I'm really getting the urge to try my hand at some slip joints now.

So, that's where you guys can hopefully help me.

Any links to tutorials or beginning info would be much appreciated.

Also, for the spring: is this heat treated and tempered much like a blade? or is there a different process involved?

Is the same material as the blade generally used?

How do you guys cut your nail nicks?


It's funny. Normally a slip joint would be the last kind of blade I would consider buying or trying to make, as they are usually slower to open, and don't have the added safety of a lock.

But after seeing some of the amazing creations you guys are coming out with, I might just be converted!

[zerogee]

Originally Posted by Bassthumper

....
However, after looking at some of the beauties in THIS forum, I'm really getting the urge to try my hand at some slip joints now.

So, that's where you guys can hopefully help me.

Any links to tutorials or beginning info would be much appreciated.

Also, for the spring: is this heat treated and tempered much like a blade? or is there a different process involved?

Is the same material as the blade generally used?

How do you guys cut your nail nicks?

Tutorials: look at Don's Texas Toothpick construction project thread above. ^ Chris Crawford's tutorial: http://boseknives.com/backpocket-construction/ (this is a very good start from scratch tutorial). Also Tony Bose putting together one of his backpocket knives in ivory (assembly and tuning, but no design or heat treating and tempering in this one): http://boseknives.com/backpocket-construction/

The spring can be heat treated just like the blade, there's no need to get fancy with it -- only you must temper them back to spring temper, which is from about 43-49RC (more than 50RC your spring will probably break on you sooner or later) -- whereas your blade will normally be tempered to about 58-61RC. Chris's tutorial covers a bit of tempering a spring properly. Most people use the same steel as the blade - if for no other reason than using the same piece of barstock, so your spring and blade start out the exact same thickness (you can save yourself huge headaches by buying good precision flat ground barstock -- keeping everything flat and square is the core mantra of folder making).

Everyone cuts nail nicks different - but the usual techniques include a shaped grind stone on a Dremel or equivalent or a fly cutter on a vertical mill (I've even seen one tutorial where they took a triangular file and heated a small section to red, bent the file about 90 degrees (with one of the corners of the file outermost) and quenched it - then used that sharply bent section to cut their nail nicks - this requires a quality file like a Nicholson or similar that are made from solid high carbon steel). Some methods require cutting the nicks before heat treat. Or, of course, you can just build an easy opener with a large semicircular cutout in the handle and you won't need the nail nick at all.

My recommendation is to get a cheap slipjoint (a cheap, mostly used up beater made by a quality maker is best) of a pattern you like, take it apart, and use it for your starting pattern.

[CWKnifeman]

Look at some of the sticky threads in this fourm. As well as some listed in Tony Bose how to's. One of the best things will be to get a folder kit to see where everything comes into play. There are a few things that you will need to understand about folders get a few bookson the subject: Custom Knifemaking by Tim McCreight is a good palce to start in both folders, and fixed blades; and How to design and make your own folders by Jerry Van Eizenga.
Just for starters.
Curtis Wilson

[ARCustomKnives]

Thanks for the suggest guys! Keep 'em coming.

I definitely plan on examining the old slip joints that I currently have, as well as buying a cheapo to take apart.

I remember I had a cheap Swiss Army Knife knockoff that fell apart as a kid. I wish I would have saved the parts.

I'm also thinking about buying a pre-made knife kit such as are offered on this site:

http://store.greatlakeswaterjetinc.c...tegory_Code=TF

and finishing them.

These are about as bare bones as you can get without cutting the stock yourself, and a little cheaper to start out with probably.

[zerogee]

Originally Posted by Bassthumper

.....
I'm also thinking about buying a pre-made knife kit such as are offered on this site:

http://store.greatlakeswaterjetinc.c...tegory_Code=TF

and finishing them.

These are about as bare bones as you can get without cutting the stock yourself, and a little cheaper to start out with probably.

I think these are a great choice -- be sure to read a bit on Don's toothpick thread about some of the details of what you will need to do once you get one of these "kits". You'll still need to flatten the stock a bit and square the edges (waterjet cuts leave a bias). For greatest simplicity to start with, I'd recommend using micarta scales and making them shadow patterns (no bolsters).

[doublearrow]

Some advice I have about slipjoints is that you have to be half crazy to start one and by the time your done you will be certifiably insane. I look at a slip joint and think a blade, a spring, liners, and pins and you've got a knife. The concept is simple, but there's a ton of tricks I picked up in the above mentioned tutorials that I would not have picked up on. I am by no means an expert, I've made 5 all with the help of these forums. It's amazing how different each one is from the same pattern. They all take tweaking in different ways.

As for nail nicks I couldn't cut one with a dremel that didn't look like I hacked at it with a dremel, so I used an idea I saw on some other knives. I used silver wire to make the nail studs. It's a little different looking and some collectors actually hate it, but I did get alot of good feedback. It's fairly simple to drill 3 holes then use two brass rods with holes drilled in the ends to dome the pins. Here's the first one I tried

Here's another trick I used, I wanted relieved liners so that they did not scratch the tang when opening and closing. I didn't have a mill so I used a resist to not etch the shiny area and used my homeade etcher to remove .005" around the pivot to make a relieved liner.
Here's the practice piece.

[Crockett]

Originally Posted by Bassthumper

How do you guys cut your nail nicks?
!

You're getting excellent advice in this thread, I couldn't add anything more. The way I do my nail nicks is...well I've done some with a dremel cutoff wheel and arbor mounted in the drill press and the blade held in a cross-travel vice. I feed the blade back and forth, and gradually into the wheel untill I have what I want. I mark the blade before hand with a Sharpy, drawing a line to represent the nick. Then I try to cut away the mark, if that makes sense.

I like the look of the resulting nick when done this way, it's a straight slot with ends that wind up somewhat rounded.

I have also dressed a very thick 3" dia. cutoff wheel at 45 degrees (using a diamond wheel dresser) and used it to cut nail nicks, by mounting the blade in my lathe milling attachment and moving it up into the wheel (s-l-o-w-l-y). The wheel is chucked into the lathe and spinning as fast as it will go. This results in a very nice, factory-lookin' nick but it does require more planning. The depth that you're going to cut to, the diameter of the wheel and the angle it's dressed to will all effect the look, and the length of the nick.

I use abrasive cutoff wheels because I like to make the nick after the blade is hardened and finish ground. The reason is I'm still very new to these slip joints and I'm still learning. I never really know where my grind lines are going to be untill I'm done with the blade!

Don

[Crockett]

Oh and for the record I REALLY like those nail studs!

[zerogee]

Another possibility for nail nicks is to simply cut a slot thru the blade like in Scagel style folders (see the Scagel style folder thread a little below for some images). And I agree with Ryan (and Crockett) -- don't try to cut nicks with a hand held Dremel - use some means to securely lock down both the blade and the tool and bring them together precisely, otherwise it will look like total crap. Kaj Embretsen uses the blade studs instead of a nick in many of his folders - I think they look great, but I'm not sure how I would like them in use though (I'm mainly concerned with them getting in the way when slicing thru something), will have to play with that sometime.

Tony Bose says that the primary attribute a beginning folder maker needs is a whole *lot* of want-to -- and being a bit crazy is a bonus.

[ARCustomKnives]

Wow, I'm getting a lot of good info here! Thanks guys!

I just got done reading through the majority of Don's Texas Toothpick thread, and I'll say one thing:

If I didn't want to build a slip joint before, then I sure do now!!

I definitely learned a lot of great details that I hadn't previously been aware of by reading through that thread alone. There is definitely a lot to consider when it comes to fine tuning one of these thing into a comfortable, well working folder. Things that you'd definitely take for granted just pulling one off the shelf and sticking it in your pocket.

Looks like I may have gotten myself into quite an undertaking, considering I haven't even made knife #1 yet.

But like Tony Bose said, I have a lot of want to, and no shortage of crazy.

As soon as I get a little side money thrown together, I'm gonna start stocking up on supplies. In the mean time, I think I'll start practicing some grinds on some 1/8" mild steel flat stock I've got laying around my shop.