is that supposed to be Texas?

Maybe if you squint hard enough. Lol

Getting the next heat treat batch ready. I cut out a second spring and blade for a slip joint because I'll probably mess at least one up.

The folders and the blade on the right are 1084 and the one on the left is 1095, only because I didn't have any 1.5"x 3/32" 1084.

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I had to put a second coat of dye on the sheath from yesterday, so no real progress on that one today.

I'm going to need a twin to the sheath I'm working on plus 2-3 others. I'm probably going to get a lot of that done while I'm heat treating these blades(hopefully this weekend.

I've been asked for a bread knife by a couple of people, so I'm planning on getting one drawn up -ish. I'm thinking about trying an offset design. I need to study up on serrations as well.

Nice! Getting the back spring dialed in is half the fun of slipjoints. Let me know if you have any questions when you get to that point. I'm looking forward to see how they turn out.

+1

I'll probably come up with all kinds of questions.

I'm guessing that it's probably a decent idea to leave some extra meat on the parts of the spring that contact the blade?

Always glad to answer any that come up.

Yes a little on the bottom edge of the spring for cleaning up but mostly you'll be taking it off back of the blade tang and the bottom of the tang in the kick area so leave some there. You'll also take a bunch off the spine of the spring and that curved relief inside the spring to dial in the spring strength.

If you haven't yet, don't drill the middle pin hole in the scales until you are ready to tension the spring. Just drill the pivot hole and the rear spring hole.

One note - Do not attempt to check the action of the blade until you've got all 3 positions dialed in pretty close and the spring near final dimensions or you risk breaking something because the spring will be way too strong until some meat is taken off.


Here are my steps to dialing in the function of the slip joint:

It's best if there are 2 points of contact between the blade and spring in each position. If there is one point, then the blade will wobble and not feel locked up.

After heat treat and you've and got the parts roughed in you'll want to dial in the length of the spring first which will set the fully open position. The other 2 positions are all done in relation to the fully open position. Install the spring and blade with the rear and pivot pins between your scales. No need to mess with the center pin yet. Now you can swing the blade open to meet the end of the spring. Slowly adjust the length of the spring by grinding the tip until the blade stops in the position you want for full open, leave a little meat for polishing. I like to grind the tip of the spring back an a very slight angle so the top of the spring is what contacts the back of the blade notch. So my two points of contact are the top of the notch and the back of the tang. Polish up the 3 interfaces; bottom and end of the spring, top of blade, and back of the stop notch on the top of the blade that contacts the end of the spring. From this point forward, don't touch those three surfaces again, they are your reference position.

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Now it's time to adjust the other two positions (closed and half stop) so that the back spring will be flush in all 3 positions. One of the easiest ways I've seen to do this is to put some layout fluid on the side of the spring and then install it back in the open position with the scale or liner. Take a scribe and scratch a line in the layout fluid along the spine of the liner or scale. This line now represents the spring position in the fully open condition and you can use that as a reference when dialing in the other positions.

Adjust the close position first. Close the knife, just push the spring into the knife with your hand for now. See how far off the line on the spring is from being flush with the scale. This represents how much material you need to take off the "kick" of the blade. The kick should contact the spring in two places when it's closed, that helps make it stable. This is why many kicks have a curve to them. They contact the spring at the tip and the other end but not in the curved middle. Taking material off the tip of the kick will make the blade sit lower in the handle when it closes. Taking more off the back will move the tip out a bit when close. Taking the same material off both the tip and the end will lower the spring but not change how far the blade closes into the handle. Very slowly take material off each location until the line you scribed on your spring is flush with the back of the handle and the blade is closed in the position you want. This is one place you can trash a knife so take your time. If you overshoot the closed position, you may end up with a floppy knife.

Once the closed and open positions are dialed in, you can dial in the half stop position. Use the same technique of referencing the scribe line on the spring to see how much to take off of the rear of the tang. It's relatively easy and the only really problem here would be if you over or under shoot your scribed line, you'll have a spring that is not totally flush in the half stop position. Not the end of the world, you'd still have a perfectly usable knife. I'll grind a small concave section back there so only the corners are contacting the bottom of the spring.

Polish all of the surfaces that hit the spring now. You can slightly radius the two corners, but don't overdo it. Basically just knock the sharp corners off. The bigger the radius on the tang corner, the mushier the action will be.

At this point you can set your spring tension. It will change your 3 positions just slightly but they can be dialed in a bit more to compensate later. To set the spring tension, assemble the spring, one liner, blade, and pivot and rear pins. Get your spring and blade into the open position, then scribe a small line inside the liner along the bottom of the spring near where the center pin hole is located. Take the blade and pivot pin out and hold the spring, liner, and rear pin together. Rotate the spring down about the pivot pin so that the bottom of the spring is now roughly 0.020-0.030" lower than the mark you just made in the liner. Hold the spring there, take a transfer punch and put it through the center pin hole in the spring. You're just moving the middle pin hole down 0.020-0.030" from it's natural resting position, this provides the pre-load on the spring. Punch the hole location and drill it for your pin. sandwich the other liner with the pivot and rear pins in place and use the first liner as a drill guide to drill the second liner to match.

Now assemble the blade, liners, rear and front pins, no middle pin yet. Grind the spine of the spring down to just above flush with the back of the handle (say .040-0.050" since the spring tension will pull the spring down some). Cool the spring frequently because it's easy to kill a spring by overheating now that it's getting thinner.

Once you've ground the spine of the spring you can insert the center pin. I do this with some soft plastic jaws on my bench vise. Put in the front and rear pins and set the knife in the open position. Now clamp the knife in the vise with the spine of the spring against one jaw and the open bottom of the handle against the other jaw. You're just trying to compress the back spring some. Don't clamp down too hard, I've bent handles getting too aggressive at this stage. Take a section of pin stock roughly 1" long and grind a nice taper on one end. Put that end in the center hole and drive it through the handle, that taper will pull the spring into position. Don't force it.

Take the knife out of the vise, it should now have the spring fully loaded. Gently try to close it, if it's super hard, don't force it. Take it apart and start grinding away at that concave section on the bottom of the spring in your template. Take some material away, test the fit, take more material, test. Repeat until you're pretty happy with the action. Make sure the joint is clean and maybe put some oil in there when testing the action to get the best feel for it. Err on the side of being too stiff at this point, you can keep reducing it over time up until just before you peen the knife for the last time.

I'll usually keep a knife at this stage for a while and put some temporary pins in it. Sit around and fiddle with it for a while to see if you want to make it looser.


Ok I'll stop there for now. Once you want to move past that point, let me know. Ther are some tricks and pitfalls when grinding the handle that you might want to consider. I also have some tricks for peening.

damn

damn

It's a process

The ones that come off my CNC don't need nearly as much fitting up as that's already been baked into the design. The one-offs do need a lot of fitting.

well if anyone is up to it, it's DFARM. he's pretty handy.

I have no doubt, his other knives are great.

Damn , son. Thanks a lot!  I appreciate the info.

I wouldn't have thought about setting the spring tension that way. What I had in mind most likely wouldn't have worked very well. Lol

Absolutely. Glad to help. The spring tension and setting the 3 positions was probably the hardest thing for me to wrap my head around when starting slipjoints. The are kindof addictive once you get a process and can crank a few out.

This one is going to be pretty cool.

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This one is in 3/32" 1095.

The " real" one is going to be in aeb-l.

I've got all the folder parts and the two fixed blades that I wanted to get heat treated today austenitized(hardened) and I'm waiting for the oven to come down to 675° to temper the back springs, then again to 350° to temper all the blades.

I'm getting some leather work done while I wait.

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Weekend wrap up:
Folder springs are tempered. I'm not sure the hardness, since my chisels only go down to 58. They were ~64 as quenched, then I tempered at 675.  They were dark blue when they came out.

Folder blades and fixed blades are tempered to 61-62 hrc. The sheep's foot looking one has a bit of a warp that I'll have to address but the others are ready to start grinding.

I had to make a new sheath because the one that I had started ended up being terrible. The one in the picture is drying from wet forming. It needs it's edge finished and the finish put on. The knife that goes in it is all the way finished, unless I decide to put a lanyard on it.

The sheath parts that are there are to make a sheath for my copy of the knife in the pic.

Change of plans. I wanted to keep my first attempt simple, so it'll be carbon fiber with no liners and I've got mild steel pins in it for now but I think I'll see if I can get some stainless pin stock before I stick it together permanently.

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You did that on purpose because I called dibs on your first folder and you know I hate CF so I would automatically reject it and you could keep it.

There's basically a zero percent chance of my first copy of anything being good enough to let someone else have. Lol

convenient lies

This thing is pretty cool already and it's not even really a knife yet. Lol

I'm going to play with it for a bit but I think I'll grind some more out of the spring to lighten it up a little more.

I'm glad you are getting excited about it. Folders are where its at.

They're certainly better for actual daily carry. I've tried to make a small fixed blade work but it's just not as convenient as a folder.

The mechanical aspect is also pretty interesting.

@Reubjames , I'm at this point. I think I'm going to grind bevels on the blade after I get my reliefs finished around the pivot in the scales.

I saw that some people do that instead of putting washers in the pivot, so I decided to do that. It's not pretty because it's like trying to draw with an etch-a-sketch but at least it's inside the knife.lol. The carbon fiber scratches the blade pretty badly so I wanted to do something to keep the ricasso area from getting beat up.


As a general update, I'm working on leather for the last two fixed blades I finished for myself but it's been kicking my butt. I had a disagreement with my sewing machine yesterday, so I'm sewing the next sheath by hand to avoid ruining another one.  I also haven't had a ton of time between work, chores around the place and generally not feeling 100%.

I don't know how you have time for any of this given what you have going on.

I have to do it to stay sane and somewhat happy.

We're not actually doing any construction for the house yet, so there's just a lot of stuff to do around the place, dealing with stuff that was left here by the previous owner and general cleanup chores that go along with having a place in the woods(that haven't been maintained for a few years because the dude was old).

@DFARM Yeah some guys like washers, some like relieved liners, and some guys will actually grind a small, raised boss portion (like a built-in washer) into the blade on each side of the tang. I don't know how the heck they do that but it looks good and works well. I've gone back and forth between the washers and relieved liners. Both have their pros and cons. I do like relieved liners a bit more because that means you can keep your blade and spring the same exact thickness. Without a proper surface grinder, it's tough to take exactly 0.010" off the thickness of the blade. I've done it on my "surface grinder" attachment but there was a lot of back and forth and took a long time to nail it. Recently I've been relieving the liners on the mill which is significantly faster.

For grinding bevels, it's hard to hang onto the short blade on a folder. I've done a couple tricks that help. Basically, you just want to come up with some way to add a temporary handle so you can grind the bevels just like you would on a fixed blade that has a full tang. I first used just a scrap piece of wood and used a small clamp (I used a tiny kant-twist) to clamp the tang of the blade to the end of the wood. This isn't a bad way to go but the clamp does tend to get in the way. I made a handful using that method.

After getting tired of the clamp getting in the way, I made a small dedicated clamp using a couple short pieces of AEB-L heat treated and tempered to a spring temper. A couple threaded holes let me clamp it down on the tang of the blade and provide a nice handle to hold onto while grinding. The only important holes in this are the ones with the screws in them. The other holes were in the wrong spot . Flathead screw in the front and then a set screw in the rear to tighten things up.
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When it comes to grinding the handle, I leave the scales flat on each outside face, then run some pins through so you grind as a pair and that the spine is perpendicular to the liners. Set your work rest perpendicular to the belt and grind with the belt runing the length of the knife. A horizontal grinder would be very handy here if yours pivots so you can rest the handle on the work table and have the belt running down the length of the knife. When you grind on the spine of the handle, make sure the spring and blade are installed in the open position so they all get ground flush with each other. For the inside of the handle, I take the blade and spring out so they don't get in the way.

Once you're satisfied with the grind on the permitter of the handle and blade, you can then start to contour the outer face of the handle scales however you like. I typically scribe a line around the permitter of the scale say 0.090" or 0.1" above the inner face of the liner. This is where I stop my contouring and leave the flat face of the liner, scale, and spring. It's pretty much like contouring any other handle you've done. It's mostly aesthetic at this point. I tend to just round mine over leaving a clean arc from each of the guidelines I scribed in up to the max thickness of the scale. My scales are usually end up around 0.175" thick or so. Of course thinner or thicker is all personal preference here.

From there it's just finish work and then peening the pins. Install a shield if you're going to. Sand the handles down to almost finished grit. Finish the blade. Polish any internal parts you want to polish. Then peen the pins.

Peening is tricky, the main thing is to take your time and go slow, keeping an eye out for any issues as you go.

The pivot pin is the hardest to get right. Just peen a few hits, test the action, peen some more, test the action. If you overshoot it, you'll have to drill the pin out and start that pin over. Just go slow with it. Ideally you'll get the pin tightened up so that there is no side-to-side blade play but the action is still smooth without any binding through the full range of motion. It's a very narrow window.

The other two pins are easier but they do have some pitfalls to avoid. If the pin hole is really close to some thin areas in the handle material, you can crack the handle by over peening the pin. If the pin is too long out of the handle, you can accidentally bend it over and that will be a mess to clean up.

Here is a good video that Meads put up a few years ago:

I'll give the video a look later. Thanks again.

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I just held the blade in the clamp, then in my file guide to grind the plunges(which didn't work out like I wanted but they look ok)

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Back spring is flush in all 3 positions

I still need to contour the scales and mark the blade.  Before I think about putting it together.

I know I probably shouldn't worry about it for this one but I kind of want a nail nick of some kind. Enough of the blade sticks out that I can open it but a little more grip would be nice. I might play around with a Dremel cutoff wheel in my drill press and the blade held in my X/Y vise.  I don't think I trust myself to try free handing it.

Looking good!

Nail nicks are tricky. I've tried a half dozen ways to make them. My first slipjoint didn't have one and I just relied on gripping the blade to open it like you've suggested.

Before I started cutting my nail nicks with a fly cutter on the mill, I had a setup where I mounted my dremel in a plate with a grinding disc. Tapped a hole that fit the threads on the nose of the dremel tool. Then clamped my blade to a 123 block at the right height for the nick. Marked the nick on the blade, then slowly slid it up to the grinding disc and worked it back and forth until the nick looked about how I wanted. The grinding disc results in a more rounded nick but certainly serviceable. Sounds like your XY table should help line things up and it'll be similar to the method I used with the dremel.

Some guys punch them in hot with a custom ground chisel but I never had any luck with that method.

I'm done with this one for now. I'll probably mess around with a different style of sheath at some point but this one works ok for now.

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I've got the bevels about 90% ground on the 4" fixed blade that I heat treated in the same batch as my folder parts. I'm hoping to get it ready to glue handles on tomorrow.

I'm expecting some stainless pin stock for the folder tomorrow, All that's left before piening it together is to mark the blade so I'm hoping to get that finished this weekend.

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Some quick first thoughts about this thing.

It's pretty awesome to have made my own pocket knife. My small fixed blades are cool but they'll never be as convenient to carry as a folder.

I'm not the biggest fan of this pattern. I know it's the nature of the folding knife beast but this one seems like the handle is twice as long as the blade when it's open. I also don't care for the sharp corner of the blade that sticks out of the handle.

I'm going to build the other blade and spring that I made but I'll probably find a different pattern for the next one.

Thanks again ReubJames for all the help. I'm positive that you saved me a bunch of failures and frustration.

Setting folders aside for the moment... I'll definitely get back to them though.

Getting started on a prep knife in AEB-L and working on another new fixed blade pattern.

This new one is in 3/32" 1095. 8.5" overall with a 3.75" blade.

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Bottom one looks like a good utility knife.

It should be a lot more handy than the last fixed blade was.

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Got a batch of blades in AEB-L hardened while I was working on one of the chicken tractors today.

Now I have to try to find spring temper temps for AEB-L. Lol

The bottom two are kind of oddballs. They're 1/8" thick. I'm thinking about making them into something geared towards self defense, though I have no idea what I'm doing in that regard, so they'll probably just end up stabby, possibly double edged and who knows what else. Lol

Glad to help! It looks great to me. Sorry I've been slow to respond, a lot going on these days.

When looking for new patterns, Chris Crawford has a ton of free files on his website if you haven't seen them.
https://chriscrawfordknives.com/patterns/

The sharp corners on the back of the blade are irritating for sure. A lot of patterns have that and I think it's a good place for improvement. I've taken a bunch of time working on my patterns to make sure those sit flush with the handle when close. It's a balancing act for sure to get them smooth. There is only so much you can move the geometry around and still have a functional and proportional knife. Something to consider on the next one.

Let's see if this works. Getting all the pieces to stay put with the epoxy making them slippery is a bit of a challenge.

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Got the flats cleaned up on this dude as well.

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I ran out of wire for chicken tractor V2.0 so I got a chance to work on knives for a bit.

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