Jump to content
Brian Dougherty

Culver Inspired (Copied) Slipjoint

Recommended Posts

I made a bit more progress this weekend.  I got the blade and spring heat treated without any drama.  I wasn't sure what to temper the spring to, but I decide to leave it at the same temper as the blade.  (Both were tempered at 400F)

 I forgot to grind in a nail nick before heat treating, so now I'll have to do that the hard way. :rolleyes:

Here is a very exciting pic of the parts during the first temper cycle.  The crud is what is left of the anti-scale compound.

 IMG_20190504_135105311.jpg

I didn't take any pics while I was adjusting the tip of the spring and the blade tang.  To paraphrase Culver, you grind the spring tip back until the blade tip is just a bit lower than where you want it in the open position.  Then you adjust the 'kick" and the back corners of the tang to adjust the closed and half-lock positions.

Once all of that is roughly adjusted, it is time to drill the second spring hole in the liners thus setting the springs position forever.  Culver suggests preloading the spring by 0.015" to 0.030".  I went with 0.020".  to do this, I clamped the spring in place with the blade open, and measured it's position from the bottom of the liner.  Then I removed the blade, and re-clamped the spring in place 0.020" closer to the edge.

Measuring the spring position:

IMG_20190505_171057849.jpg

I goofed here a little.  The neutral location of the spring in the half-locked position was actually about 0.010" closer to the edge than it was in the full open position.  The result is that the half-locked position doesn't feel as positive.

Here are a couple of shots showing the guts.  The design has the blade contact the spring in only two points.  The gap in the corner creates a space for pocket lint.

IMG_20190505_190030288_HDR.jpg

IMG_20190505_190023388_HDR.jpg

Here is another goof-up:  I just free hand ground the bevels in, and didn't scribe a center-line along the edge of the blade.  The end result is I ground it off-center, and the tip isn't centered between the liners.  Isn't keeping the blade centered in the liners supposed to be job one with a folder?  Oh-well, live and learn...

IMG_20190505_190259700.jpg

Here is a short video showing the opening and closing action.  I'm pretty happy with the locks and the tension at this point.

Share this post


Link to post
Share on other sites

Brian,

 

When you get the blade a little off center you can cheat a little if you want.  Force the blade closed with some feeler gauges on the side which is  the tightest to slightly bend the liners to compensate.    It's not ideal but beats having an off center blade.

  • Thanks 1

Share this post


Link to post
Share on other sites

Thanks Gary.  It looks like I can twist the entire assembly very slightly to to get it centered.  At least I can flex it there with my hands.  We'll see if I can get it to stay there :)

Share this post


Link to post
Share on other sites

I got the nail nick ground in this evening.  I used a grinding stone with a dome shape in a little dremel router table.

IMG_20190508_180910784.jpg

I thought putting the nail nick out towards the tip would be more practical as it gives you better leverage when opening.  However, it looks kind of goofy there, so I'm wishing I centered it more.

IMG_20190508_191607582.jpg

I also worked to center the blade up better in the liners.  I used a pretty shady process for this.  I clamped the blade to a straight bar, and then shimmed the tip over slightly and put the whole works back into the tempering oven. 

IMG_20190508_191602166.jpg

The bolsters are about twice as thick as I intend to leave them.  but I'll mill or grind them down to thickness once I figure out the scale material. 

Share this post


Link to post
Share on other sites
Posted (edited)

The blade looks much better.  The position of the nail nick doesn't  bother me.  The  sharp square edge of the blade at the front bolster area does.  Some don't mind it.  I have a "thing" about the sharp square corner being exposed.;)  I like to see it covered by the front bolsters.

 

Edited by Gary Mulkey
  • Thanks 1

Share this post


Link to post
Share on other sites

I agree about the exposed corner.  Culver addresses this in his book.  I copied a bit of it here so others can see the trade-off for covering up the joint.

IMG_20190508_211300631.jpg

In the end I decided the exposed joint was my preference over the look of the open blade with a sunk joint.  That is a very function follows form approach which isn't usually my nature.  I believe this trade-off is one of the limitations with the slip joint design, but I haven't spent any time thinking about how to design around it.  (I've pretty much just been blindly following Culver's pattern)

  • Like 1
  • Thanks 1

Share this post


Link to post
Share on other sites

Great progress. I would temper the spring a little softer. 500-600 for springs

  • Thanks 1

Share this post


Link to post
Share on other sites
Posted (edited)
1 hour ago, Joshua States said:

... I would temper the spring a little softer. 500-600 for springs

Thanks, I'll prob throw it back in for another cycle then.  I couldn't find any reference on that.

Edited by Brian Dougherty

Share this post


Link to post
Share on other sites

Today was a good day :)

I decided to use a mill to thin down the bolsters.  The original stock I used was 0.250" thick, which I knew was way too much, but I was worried 1/8" wasn't enough, and I didn't have anything in between.  I ended up cutting them down to 0.150", but  1/8" would ahve been fine too.

IMG_20190511_080354514.jpg

They are a much more appropriate size now...

IMG_20190511_094302462.jpg

Share this post


Link to post
Share on other sites
Posted (edited)

Next I thinned down some antler scales I had and roughly fitted them so I could epoxy them in place.

IMG_20190511_100357217.jpg

 

IMG_20190511_100401202.jpg

 

I did chores for a few hours, until the epoxy cured, and then roughed off most of the excess material.

IMG_20190511_160146544_HDR.jpg

Each liner has two holes for rivets to hold the scales on.  I beveled the inside of the holes with a center drill to create a space for the rivet head.

IMG_20190511_183612679.jpg

Then hammered a head into some 1/16" brass rod, cut it off a little longer than necessary...

IMG_20190511_183658981.jpg

...and peened it over.  @Jerrod Miller your little anvils work well for this!

IMG_20190511_185700758.jpg

The first couple were a little rough, but I got the hang of it by the end.

IMG_20190511_191101528_HDR.jpg

Edited by Brian Dougherty
  • Like 1

Share this post


Link to post
Share on other sites

Then I spent some time filing and sanding the bolsters and scales to shape.  I've got a little more shaping to do, but I've sanded through the side of my thumb, and got tired of bleeding all over the knife.  This is where I'll stop for the night.

IMG_20190511_193646384.jpg

IMG_20190511_193654529.jpg

IMG_20190511_194542890.jpg

  • Like 4

Share this post


Link to post
Share on other sites

My goodness, you are doing a jam up job with this Brian, my hats off to you!! I did a slip joint a few years ago, also saved S. Culver’s instructions via web but haven’t gone back to try another. Great job!

Gary LT

  • Thanks 1

Share this post


Link to post
Share on other sites
Posted (edited)

Reminds me of the case knives trapper.  Looking good!

 

 

This reminds me, I still need to decide if I’m going to do a fixed or a folder for KITH. 

Edited by Conner Michaux
  • Thanks 1

Share this post


Link to post
Share on other sites

Impressive!

  • Thanks 1

Share this post


Link to post
Share on other sites

Gorgeous Brian!  I've really enjoyed watching this one come together.

  • Thanks 1

Share this post


Link to post
Share on other sites

I spent some time doing finish work today.  This blade is quite a bit smaller than what I am used to making.  It certainly takes less time to sand than a chef's knife.

IMG_20190512_131653229.jpg

I still need to do some final sanding and polishing on the bolsters, but the parts are all getting pretty close.

IMG_20190512_175136793.jpg

There is no way to create a perfectly smooth transition from the liners to the spring without sanding the back of the knife after final assembly.  I wanted the pattern welded spring to be etched, so sanding after assembly is a no go. 

Even with all the pins as a perfect fit, there would most likely be enough of a ridge to catch a nail after final assembly which I find irritating so I decided to put a slight bevel along the back edges of the spring and the inside of the liners to create an intentional shadow line.  I think it worked out pretty well.

IMG_20190512_173725243.jpg

Here are a couple more shots.  I need to get some 3/32" brass stock to make the final assembly pins.  I also need to taper the main pin holes slightly so I can peen the main pin.

IMG_20190512_173746846.jpg

IMG_20190512_173750954.jpg

  • Like 4

Share this post


Link to post
Share on other sites

That is a beauty, and an engineering marvel!

  • Thanks 1

Share this post


Link to post
Share on other sites

Amazing Brian, one day when I'm all grown up I'll try that!

  • Thanks 1

Share this post


Link to post
Share on other sites

Ok guys, here is where those of you who know what you are doing get to shake your head at me.  It's time to peen the final pins, and close this thing up for good.

I decided to use nickle silver for the bolsters.  However, the blade will pivot directly on the main pin on this knife, so I wanted to use a hardened steel dowel pin that would hold up well.  This means that the pin will never truly disappear in the bolster as it is a different material and a different color.

Since the pin will be visible, my strategy was to make the pin look as clean and uniform as possible.  I started out by using a tapered reamer to lightly bevel the pin holes from the outside.  This is a reamer made for tapered pin holes which has ~1-deg taper.  This will allow the pin to swell into the bevel, and lock the pin in place.

Here is a practice run I did in a piece of brass.  It was promising, but there was a bit of mushrooming around the edge of the pin that I would have to overcome.

  IMG_20190514_192225746.jpg

 

I used a marker to blacken the inside of the holes so I could see how far I had run the reamer in.  I left the innermost part of the hole the original diameter.

IMG_20190516_180021872.jpg

Then I ground the pin to be 0.200" longer than the width between the bolsters, and beveled the ends so that the straight section was the width of the bolsters.  I figured this would allow me to drive the center of the pin down and swell it out from the inside and avoid the mushrooming.

I also tempered the ends to soften them while trying to leave the center hardened.  I just used a torch, and ran the colors in toward the center.  (Sorry Jerrod :) )

IMG_20190516_181833943.jpg

Here is the pin in place ready to be peened.  This is where I started worrying about my hammer control.  It felt wrong to start hammering on something I had spent so much time to make.

IMG_20190516_182048770.jpg

  • Like 1

Share this post


Link to post
Share on other sites

So out to the anvil I went (during a tornado warning no less).  My test attempt taught me that my small ball-peen was not heavy enough really get the pin to start deforming, so I picked up my 2-lb smithing hammer and went to town.

This was very much a death by 1000 small blows approach, and I found at first I could only hit it about 6 times before I would have to flip it over and hit the other side.  Otherwise the pin would start to move away from center.  However, once the pin started to lock in place I could rap on it a a hundred times or so before flipping it over.

Here it is after a few minutes of hammering...

IMG_20190516_184715957.jpg

...and I managed to do this without marring up the bolsters too much.

IMG_20190516_184720158.jpg

In the end, it really went pretty well.  The action of the knife tightened up slightly, but not as much as I was afraid it would.

I still need to do the finish sanding, but here is the pin all cleaned up.  I had put the final brass pins in at this point as well.

IMG_20190516_193325018.jpg

IMG_20190516_193335649.jpg

I'm getting close to finishing it up.  I have to admit that I am going to have a hard time letting this one go.

  • Like 2

Share this post


Link to post
Share on other sites
25 minutes ago, Brian Dougherty said:

Sorry Jerrod :) 

This did not go un-noticed.  I'm judging you...harshly.  This whole package is junk now.  You'd better keep it for yourself, as it would be unfair to another smith to have this abomination forced upon them.  :ph34r:

  • Like 1
  • Haha 4

Share this post


Link to post
Share on other sites

Damn that's nice.  I think I'd have a hard time parting with it as well.  Thanks for taking us along on the journey for this one.  A slipjoint is on my list, and I'm sure I'll be coming back to this thread for reference.

  • Thanks 1

Share this post


Link to post
Share on other sites

Man That Sure is nice.  With the kith Date a mere 4 months away, I better get started.   You are setting the bar High there.

  • Thanks 1

Share this post


Link to post
Share on other sites

I need to start too, but I have learned not to use a gorgeous bit of stag for my scales.  I would have a hard time letting it go too!  I hope mine comes out at least a quarter as nice.

  • Thanks 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...