Anyone own a flush spring/joint knife?

[Ron Sabbagh]

Okay flush joints (flush backspring) are not new per se but new to me. I’ve just recently heard of their existence and was wondering what the action was like compared to a traditional slip joint.

not much information on the interwebs about them except it takes great skill to achieve the desired goal ....

 

[Old Engineer]

I am not sure what you are wanting the Backspring to be Flush to but I expect that you are meaning Flush at the end with the Blade and Bolsters . The only ones that I am aware of with that are Taylors Eye Witness Barlows of which I have 2 . The GEC #73's get close to accomplishing that but neither of my 3 do . There are probably some more , but I do not know who .
Taylors Eye Witness Barlows are 2 on the right . Gec 73 on the left .


Edited to add : Action is pretty stiff because of the square ends of the blades . Desirability of that is certainly up for debate .
I hope that this helps you out my friend .

Harry

 

[Arathol]

No difference, just constructed properly...

 

[rockman0]

For comparison the one on the right is a flush and square joint, left is a flush joint. Both of these are Sheffield knives, strong pulls and hard snaps but of course other Sheffield knives without a flush joint have the strong pulls and hard snaps, I can't tell a difference in the actions.

 

[blademan 13]

The classic Remington 1123 & 1173’s had this feature as did the Camillus produced reproductions. Of course as Harry mentioned, the GEC 23’s & 73’s feature it as well. The sharp tang edge can take a little more effort to get moving than a regular half stop knife with its tang edge rounded but action is just as dependent on spring strength.

 

[kamagong]

Those are also called clean and square joints. GEC's #23 and #73 patterns have them. As you noted, they are a display of a cutler's skill.

Here is a knifemaker's thought on the subject.

I hope everyone can appreciate how difficult it is to make the bolsters, tang end, AND SPRING all flush AND make the back of the spring flush with the liners in all three positions . I'm happy if I can get the tang end flush with the bolsters and back spring flush in all three positions. (See mine below, same knife in avatar) Making the spring end flush as well is HARD TO DO.

Making a knife with half-stops has a PITA Factor of of 10, whereas a cam-end knife is a 7. Flush the joint and the PITA Factor jumps to a 12 or 13...just sayin (and that's on a single blade knife )

....but I still like em.

Old knives ROCK! They were made to be used not to win any dang contests! The flush joints on the knives in the 3rd image are SCARY FLUSH! This is the kind of thing that truely inspires a great knifemaker.

That knife on the left is awesome! The bolsters, liners, blade, and spring are all flush. On my #73, the spring falls just short. It boggles the mind that the knife above was made by a man who was paid less than minimum wage (when adjusted for inflation). Especially when you consider that there are very few makers working today who can make a knife to the same high standard.
​

 

[Ron Sabbagh]

Thank you all. I am still learning about this. Yes, it would seem that there would be an extra level of skill required to pull these off effectively. I find it very interesting.

When I mentioned that the backspring is flush....I was told that some flush joints operate where the backspring stays flush to the liners in all positions - instead or rising and falling in a typical slip joint.

 

[Old Engineer]

I believe that they mean that everything is flush at Close , Half Stop , and Open Postitions . The Spring has to flex and move or you will not get the Blade Open .

Harry

 

[Ron Sabbagh]

https://blademag.com/blog/a-revolution-in-slip-joint-construction

 

[Will Power]

Square-End construction, as seen on certain old Sheffields, the GEC 73 (their first and in some ways, defining knife) the 23, I have a French knife with it. Less dirt gets in I suppose oiling a bit trickier too, heavy pull factor, sturdy construction. But got to say, prefer no half-stop cam tang

 

[blademan 13]

The well revered Remington on left compared to a modern GEC #23.

You can see where the wore tang edges on the Remington have disrupted the tight fit and also softened the pull slightly with the lower blade (drop point) having softer pull than the upper blade.

 

[black mamba]

. . . the backspring stays flush to the liners in all positions - instead or rising and falling in a typical slip joint.

I remember talking to Tom Ferry about his design at the BLADE Show back in 2012. An ingenious design, but the knives I saw with this feature were all slightly deeper (well opening to spring) than standard slipjoints. Just something to consider, not necessarily a negative.

 

[Ron Sabbagh]

The only custom flush joints I’ve seen offered are from Tony & Reese Bose and Tom Ploppert, which is why I’m thinking the skill level to achieve the desired goal is off the charts.


Tony Bose backpocket with flush joint

View attachment 1326255

 

[Misplaced Hillbilly]

https://blademag.com/blog/a-revolution-in-slip-joint-construction

The way I read this and interpret it is that the "backbar" as they refer to it is split,with one of the legs of the split being the actual spring that performs as a backspring should. In this manner all this is nothing more than a hidden internal backspring. Worries about the movement of the backspring causes wear that loosens the knife somehow is frankly silly to me. I have many knives that are decades old,and a couple for sure that are over 100 years old that are still tight. Creating a non moving backspring (actually the spring moves you just cant see it)is an answer to a problem that doesn't exist if done for the sake of wear. If done solely for aesthetic reasons then its nothing more than a bit of clever engineering and as such would have merit for that alone.

 

[Jeremy Temares]

The classic Remington 1123 & 1173’s had this feature as did the Camillus produced reproductions. Of course as Harry mentioned, the GEC 23’s & 73’s feature it as well. The sharp tang edge can take a little more effort to get moving than a regular half stop knife with its tang edge rounded but action is just as dependent on spring strength.

 

[Ice Tigre]

The only custom flush joints I’ve seen offered are from Tony & Reese Bose and Tom Ploppert, which is why I’m thinking the skill level to achieve the desired goal is off the charts.


Tony Bose backpocket with flush joint

View attachment 1326255

I'd call that one a complete fail... if your going to that much work, and on a full custom that is so much work to begin with, yet don't actually get the spring flush to the tang?

That tapered gap is hideous.
I hate the look and function of this concept to begin with. But if you're doing it, do it right.

 

[willard0341]

To the Op, even gaps on the hood of a car doesn’t make it run better/faster, it is a mark of craftsmanship.

 

[ea42]

https://blademag.com/blog/a-revolution-in-slip-joint-construction

That's an interesting concept but it does involve more parts than a normal slipjoint which means more machining, fitting, etc. Also you need a lot more space to fit all that extra hardware meaning the bolster area has to be much larger. I don't see how it would be an improvement over a design that really has nothing wrong with it to begin with. What happens when you get all kinds of crud down underneath that flyspring? You have too take the whole knife apart where on a regular slipjoint you just rinse and wipe it down.

 

[I'mSoSharp]

I might be missing something here but I don't see the tang & spring being flush with the bolster difficult to achieve (or dare I say, even desirable!).
It's a case of making the bolsters fit the tang/spring not the other way round. Lots of folders could have the bolsters flattened to make them flush with the tang closed if they have a tang with a flat half-stop.
The square tang & spring fitting into a square end bolster is slightly more involved, but the method will still involve shaping the bolsters as the last part of making.
I don't see them as anything special, just a different bolster style like sunken/hidden joints.

Edit. The link above to the "hidden spring" knife is nothing new, look at a Thiers Douk-douk! Also the pictured knife has a very small tang relative to blade size, on the same knife a normal spring would allow a bigger tang. Same design problems as sunken/hidden joints.

 

[Tyson A Wright]

I think the OP is talking about Everflush slipjoints. Designed by Tom Ferry and Mike Vagnino, and I think Kizer makes a few models now. I've seen pictures, but never have never held or used one.

-Tyson