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Slipjoint making?
- Thread starter Kosa_PL
- Start date
I like that spring shape a lot better but you have the tip of the blade resting on the spring now. Going to knock the edge off or even chip the tip when it closes if you don't give it some room. I did a little doctoring on your picture here...
You'll want to leave some extra material on your spring where I colored it green so you'll have a preload when the knife is open or closed. You'll also probably end up grinding a fair amount out of the orange area but I couldn't say how much. You'll have to temporarily pin it together and feel how stiff it is, then grind accordingly until you like it. And you'll want to trim the spring back something like I have drawn in red on the left side of the picture to give your blade some clearance.
If you'll take an existing slipjoint and gently push the blade down into the handle a bit, you'll see that it doesn't take much to push the blade beyond the closed position. When it snaps closed, the momentum does the same thing. How much depends on the weight of the blade, stiffness of the spring, length of the kick, amount of spring travel, how freely the blade moves without spring tension etc... in other words a lot of stuff going on there so you need to give it all some room to work.
Alternatively, you could do what I've done on some lockbacks and put in a stop pin where the choil will come to rest. That also simplifies some other stuff allowing you to get your spring flush in the open and closed positions a whole bunch easier too.
You'll want to leave some extra material on your spring where I colored it green so you'll have a preload when the knife is open or closed. You'll also probably end up grinding a fair amount out of the orange area but I couldn't say how much. You'll have to temporarily pin it together and feel how stiff it is, then grind accordingly until you like it. And you'll want to trim the spring back something like I have drawn in red on the left side of the picture to give your blade some clearance.
If you'll take an existing slipjoint and gently push the blade down into the handle a bit, you'll see that it doesn't take much to push the blade beyond the closed position. When it snaps closed, the momentum does the same thing. How much depends on the weight of the blade, stiffness of the spring, length of the kick, amount of spring travel, how freely the blade moves without spring tension etc... in other words a lot of stuff going on there so you need to give it all some room to work.
Alternatively, you could do what I've done on some lockbacks and put in a stop pin where the choil will come to rest. That also simplifies some other stuff allowing you to get your spring flush in the open and closed positions a whole bunch easier too.
i like it.
TW said it all, leave your kick bigger to tune in the last adjustments, you will take up and apart million times so you will know if the back of the spring would need to be skimmed to allow inertia clearance and you will have easy tuning if necessary.
Leave extra metal above and in front of the spring and on the blade spine...you'll grind tham all toghether flush.
It seems it's gonna be a very nice build...i like your approach and your knives very much.
Another note (but i'm sure you know already): the front of the spring and the runup corner of the tang shouldn't be square, but slanted a bit over each other at the point of contact, to close the spine.
When in tension the spring will open that seam if square (very well explained and depicted in Steve Culver's tutorial)
TW said it all, leave your kick bigger to tune in the last adjustments, you will take up and apart million times so you will know if the back of the spring would need to be skimmed to allow inertia clearance and you will have easy tuning if necessary.
Leave extra metal above and in front of the spring and on the blade spine...you'll grind tham all toghether flush.
It seems it's gonna be a very nice build...i like your approach and your knives very much.
Another note (but i'm sure you know already): the front of the spring and the runup corner of the tang shouldn't be square, but slanted a bit over each other at the point of contact, to close the spine.
When in tension the spring will open that seam if square (very well explained and depicted in Steve Culver's tutorial)
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http://www.culverart.com/Slip-Joint Folder Designing.pdf
Steve Culver's tutorial, if you didn't read it yet!!!
Steve Culver's tutorial, if you didn't read it yet!!!
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Any material will do, but be sure to use matching material for pivot/bolster.
I started wrong trying to match 420 bolster with 303 pin... double error: 1) they don't match in color; 2) the 30x serie exibits a marked work hardening, which is against nice peening.
If you could get aisi 410 liners, bolster and pins you'll be very happy with how things would go, but also 416 is not that bad
I started wrong trying to match 420 bolster with 303 pin... double error: 1) they don't match in color; 2) the 30x serie exibits a marked work hardening, which is against nice peening.
If you could get aisi 410 liners, bolster and pins you'll be very happy with how things would go, but also 416 is not that bad
- Joined
- Aug 25, 2013
- Messages
- 1,220
Ok one of tools greatly welcome for making any folder knives obtained 
Surface grinder wit hydraulic autofeed. (Big bad ugly fat 1.200kg 1,5kW spindle power, Jung F50R - variable speed)
But ot get this I needed to sell... Milling machine.
As also I got a nice stock of steel, I think what to do...
Did somebody know how to temper AEB-L for a spring ?
Or better will be to use steel 4H13 (1.4034) for a spring and AEB-L / Elmax etc. for a blade ?
Next milling machine will be probably a Optimum Opti BF20 L + rotary table etc.
Also I think to make a bigger design what will be good to make with classic pivot and fasteners + screws instead of pins for spring.
Surface grinder wit hydraulic autofeed. (Big bad ugly fat 1.200kg 1,5kW spindle power, Jung F50R - variable speed)
But ot get this I needed to sell... Milling machine.
As also I got a nice stock of steel, I think what to do...
Did somebody know how to temper AEB-L for a spring ?
Or better will be to use steel 4H13 (1.4034) for a spring and AEB-L / Elmax etc. for a blade ?
Next milling machine will be probably a Optimum Opti BF20 L + rotary table etc.
Also I think to make a bigger design what will be good to make with classic pivot and fasteners + screws instead of pins for spring.
