Does the spring have to be flush?

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    • pieinthesky wrote:

      Navaja - I don't know if I would do it exactly like that but you definitely have some good ideas there.

      Keeping the spring contact position close to the pivot may be sufficient on its own.

      I think I see a flaw, because it's probably not really a true slipjoint if it relies on a detent.

      Using a flat surfaced spring pretty much ties you up to using similar pressure open & closed.

      As soon as you start playing with shaping the spring to get an advantage when open it becomes a detent, not sure if using a detent is really traditional slipjoint stuff....?

      Radiusing the area between closed & half stop on a normal square tang has the effect of moving the spring closer to the pivot to aid opening. Makes the half stop a little uneven though, all compromises.
    • Can any of the slip joint makers out there confirm something for me?

      When the blade is open, the Kicker (and hence the ricasso) usually sticks out a distance in front of the bolster.

      I want to get rid of this so the cutting edge can come back towards the knife handle and/or I can have a large sharpening notch arrangement.

      This means the kicker would have to be pretty much behind the front edge of the scales.

      I suspect that when the knife is closed, because the kicker is now nearer the front of the knife, it will more easily deflect the spring, so the blade is more likely to slam into the back spring.

      Is this likely? Is this why the kicker is where it is? I have googled and read tutorials but cant find any mention of this anywhere.

      I have made room in the design for a stop pin, (for the closed position only) should this problem arise but wondered if it is really necessary.
    • Thanks Platinum

      I did think of putting the kicker on the spring Shing but you still need the ricasso for the kicker to 'kick'. If you want the blade edge right back to the scales then you still end up with the kicker close to the pivot and therefore I suspect, less effective.

      Just had a look at some Ron Lake folders. No kicker showing but still a large ricasso.
    • If you look at my humble efforts in post #24 here…please-post-24/?pageNo=2& the black bladed knife has the blade sharp right up to the handle, & yes it does mean the kick is shorter so when closed it does offer less resistance to pushing the blade against the spring, having said that it's plenty enough resistance that it isn't going to happen in a pocket.

      That is my favorite as it's maximum edge for the shortest knife, yet only 1 out of 9 people agreed in the poll......... 8|

      A 5mm unsharpened ricasso realistically adds 10mm to the open knife....

      What reason is there for the ricasso? Other than a "longer kick, a place to stop sharpening! or to put a makers mark?

      The post was edited 1 time, last by Navaja: Link added ().

    • pieinthesky wrote:

      mason knives wrote:

      pieinthesky wrote:

      If you could have the spring sitting a mm or so low in the closed position, the knife will be easier to open and could be made to close in a safer more controllable manner. Both without sacrificing security in the open position.
      Could you please elaborate as to why the blade would be easier to open if the spring is lower than the frame. The shape and thickness of the spring really determines the pull, not the shape of the tang so much.The spring should rise by half its width on operation, this ensures a smooth pull and does not put undue strain on the spring.
      When I first designed the PITS folder the spring bar was lower when the knife was closed than when open. The reason being that the spring force needed to hold the blade closed didn't need to be as much as to hold it open. Another advantage of this arrangement was that the effort needed to start the blade opening was much reduced. Obviously when the spring is lower it exerts less pressure on the tang and hence generates less friction.
      I would expect exactly the same to apply to a slipjoint. Maybe the benefit is not significant - until I try it I will not know for sure.

      If I built a slipjoint I would want the blade to drop into the closed position similar to the way lockers do - rather than snapping shut like a trap. It may be possible to do this and keep the spring flush but, having the spring lower in the closed position and carefully shaping the tang would definitely work.

      Hope that makes sense.

      I guess I am putting function before form

      Nothing wrong with function over form in my eyes. Will be interested in seeing what you come up with Mike. :)
    • Navaja wrote:

      What reason is there for the ricasso? Other than a "longer kick, a place to stop sharpening! or to put a makers mark?
      I don't know what the purpose of a ricasso is on most knives. I usually try and make them as small as possible.

      Earthman I have been ogling a few three blade whittlers, so I decided to make my own. Then I thought a single blade might be a better choice for a first slipjoint :)

      I have a good few pie-locks to finish first though, so plenty of time to think about the design.