multi blade lockback proto-1

J

Jared Stenoien

Joined
Dec 4, 2005
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here's a picture of it as drawn right now, I plan on making the handle a bit less brick like but this should give you an idea of the general setup of the knife. Any suggestions/criticisms would be very appreciated. The top two are holders for the x-acto razor saw and keyhole saw which can both come in very handy at times. The handle is .5" wide and 4.5" long. Thanks. :)

woodcarver.jpg
 
Your design needs a little revision.

The pivot hole in the backbar needs to be in the center, not near the end,you'll get more mechanical advantage this way.
The Raised pivot hole area looks like it is too high and the blades will hit on them when closed.
The blades look like you have designed them to lock in both the opened and closed positions? I think your hook design for the lockbar is interesting, most makers make them rectangular.

And you didn't leave room for the springs that keep upward pressure on the lockbar.

I guess it's back to the drawing board!
 
A possible variation might be a common center pivot for the lockbars, instead of end to end. You may end up with relatively short blades for a given handle size.
Thanks for showing, Craig
 
ah yes...the springs...I don't know how I missed that lol, but that's why I posted it here! What thickness should the spring be? The reason I made the pivot so far over is that it'll allow me to not have to depress the back as far, but it'll be much stiffer at the same time. Is there a reason this wouldn't work? The reason I want it to lock in the open positions is I was thinking of making it so the pivot is just loose enough that when I depress a lockbar the blade becomes a gravity knife. Thanks everyone for there advice so far. :thumbup:


edit to add: With the currenty lockbar setup, every ounce of force applied to the lever end applies approximately 3 ounces of locking force. What would be a typical strenght needed for good lockup?
 
mrstenoien said:
edit to add: With the currenty lockbar setup, every ounce of force applied to the lever end applies approximately 3 ounces of locking force. What would be a typical strenght needed for good lockup?
Click to expand...

I may be misunderstanding you, but I think you have it backwards. Force applied to the long end of a lever gives a mechanical advantage on the short end. If your spring pushes on the short end, only 1/3 of the force will be applied to the lock area.

Also, I think the rounded shape of the tang that fits against the hook shape of the lockbar will cause problems. It looks to me like it would tend to lift the hook out of engagement rather than lock tightly against it. If I were you, I would make a prototype of the lock out of brass or aluminum to make sure it works.

Good luck with this project. Post plenty of pictures.
 
wow...I'm just having flatulence of the brain, I think I'll go ahead and put this project aside until after graduation, just too much to think about right now :o and that would make sense about the lockbar not engageing, I'll make a wood template b/c I don't happen to have any brass available.
 
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