autos? i am really interested in the idea. dont believe i could make one yet, but i'd like to understand how the different types work. can someone explain (preferably with pictures) how a button activated works compared to a scale activated. and how a coil spring works compared to a leaf type...

thanks

The legal issues associated with selling autos has kept me from spending the time to learn how to make them. But, if you use the blue Search button at the top of the screen to look for 'automatic' or 'switchblade' you should be able to find some useful info ....

found some good info. not much though.

still want to see how a leaf-type auto works. think ive figured out the coil type.

thanks

Check out Chris Crawford's video on autos. I've been meaning to pick up a copy myself and have heard that it is very good.

When I was still in high school I did some repairs on some Italian Stilletto-styled leaf spring autos. I'll try to sketch how the mechanism works and post it tomorrow.

I did a assisted open dr1,I used a coil spring that holds hex keys on a keyring.I found one that fit around the pivotpin,cut it down, and bent the ends to fit notches I cut in the liner and blade pivot hole wall ,then pressfit it in place,For the pivot hole in the blade I used a tapered stone bit in a dremel to open it up ,then small sanding drums untill the spring fit inside,A jewelers saw to cut the notch in the hole.Its strong enough to open the blade on its own so I used a slightly larger bearing in the liner to keep it shut.As far as "leafspring autos" that just refers to a linerlock in addition to the pushbutton,the liner does not open the blade,just locks it open,I think what you mean is a "kickbar",which is more in line with lockback type auto's,although kickbar's can be used with linerlocks.A kickbar is a secondary spring,or heat treated piece of steel that rests along the blade tang,when the trigger is released it pushes the blade open by springing into the area the blade just was,(between the liner),Then there are the "OTF" autos that companys like microtech,whitewolf,etc. make,thats another way,those are very difficult for the custom maker to produce,although they've been known to have been done by a few.I'm working on an auto framelock,seems to be where the pushbuttons need some representation.;)

Here's my less-than-professional sketch of what makes a leaf-spring automatic open.

http://www.internetbusinesslinks.net/LeafAuto.jpg

Hope that helps you visualize. If you need help on the release mechanism used for these kind of knives (the kind the switchblade combs were modeled after) let me know, and I'll do another bad sketch.:D

hey, thats great man!

yeah, id love another professional ;) sketch about the locking mechs.

anyone here know/can draw a picture of the dual action (manual AND automatic) knives mechs?

thanks

You asked for it!

http://www.internetbusinesslinks.net/AutoRelease.jpg

Remember, I'm not a graphic artist, but I play one on the 'net!:D

hey, your pictures get the point across, thats the important part.

thanks a lot, some things so simple just dont occur to me :)

The "leafspring" refers to the opening mech. spring I see.Ok I get what your saying,yea I guess thats another term,I was not familiar with that one,The drawings are good,simple,informative. well done. That backspring is basically the same thing as used in a standard lockback,just longer,I have 2 questions,what keeps the blade edge from contacting the backspring when closed,and why not just use a plunge button,instead of the trigger/leaf/pin assembly?(unless your going for the italian look)then forget the 2nd.

The first picture is the inside view if you were looking directly down through the handle slab. The second picture is how the trigger mechanism looks if you look into the slot that the blade folds into (side view). Basically, there are two leaf springs -- one to give the trigger some springback and one (bigger one) to make the blade go "Schlik!". The leaf spring that gives the trigger button it's springback can be replaced with a coil-type compression spring, like what you'd get out of an ink pen.

What keeps the blade edge from contacting the backspring is the same thing that keeps the blade of a lockback or slipjoint from doing it -- careful design and layout. If you look closely, the leaf spring (I always called it the ejection spring) has a curve toward the end that contacts the blade. This end of the spring contacts the blade just behind the plunge cut. It contacts the full thickness of the blade. (Is that clear as mud?;) ) The rest of the spring never touches the blade.

I have seen designs for more elaborate trigger mechanisms, but this one works, and it's relatively simple and much easier to construct than others I've seen. I've never seen a diagram of a bolster release or scale release, so I don't really know how they work. I'd like to, though.

It's a real kick to repair antique switchblades, especially when you're 15 years old! I fixed about 5 of the things, everything from replacing the backspring to replacing the ejection spring to repairing a busted handle scale. I haven't worked on one in over ten years, though.

so the kickspring/ejector rests on the kick?,so basically it's the same concept as the old kickers,just with thinner parts,maybe more refined,hmmm nice concept.

I've not been around here in a while, but I can chime in on how a Scale Release auto works.

The Scale Release auto design is pretty simple. The design is based on a lock-back pattern. In the same way that the locking bar of a lock back locks the blade in the open position, the locking bar locks the blade of the scale release auto in both the open and the closed position. In other words, there is a lock notch on both the top and bottom of the blade which the lockbar drops into.

In most scale release autos, the action of the blade is driven by a coil spring which is positioned between the tang of the blade and the right bolster. A space is cut out and shared between the blade and the right bolster to house the spring.

In order to "unlock" the blade with one hand, the blade and both sides of the knife all pivot on the pivot pin. The sides are attached in such a way that when shifted, the front end of the lock bar raises out of the lock notch allowing the spring to go into action and release the blade. The lockbar then returns to its resting position and locks the blade opened.

When it comes to making autos, the most collectible autos are the ones that have leaf springs and rocker bars. The lease collectible are the coil spring push buttons. The scale release autos fall some where in the middle. Most scale release autos are made using coil springs, although I have heard from one person who has had success using a leaf spring.

Hope this helps. -chris

Thanks, Chris. I'm starting to get a fuzzy mental image of what's going on there. I imagine that if I ever held and operated one, I'd understand a lot better. Nothing teaches like experience.

Well, it ain't exactly holding one yourself, but here is a link to a short video of the first prototype that I made. It's about 900kb.

http://www.chriscrawford.com/knives/Videos/Auto.mpg

Wow. That's a great video. Thanks for posting that link. I think I can see what you're doing. You're pushing on the bottom of the back scale, toward the front of the knife, right? Great video. I'm glad you posted it while I'm still at work. T1 lines are nice.:D

Yea, that's pretty much it. I hold the front of the knife between my thumb and first finger, The left side of the knife is against ball of my hand (under my thumb.) Using my middle finger, I press down on the back end of the right scale. This pivots the scale causing the front end of the lockbar to lift.

By the way, if you hold a knife in your hand as if you were pointing it at something with the edge of the blade down, the side to the left is considered the "left side".

-chris

That video prompted me to do a quick Google search for "scale release auto". I found another video with narrated instructions on how to open a scale release.

Go here:
http://videoknife.com/auto-dalton-scalerelease.html

Pretty good video. They also have a page with a video on opening a bolster release auto.

Cool!:D :cool:

I have the DVD from Chris. It rocks!!! Definite must see! The video quality is awesome. Plus it being in a DVD format, when all my buddies come over I play the beginning that shows some of his knives, then skip to the chapter where he gives his shop tour to show them what equipment he uses and then skip to the chapter that he shows the knife and how it operates. They love it. Of course they are only interested in the knives and not how they are made. But for those that would like to make one Chris really does a great job showing you step by step how to make one. And not just how he wants you to make it. He explains it in a way that you can make one using your own design or any size you want! Very nice video and well worth the money! :)
Ric

I just finished one with a slight twist. I built it one a lockback frame. Since I wanted to actuate the opening with my thumb, I made it a bolster release. The left bolster pivots at the lock bar pivot and has a pin that extends into the lock bar at the front. This lifts the front of the lock bar rather than pulls down on the back as a scale release does. Something a little different.

Gary