Floating spring

How a Swiss Army Knife works


The SAK is a sandwich construction and use a floating spring mechanism for the three functions.

On the pictures you can see a Victorinox spring with the matching functions in open and closed position. A Victorinox knife is designed and made by the factory to have all the functions opened at the same time. This mean it is in their philosophy to be in the elastic region.

As a general rule I only open a few functions at the same time or make sure they are locked out fully.

This is just a rule I have to be gentler on knives and especially used knives that others have damaged. To open all the functions on a damaged knife may damage it further. So I made a habit of doing so on all knives.

On the picture you can see the floating spring and this mean that you will be able to see the center rivet go up and down when opening the functions. This means that you can have precision and functionality without hurting the finger nails or break the spring.

This design makes it possible to use 3 functions with the same quality of use on all. It requires precision and advanced production to make this knife. It needs to be riveted with very good precision to be able to have the clockwork mechanism on a Swiss army Knife.

The spring is advanced not only to flex in the opening and closing but also to hold the function when locked out or in.

The secret to a Swiss Army Knife is the spring!



When opening all the functions on a knife it is very normal on a Swiss Champ for example that it require some more strenght to open some of the functions. This is normal and ok!


From history we know the introduction and pioneer work by Victorinox on the stainless steel.

By 1931 this had the properties and abilities that Victorinox did want and the new hardening plant was set up.

The use of stainless steel is very important in a SAK because this makes it much better against corrosion and it is much easier to clean. Today all the functions are polished and got production perfection.

On a Swiss Army Knife it is important to know about the spring and the stampings and emblems used in history.

For a collector the emblems, stampings and how the functions and parts look are important.

For a knife to have functionality it need to be quality made or else a SAK would not work properly. A Swiss Army Knife is the most advanced knife tool I know about and the comfort with precision and quality goes hand in hand.

The most impressive for me is the spring and how the steel has gone through all the steps in the production to become a product. It needs to be able to work for a lifetime and this is advanced technology with very many factors to know.


The larger Victorinox automation process started from my information from 1945. this is an on going process today.

Here is a show board i made with the springs and functions + parts and liners. The liners are random set.

The bushings are made to be on the rivets and these hold everything together and they got an edge around the head that is pressed into the plastic handles or scales. It is almost impossible to pull a SAK apart.

The spring for the corkscrew and blades is also a floating spring because there are three functions on one spring. Just like the can opener, flat screwdriver and awl spring.

There are 4 rivets on a SAK and 3 bushings, number 4 is riveted without.

The liners on this are made of aluminum and the rivets are made of brass, the spacer is made of nickel-silver I believe.

A SAK is a sandwich construction with layers made of a spring and the functions, then a liner and another layer with a spring and functions.

It may not look advanced when you look on this board of parts but I am one 100% sure that it is very advanced if it is Victorinox or a Wenger Swiss Army Knife. The precision and materials is pretty incredible.


One extra interesting part for me is the spring for the blade and it is a slip-joint construction like we know. When pressure against a surface with the edge the backside tang part of the blade will press against the spring. Any wrong here and the spring would bend, slip or break, this i have never experienced with a SAK.

the spacer is also special becuse it does not only fill the space for the small blade it also stops against the spring end.

The Victorinox production with evolution and changes of a product is not only done to make a product better looking and with the best possible functionality it is done to reduce cost of the production as well. Victorinox got a constant improving of the production and products. Some is for evolution and functionality, some for cost efficiency.

The spring on a SAK is advanced and serves more tasks than I have mentioned it also does a job in a fully assembled SAK to make it stabile. At least this is my understanding that the shape of the spring at different areas will function to prevent twisting or unwanted movements.

How much the spacer has to say besides filling the gap and make sure about the functionality i do not know. It is interesting.


it is interesting with the spring, it need to have a pressure that is enough for functionalty. It need to be comfortable and with the correct pressure so one do not hurt the finger nails. A SAK love some oil on the friction parts.
This is how it sit on an assembled knife, also see the show board. I put this Picture together and it shows for me the technology as i see it. The spring is advanched!
With a slip joint mechanism and if one use much force against a surface with the edge then one will at the point x get a force that goes backwards. Atleast this is my self learned knowledge. It is important that the precision is there. I have never had a SAK fail here. I was wondering since it is a floating spring that it somehow could move the entire spring backwards.
A SAK is a great invention!
the ratio around the rivet or pin is special. I love this technology.


Until today i have never experienced a spring on a SAK fail.





Safety factors

Today there are many folding knives and different Brands in the world. I like them very much. There are tons of quality products to choose from. That is a good thing in deed. Most SAKs have a riveted design and this is a part that once more needs underlining. A sturdy riveted design/construction will not fail. A pivot screw got advantages when it comes to cleaning and adjusting the mechanisms. I like them! I have noticed on videos over the years that hard use may loosen the pivot making the functionality difficult. There are much talk about Loctite and avoiding this problem. This is a preparation issue for users and if you prepare it will or may not happen. Remember that it may be smart to bring something to adjust with just in case. It is not just folding knives that have such problems. You can see this on fixed blades and the knife handles that are fastened with screws or other turning attachments. They may get loose from hard use.


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Antall tegn tilbake: 160
OK Sender...

Sawatito Samonakato | Svar 10.07.2019 12.35

My kommentar this sak is a good sak

Trond 10.07.2019 14.01

Thank you very much, i agree Best Regards

Doug Wheeler | Svar 25.06.2017 17.20

Does anyone have any recommendations for breaking in hard to open tools on a new SAK? One example, the inline Phillips drivers on my S557 is nearly impossible.

Trond 27.06.2017 09.00

you are welcome , i have done this before, when open i move the inline ph. fully open to half open many times. It will become easier in time. BR

Doug 26.06.2017 23.43

Thank you Trond. I will give it a try.

Trond 26.06.2017 08.44

Hi use a plastic Device with a tip under for opening. There are sometimes differences when they are peened that can cause hard opening functions.Lube first

jim r fisher | Svar 16.08.2016 17.20


Trond 16.08.2016 22.22

to much force during use may have damaged the rivet or spring, it is out of the dynamic and elastic region. It is most likely damaged, sorry. BR

Trond 16.08.2016 22.20

Hi! It may be two reasons. 1: It can be that the rivets are peened to hard with additional damage to the liners. 2: it has taken to much force during use cont..

Antonio | Svar 14.05.2014 16.28

Thanks for the time you spend wrinting this great report.

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Nyeste kommentarer

26.07 | 23:05

Hi and thank you very much for question. The closest I know is the Master Fisherman 1.4753.72. The. 73 is related to what inlay it got maybe. Best Regards Trond

26.07 | 19:22

Hello Trond,
I received a Mechanic in a red/white Victorinox box. The box is stamped item number 1.47 53.73. Do you know what knife goes in this box? Not Mech

01.07 | 23:13

Hi, sure I would like to see, BR. Trondsak@sakhome.com

01.07 | 16:24

Hello Trond.

Would you be interested in seeing progress pictures
Of my custom Champ with Voyager digital clock scales.
I could email them to you.


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