Rivets

[Fisher]

Hi Bill, Originally had this question in another forum, but was advised to move it to this one, It was also suggested that 2.8mm is too big for rivet size. What would you advise for future projects?

ORIGINAL POSTED TOPIC:

Hi, Sorry new to the forum and knife making. My first project is a spring-assisted knife. Cannot decide which type of rivets to use or what size. The closed knife will be 135mm or 5 inches long. The guide holes already drilled are 2.8mm diameter but can be opened up.

What would you recommend? Brass, copper, or aluminium, and the diameter of the rivet shank?

Thanks
Rob

[Bill DeShivs]

I don't think they are too big, but there is no reason to use stock that large unless it's a very big knife.
Just look at other knives of the type you are building. Anything from 1MM to 2.2MM is common.
Brass or nickel silver is the preferred material for ease of use.

[Fisher]

Thanks Bill.

[button_man]

.
There is a saying: "A little knowledge is a dangerous thing" -- which is entirely appropriate for this post!

When two different metals are in contact, there may be a chance for electron transfer. This is why 1-cent coins made of zinc & plated with copper (beginning partway into 1981, and thereafter) often are corroded.

This 'galvanic corrosion' is more likely in some combinations than others; it all depends on the number
of electrons in the outer valence of each metal.
Therefore, your rivets should be made of a metal that has
a low potential to react with the liners to which they will be attached.

'Contact electrification' is a complex subject and you really should consult a metallurist for expert knowledge in the field. I am barely qualified to even write this post.

https://periodictableguide.com/periodic ... electrons/
.

[Bill DeShivs]

I have seen no evidence of galvanic corrosion on knives.
Brass and bronze are copper alloys-as is nickel silver.
Steel is also used for rivets, both carbon and stainless. Aluminum use in knives shows no galvanic action.
Galvanic corrosion usually requires a liquid medium, usually salt water.

[button_man]

.
I realize that a fluid conduit is usually involved; but I have seen literally hundreds of cents (we don't officially have "pennies" -- those are UK) that are horribly corroded.
It seems unlikely that all of them were marinated in brine long enough to instigate electron transfer.

There is apparently such a huge imbalance in the outer electron shells that transfer is achieved without any significant liquid presence.

The details of precisely how this occurs in some paired materials and not in others must be left to greater minds than mine.

I just thought I'd mention the topic as being of possible consideration to a mangler....
.