[Paul Eastham]

I've read AC43.13 about how cotter pins are supposed to look when installed, but I am wondering: what's the right tool for the job? I usually end up manhandling them with the snout of my diagonal cutters, which is prone to slipping and generally making a mess.

Do you bend first then trim to proper length? What tool do you use to trim when they are up snug against the nut/bolt as required?

If you trim first, it seems like you need to apply a lot of force very near to the bend location (i.e. not much mechanical advantage due to having a shorter "lever"). How do you grip them?

Surely there must be an easy way!

 

[rv8ch]

cotter pin

I usually install them with needle nose pliers, start the bend, use cutters to trim the excess length, then just push the bend tight against the bolt/nut as appropriate.

 

[Jekyll]

Tools that make an easy job of cotter pin installation: needle nose, diagonal cutter (dykes) and standard screw driver.

Top leg gets bent with needle nose and snipped with dykes. I then snip the lower leg to the approximate length (a measured eye comes with experience, years as a mechanic on older military helicopters gives plenty of experience with cotter pins and safety wire) and set by pushing down with the snout of the needle nose or a standard screw driver.

I don't recommend trying to manhandle pins with dykes as they will cut into the metal.

Jekyll

 

[robertahegy]

A Duckbill pliers works well for bending cotter keys.

Roberta

 

[jarhead]

Most of the time I prefer using safetywire pliers for cotterpins. I have a couple pairs - the set I use for cotterpins and other non-safetywire tasks are cheapies, and don't get used to do safetywire.


Having said that, the proper pliers for the job (as noted by previous posters) are needlenose or duckbill pliers, and diagonal cutters for trimming the legs to length.