[TR] more torqueeness, security, etc.

[Karl Vacek]

There are lots of ways to safety-wire fasteners.  Bolts can have safety-wire 
through the head or the shank (near the end of the threads).  If you wire 
through the threads of the bolt, you should use a castellated nut, torqued 
properly and then turned as appropriate (ie don't torque so hard you break 
the fastener) to align a set of slots in the castellated nut with the hole.

Safetying is similar to cotter pinning, but you can safety things that can't 
be held by a cotter pin.  A cotter pin can hold a nut from turning.  Safety 
wire can do that, or keep a screw, plug, etc. etc. that is threaded into 
something, from turning.

Safety wire is threaded through the hole, then bent together so there are 
two lengths of wire running parallel,  The wire is then twisted (in the 
appropriate direction) to keep the loop on the head or shank of the screw, 
and fastened to the next screw or to a hard point.  Easier to understand if 
you've seen it.

When you safety something, remember to install and tension the wire in a 
direction that will tighten the fastener - not loosen it.  Easy to mess that 
one up.

Safetying is normally done with stainless steel wire, .032 being a common 
size for smaller fasteners, say 8-32 up to maybe 5/16".  Above that you 
might want to go .041, maybe larger, depending on the size of what you're 
safetying.  My perspective is sirplanes, and we use lots of .032.

Aircraft mechanics safety things all day long.  If you look for a copy of 
FAA Advisory Circular AC 43.13 you will see lots of examples of various ways 
to properly safety wire bolts, screws, plugs, etc.

Karl




> >Does wiring a nut on mean 'tightening it,
>> then drilling a hole thru nut and bolt, then sticking wire thru it?
>
> No.  The hole is already drilled through the nut.  The hole does not go 
> through the threads.  There is no hole in the bolt.  After the nut is 
> installed, the safety wire is put through the hole and looped tightly to 
> an adjacent object, perhaps another nut.
>
> I used to wire the wheel nuts on my MG Midget because the light torque 
> specified for those little 3/8" studs was not enough for the flat washers 
> of the wheels I was using.  After having stock steel wheels (torqued to 
> specs!) loosen up, I was not going to take a chance with the flat-washer 
> setup on those alloy wheels.
>
> Of course the same can  be done with bolts.  The hole is through the bolt 
> head.