Originally Posted by sprucemoose
I just bought some of these from Spruce a few months ago. They are indeed listed under the Nicopress sleeves page along with the plain ones.
The plated ones have part numbers beginning with 2 rather than 1, with all other digits being the same. Per AC43.13 they are indeed required for use on stainless cable. Guess who found the out after completely rigging the aircraft using cables made with the copper sleeves? Live and learn.
Happens all the time Jeff. I hope what follows doesn't ruin your day. The correct sleeves for stainless cable are tin plated and start with "4".
There are two kinds of sleeve plating, zinc (part numbers start with 28) and tin (part numbers start with 428), in addition to bare copper (starts with 18). It's darn near impossible to tell zinc-plated sleeves from tin-plated sleeves after they've been floating around in a parts pin for a while. So what to do?
Bare copper is legal on carbon steel cable, and tin-plated sleeves are correct for stainless cable....so don't ever order zinc-plated sleeves. Just keep them out of your inventory.
Now remembering which sleeve goes with what cable is simplified. All you need remember is that you want a layer of sacrificial plating between the cable and the copper, just like we want cadmium on bolts.
With carbon steel cable, the plating is already on the cable (zinc or tin, either is fine by spec), so you can use a bare copper sleeve.
With stainless cable, the plating must be on the sleeve, as the cable has none.
I don't think there is any FAA document so misunderstood as AC43. Read page 3.
Information in AC43 is to be used only in the absence
of manufacturer's information. Put another way, if you do something using data in AC 43, and the manufacturer of whatever you were working with has published information available, you are wrong
This is what I wrote for Kitplanes...
Information specific to
Nicopress-brand oval sleeves is found in
Chapter 7 and Table 7-6 (Fig. 1). Like
much of AC43.13, the entire Nicopress
section is old—so old it may have come
directly from a CAM document when
AC43 was first created. Although often
cited by mechanics as their reference
source, much of the information is outdated
For example, the “Tested Strength”
values listed in Table 7-6 are too high
for design and do not reflect the notable
strength difference between carbon steel
cable and stainless steel cable. (Oddly
enough, the correct values, 2000 and
1760 pounds respectively, are found in
Table 7-3 in the same chapter.)
Note the asterisk next to the word
“plated.” It means (per the note at the
bottom of the table) that a plated sleeve is
to be used on corrosion-resistant (stainless)
cable. However, the listed 28-series
Nicopress part numbers are zinc-plated
sleeves. Zinc-plated sleeves on stainless
cable has been an obsolete recommendation
for more than 40 years.
Assuming you are using Nicopress-brand sleeves and tools (marked or not), you want "Nicopress Data Sheet - Oval Products" for product selection, and "Nicopress Instruction 32" for tool use and number of crimps.