Aircraft wiring, terminal ends, crimpers and how to use them

Bartman

Bartman

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Asking about sizing wires brought up a ratcheting crimping tool (by Hiperbiper maybe?). "Crimping" is the process by which a bare wire is locked into place within a terminal fitting by a mechanical crushing process.

These are the terminal ends, they are color coded by wire size
www.aircraftspruce.com

Ring Tongue Nylon Insulated Pidg Terminals | Aircraft Spruce ®

Ring Tongue Nylon Insulated Pidg Terminals Each insulated PIDG terminal consists of a tin plated copper body, a tin plated copper wire support sleeve and a color-coded insulation sleeve.
www.aircraftspruce.com www.aircraftspruce.com

This is the crimping tool that was mentioned, ATS E300-002

TERMINAL CRIMPER (R/Y/B) from Aircraft Tool Supply

TERMINAL CRIMPER (R/Y/B) - Powerful full-ratcheting crimper with safety release and adjustable crimp pressure. Very comfortable rubber handles and ergonomic design makes it easy to install multiple terminals. Crimps Insulated Terminals & Splices: 22-10 AWG red, blue, and yellow.
www.aircraft-tool.com www.aircraft-tool.com
Screen Shot 2022-01-04 at 08.07.22.png

And this is an excellent how-to video demonstrating how to do a good crimp.
 
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Ratcheting crimpers are definitely the way to go.

I bought several when I was rewiring my boat. Proper crimping in that application is important because every connection must be watertight. Wires exposed to salt water and current corrode rapidly, especially when in contact with different metals. Weight is not a factor, so the best approach is to use oversized gauges and adhesive heat shrink crimps. But if you don't have the correct size and shape dies, the crimper punctures the heat shrink and you get leaks.

If I was doing it from scratch, I would buy one of the sets on Amazon that comes with multiple interchangeable die sets, for insulated, uninsulated, heat shrink, ferrules, etc.

 
Does that crimper do the small connections for avionics plugs?

The jaws of the crimper I linked to above can be changed, new sets are about $20 each.
 
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While I do have different jaws for different types of connectors the ones I use most are the ones Bartman pictured.
20220106_142546.jpg
Left to right: really sharp small wire cutters. These things will cut a piece of thread. Makes clean end cuts and helps assembling coax cable. Orange crimpers for insulated terminals. Blue wire strippers. Strips Tefzel wire without damaging the wire. Green crimpers for coax cables...crimps the center pin as well as the sheath band.
20220106_142758.jpg
Big ratcheting crimper for 0, 2, 4, 6 and 8 gage cables. Cheap multimeter with big clip on ground lead. For when you've only got one hand to spare...
Different sizes heat shrink sleeving.
Last but not least a pocket-sized mechanic's bible (AC43.13b) which includes a handy wire sizing chart.
I have a roll-around bag with lots more crap but just this stuff would let you fix almost anything in one of our birds.

Chris
 
The crimping tool in the first post has jaws that can be swapped out, I just bought the coax jaws for about $18. Here's a guide for stripping RG400 coax cable before crimping an end on.
 

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Bartman said:
Where'd you get that? :unsure:
Click to expand...
Found it at Aircraft Spruce after all...
www.aircraftspruce.com

ASA Aviation Mechanic Handbook | Aircraft Spruce ®

ASA Aviation Mechanic Handbook A core reference manual for mechanics, aircraft owners, and pilots, this book compiles specs from stacks of reference books and government publications into a handy, toolbox-size guide
www.aircraftspruce.com www.aircraftspruce.com
Really a great reference book.
Chris
 
Question about terminals for #8 and #2 wire. I have noticed some variation in terminals available. Some are crimped. Others are more heavy duty for soldering. Still others are bare copper. Also, some have an insulating sleeve while others are bare. Are there any guidelines on what to use where?
 
I've always used aircraft grade terminals made by AMP. Automotive terminals have poor fatigue resistance, the AMP terminals are a dense copper that hold the crimp well. Use a rubber nipple over the connection for insulation.
I mostly got mine from Aircraft Spruce as I needed them...

Chris
 
Hiperbiper said:
I've always used aircraft grade terminals made by AMP. Automotive terminals have poor fatigue resistance, the AMP terminals are a dense copper that hold the crimp well. Use a rubber nipple over the connection for insulation.
I mostly got mine from Aircraft Spruce as I needed them...

Chris
Click to expand...

Is there a specification or standard for aircraft grade terminals?
 
Did a little google searching and found MIL-T-7928. Spec covers insulated and uninsulated copper terminals. Easy enough to Google a manufacturer and see which of their terminals meet that spec.
 
Found this ref in AC 43.13-1B. Para 11-174.d.

Copper Terminal Lugs. Solderless crimp style, copper wire, terminal lugs should be used and conform to MIL-T-7928.
Click to expand...
 
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Hot tip: my IA says you can buy Mil spec Tefzel wire in NAPA for half the cost. Apparently it is commonly used by long-haul truckers in rather large quantities.

Wish I knew that before I spent 12 bucks a foot at Aircraft Spruce for 2 GA starter cable. 18 feet from battery to starter. Not cheap.
 
Any suggestions on best method to butt splice heavier gauge wire?

#353 is the wire that runs from the master solenoid to the ammeter. The 8ga wire that ACA sent me in the electrical update kit is 6 inches short. Normally I would cut a new piece for the run, but at 15 feet that is 100 bucks of wire!

I have an anvil crimper for heavy lugs, so if an amp crimp and heat shrink tube will suffice, I'll do that.
 
i'm pretty sure I had to buy a heavier gauge crimper for the larger wires. it isn't a battery terminal crimper but just made for larger insulated terminal ends.
i can grab a pic when i go to the hangar later
 
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