Wire terminations

[az_gila]

Originally Posted by rv7charlie

Reading back through the last few posts, I'm not sure how carefully some of us are reading Bob's analysis, nor whether some of us understand their own crimper's action...

I carefully read the bit about el-cheapo jaw symmetry (one of his big points) and I know that my cheapo one is not symmetrical.

It's similar to this one -

http://www.cleavelandtool.com/Rachet...0#.WmJ_ZrpFyyI

or this similar one from Stein - a few $$ more but has the option of additional jaws for co-ax -

https://www.steinair.com/product/rat...er-frame-only/

And a good crimp will give me a nice formed crimp of the PIDG terminal metal ring portion that surrounds the wire insulation.

More

Just read the red edit above, and remember that my cheapo crimper is slightly different in closed jaw height, but the jaw with the least height is also a bit narrower. Reversing the terminal would certainly give poor looking results.

[rv7charlie]

Originally Posted by NTex

And you do *realize* that if I used PIDG splices for the CANBUS or RS232 splices on the backshell the bundles would be enormous, right?

Just trying to follow what TFM says.

No, I didn't. When did you specify that as what you're doing? Who/what is TFM?

[NTex]

Originally Posted by rv7charlie

No, I didn't. When did you specify that as what you're doing? Who/what is TFM?

Originally Posted by NTex

Bill,

Do you know what model crimp tool will work with those connectors you linked to? Seems the "real" ones are very expensive. Is there a cheap or generic alternative?

Originally Posted by William

I use these butt splices from aircraft spruce and though they are a bit pricey they work great. Just got to get the proper crimper and they install quickly and are a sealed connection. https://www.aircraftspruce.com/catal...esAWG20-16.php

Bill

Charlie - my interest in this thread was mainly for the environmental splices for purchase at aircraft spruce that Bill linked to. As you pointed out, that's an expensive way to make a simple butt splice connection.

However, those environmental splices are the only endorsed method for the CANBUS and RS232 connections. Here's what the Garmin installation manual says:

24.4.8 Splicing Signal Wires
NOTE
Figure 24-13 illustrates that a splice must be made within a 3 inch window from outside
the edge of clamp to the end of the 3 inch max mark.
WARNING
Keep the splice out of the backshell for pin extraction, and outside of the strain relief to
avoid preloading.
Figure 24-13 shows a two wire splice, but a maximum of three wires can be spliced. If a third wire is
spliced, it is located out front of splice along with signal wire going to pin.
Splice part numbers:
?Raychem D-436-36/37/38
?MIL Spec MIL-S-81824/1

Trust me, if I could use the PIDG connectors I would gladly do so.
In the case of the GTN 625 and G3X installs, Garmin requires the use of these Mil Spec 81824/1 environmental splices - at least according to the manual. I'm just looking for the right (read: cheap) tool to make those connections. As you pointed out, I'm not sure where else in an RV these types of connections would be required.


TFM stands for the.. manual.

Enjoy your weekend

[rv7charlie]

OK; now that I see the constraints...

The next question is, how open are you to 'alternate method of compliance' (to twist an FAA phrase)? If you're willing to do what will effectively accomplish the same thing without using the specified devices, I'd suggest looking at these:

https://www.google.com/search?q=sold...hrome&ie=UTF-8

If you can get past the old 'stress riser'/rigid connection argument (realizing that the shrink provides the support/strain relief on either side of the joint, just like a crimped connector), those little gadgets will get you to the same place, with only a book of matches as your crimper. And you can get them from the same source, Spruce (in addition to any decent electronics supply house).

Charlie

[pczar3]

Originally Posted by rv7charlie

Sigh...

We were taught to not go lean of peak on Lycs, too.

Look at that pic of the crimped connector before the shrink wrap is applied. Think there's no stress riser there?

Attachment method matters not. What does matter is supporting the wire beyond the stress riser point.

Sorry, but this solder/crimp thing just seems to be a bigger thing than primer wars, sometimes.

Charlie
No Holiday Inns recently, but a couple of past lives as an electronics tech.

Charlie, I have been in the business too. I was referring to what the USAF would accept when I was keeping F4 Phantoms in the air. I agree there are places for soldering as well. On the F4 the connector for the pitch actuator was a crimp only mandate. The wire traveled with the actuator movement. You would find yourself scrubbing hangar floors with a toothbrush if your boss found a solder joint on a repair you did on that connector. Same with the autopilot amplifier. Here's todays rule book from NASA. It shows both crimp and solder but is controlled by the application. NASA-STD-8739.4A ? 2016-06-30

Former tech, avionics specialist and still an engineer 50 years later.

[rv7charlie]

You've got far more experience than me, and better credentials, too. :-)

I agree with you; different conditions call for different techniques. If we don't understand what drove the original requirements, it's obviously safer to stick with established procedure.

But...

Many times, especially with highly structured projects, choices are made that might not be driven purely by safety, but by...well, for lack of a better term, convenience. As has been pointed out, it's a lot easier to ensure consistent results in a production environment if the tooling does it, instead of the random craftsman. For instance, some milspec/aerospace wire is surfaced with nickel, some with silver, some with tin, etc. The info I've seen (you'd probably have direct experience) says nickel surfaced wire can't be properly soldered, but it's great for crimps. Obviously, a tech who, for instance, tried to repair nickel plated wire with solder would be making a grave error. So in critical situations, the 'book' tells the tech exactly how to do every job, and he just does it, without question or variation. He doesn't even need to know why.

Now, the question is, does that apply to us? If we buy surplus milspec wire off ebay, as some of us {me} do, it might. Certainly, if we {I} don't do our homework.

On the other hand, if we know we're using the more common tin plated milpsec wire, I believe I have a bit more flexibility in the processes I choose, while still remaining safe.

Are we close to being on the same page?

Charlie

[DanH]

Originally Posted by rv6ejguy

Nothing beats the long term reliability if a properly sized, uninsulated terminal, properly crimped with a long length of double wall, glue infused shrink tubing on it- period.

I'm with you. Of course, as heretics in a world dominated by the Church of PIDG, we'll both probably get boiled in oil

[az_gila]

Originally Posted by rv7charlie

OK; now that I see the constraints...

The next question is, how open are you to 'alternate method of compliance' (to twist an FAA phrase)? If you're willing to do what will effectively accomplish the same thing without using the specified devices, I'd suggest looking at these:

https://www.google.com/search?q=sold...hrome&ie=UTF-8

If you can get past the old 'stress riser'/rigid connection argument (realizing that the shrink provides the support/strain relief on either side of the joint, just like a crimped connector), those little gadgets will get you to the same place, with only a book of matches as your crimper. And you can get them from the same source, Spruce (in addition to any decent electronics supply house).

Charlie

These are similar to the heat shrink/solder sleeves specified by Garmin for making connections to the outer ground sleeve of multi-conductor interconnect cables.

[Walt]

Originally Posted by az_gila

These are similar to the heat shrink/solder sleeves specified by Garmin for making connections to the outer ground sleeve of multi-conductor interconnect cables.

But be careful not to confuse typical shield terminating solder sleeves with "butt splice" type splder sleeves, they are not the same thing. Butt splice solder sleeves are great but the cost is quite high. For the CAN bus and 232 wires that have to be spliced, my method is to solder and cover with double wall adhesive shrink tube.

[rv7charlie]

Walt, that's what I do, as well, but I have the soldering skills. I've got quite a few soldered/heatshrunk joints in my project. A lot of builders don't have the skillset & tools to do soldering, and don't have the interest in learning.

Most of the solder sleeve prices I'm seeing are around $.80 each; about half the price of the crimps shown in earlier posts.

EDIT: or maybe, less

https://www.amazon.com/dp/B01ILSEDWI...a-362741562167

Charlie