Crimp or Swage line leadout

[Dave Nyce]

When assembling the thimble into the ends of the leadouts, a copper sleeve is crimped or swaged to grip the line.  I have a wire terminal crimping tool, which compresses the sleeve from two sides.  But I'm not sure what the difference is between crimping and swaging.  I suppose that swaging may squeeze at more than two points and maybe provides a stronger joint, but would like to know exactly what is the difference between crimping and swaging.

[GEOFFREY]

About 60 dollors

[Ralph Wenzel (d)]

There is a huge difference between "crimping" and "swaging". As you note, the crimping tool concentrates all the force at one of two points along the sleeve. This generates enormous stress in the leadout cables, and can lead to early, sudden failure.

A swaging tool, on the other hand, spreads the load along the length of the sleeve, and the process generates such force that it actually causes the brass or coPper of the swaging sleeve to "flow" into the weave of the leadouts, which lock them into place withoug generating a single stress point. Note that the swaging tool uses compound linkage to generate this force, rather than a simple "pliers-type" action.

There is one other thing which I do to avoid problems with swaged connections. I "relieve" the free end (the end away from the thimble) with a tapered reamer so that the sleeve flares out, and this helps prevent the leadouts (or lines) from suffering a bending force at that point.

The industry standard for these swaging tools goes under the trade mane "NicoPress", and was originally developed for the telephone industry. The tool I purchase was made by Carl Stahl, and has 4 swaging grooves for different sizes of sleeves. You can see it at www.savacable.com -  It cost around $110 including shipping. There is a map on the website showing where to purchase their equipment in each area.

Ralph

[Bob Zambelli]

My next safety article in C/L World deals with this exact issue.

While crimping and swaging are similar in principle, I favor thew latter for reasons discussed in the article.

Wire wrapping is also a fine way of dressing the ends.

Keep in mind that real aircraft use swaging on critical flight control cables.

Here's a picture for you.

Bob Z.

[Andrew Hathaway]

Crimped ends can work fine and last a long time.  For the longest time all the leadouts and line ends that dad and I used were finished with copper sleeves and crimped with a Craftsman solderless terminal plier.  Some of those old planes are still flying with crimped leadouts after nearly 20 years.  I've yet to have a crimped connection fail.  It's more important to inspect the lines and handle for wear or damage on a regular basis then how the line ends are finished.  Line ends wrapped with copper wire can fail too, inspecting the lines regularly can identify potential failures before they happen.

[john e. holliday]

There is only one place/event I would ever use a crimped line in.  It is combat as the lines usually don't last that long.  I use Carl Shoupe's swagging pliers and make the furrels out of copper tube(mine are 3/8 of and inch long).  You have to remember to keep going around the joint until you feel you can't do any more.  Have pull tested a single .015 line to 80 pounds with no failures or slippage.  I can do a set of lines in about a fourth of the time it took to wrap them.  DOC Holliday

[Bob Zambelli]

Ralph - well stated.

Here are my cable service tools - both from SAVA. ($$$$$$$$$$$$$$$ but worth it)

I also taper both ends of the ferrule to allow a flex path.

I use ONLY copper tubing and I anneal it first.

Bob Z.

[Dave Nyce]

Thanks a lot for all of that info!

Dave

[Bob Disharoon]

Ralph - well stated.

Here are my cable service tools - both from SAVA. ($$$$$$$$$$$$$$$ but worth it)

I also taper both ends of the ferrule to allow a flex path.

I use ONLY copper tubing and I anneal it first.

Bob Z.

Bob..I have the red handle cable cutter you show, and that baby means business...I have cut 3/16.. 7/19 stainless wire rope with it and it cuts clean..well worth the $$$...Bob

[Larry Cunningham]

Crimped electrical connection are de rigeuer in most electrical applications nowadays,
including hel-rel stuff. They make a particularly good electrical connection with a lot of surface
area involved, and reasonable strength. No solder please, the proper crimper makes a GAS
TIGHT connection!

Of course, serious cable end treatments, with the proper crimp and tool used, are among the
strongest you can produce.

Unfortunately, it appears that in every case, at least a ~$150 pro crimper tool is needed.

The very worst example (don't ask me how I know) of flight line terminations is to take a section
of 1/8" OD brass tubing, and cut it into segments. Notice I said brass, which is what I used at first.
I was using a large needle nosed plier to crimp the joint, and I immediately could see that it was cutting
the flight line.. My (stupid) response was to take my #11 Exacto blade and SKIVE (word I learned
from Bob Hunt) the inside edges of the brass "crimp". That worked, but only marginally better.

I also tried the very short chromed (aluminum) tubes that I thought were intended for the purpose.
No, I don't think so, although the ends ARE finished a bit..

Finally I figured out that soft copper tubing was a better choice, however my large needle nose "crimping
pliers" did not cost ~$150, and never did a great job.

Fine copper wire is best; saturate with thick CA to keep it from unravelling..

My purpose in life is to serve as a Bad Example.

L.

"What the country needs is dirtier fingernails and cleaner minds." -Will Rogers

[Dave Nyce]

I looked on the Carl Stahl website for those tools.  The tool shown in the photo on Bob Zambelli's email is the model number T-185.  So, I'm going to check into getting one.  But I'm still not sure about what the difference in definition is between a crimp and a swage, because the Stahl website calls the T-185 a compound crimping tool, and mentions crimping copper and aluminum sleeves.  But then it also mentions swaging over nylon.  Maybe swaging is a type of crimping?

[don Burke]

Swaging an aircraft cable is done in a machine that holds the cable and end fitting then subjects the fitting to compression with a rotary "hammer" affair.  I've seen them used, that's the best way I can describe it.  Got to remember that aircraft swaged cables are always pre-loaded in tension, and never see the bending we can get in leadout and line connections, usually from unreeling, reeling and hooking up the wires.  In use our wires are in tension.

I think that both swaging and crimping introduce a stess point to the wire, (particularly solid lines), and are not the best way of doing it.  Double wrapping with copper wire with a dot of epoxy as noted at the eyelet end is the most flexible way.  Soldering the wrap makes the same kind of stress concentration as swaging or crimping.

[john e. holliday]

Hey Don, I myself would not even think of swagging solid wire lines.  Nothing there to push the copper into.  On my TQR's I have swagged cable leadouts and flying lines.  DOC Holliday

[Geoff Goodworth]

Hi guys

The fishing stores have some pretty high load fishing leaders and the like that use aluminium ferrules.

Has anybody seen an issue with corrosion between stainless steel leadout cable and copper tube ferrules?

Cheers

Geoff

[Bill Little]

HI Avid,

Looking at Bob Z.'s post with the wire ends, "A" is swadged, "B" is crimped.

Sometimes the terms are incorrectly interchanged.  Swadgeing changes the actual diameter of the sleeve through compression whereas crimping simply flattens it. 
When I started my plumbing *career* I had tools to swadge the ends of soft copper pipe to solder another piece into it.  It expanded the end large enough to let a normal size into it (created a female end) without damaging the pipe.  Swadgeing our lines is the opposite effect.

[Dave Nyce]

Thanks Bill.  I'm trying to find out where to buy one of those swaging tools.  Looks like I have to locate a distributor and order it through them.

[Bob Zambelli]

Gents - the swaging tool (T-185) and the cutter (C-7) are both available from SAVA in NJ but I'm not sure if they deal directly with the public.
You can call or e-mail to find a distributor.
Since they are a bit pricey, why not buy a set for your club and spread the cost? After you see how beautifully they work, you will not regret the decision.

Here's something to consider - many believe that the rigid section of the dressing (crimp, swage or wrap) will flex relative to the leadout, causing a riser.
This is not the case - try it. Pull on your leadouts and move them fore and aft. You'll see that the flexing is at the wingtip, not the dressing. Like in the picture.

Anyhow, it's all in the next CL World.

Bob Z.

[Dick Fowler]

I looked on the Carl Stahl website for those tools.  The tool shown in the photo on Bob Zambelli's email is the model number T-185.  So, I'm going to check into getting one.  But I'm still not sure about what the difference in definition is between a crimp and a swage, because the Stahl website calls the T-185 a compound crimping tool, and mentions crimping copper and aluminum sleeves.  But then it also mentions swaging over nylon.  Maybe swaging is a type of crimping?

I was in the high pressure hydraulic hose business at one time and we used both crimped and swaged fittings on hose ends. There is a significant difference between crimping and swaging. Crimping moves the dies in toward the center normal (at right angles) to the inner element. Regardless of the number of compression die elements, it is still technically a crimp if it moves in from the sides. A swage uses a die and a pusher. The die is radiused at the end and the pusher forces the sleeve into the die causing a uniform compression of the sleeve around the entire circumference of the sleeve as it is forced into the die. Same process that forms the ends of rifle cartridges.

Our sleeves are so small that swaging presents some problems but would be possible.

Forgive my crude sketch.

[Bob Zambelli]

Dick - when I was in the aircraft controls business, we used something very similar but the die rotated and worked its way up the ferrule.

We were required to do destructive test after a certain number were made - the failure was always in the cable, never the swage.

So, the one you used actually slides into the die and then the die opens.

Bob Z.

[Rod Claus]

Hi Bob,
Before I go hunting around for one of these SAVA tools,just how much are they???
Thanks

[Bob Zambelli]

Hi, Rod - I don't have the exact price but they're probably in the $100.00 area - EACH.

I got mine in the mid 80s as a gift.

Here is the best way to check what's current:  <sales@savacable.com>

Bob Z.

[Bob Zambelli]

I just got a call from SAVA.

   Swaging tool, T-185 is $108.00
   Cutter, C07 is $74.00.

             Bob Z.

[Greg L Bahrman]

Just some more data for whatever it's worth. I spoke with Bob Z on this issue some time ago and purchased the swageing tool (SAVA) he recommends. I used it on my Nobler with the FP40. It was fast and neat and has passed all the necessary pull tests that contests require. I think it's great and will continue to use it.   

[Garf]

Try Ebay.

[phil c]

I modified a typical hardware store electrical crimping pliers to make a simple swage.  Used the Dremel carbide bit that is .060 od by about 3/8 in. long to grind matching half circles right up close to the hinge(the only space available).  I use it with some nickle-plated steel fishing line crimps from Mel Schuette, .09 od x .059 id.  I made up a bunch of test pieces using 015 and 018 line exactly like the rule book shows- slide on the crimp, fold the line over, slide it into the crimp, and then swage the middle of the crimp by squeezing it in the notches and turning it, about 5 times, until the middle of the crimp is squished in uniformly.  They all held up to a normal pull test and the line broke at typical values- about 35 lb. for the 015 and 50 lb. for the 018.

So I made a bunch of F2D line using the .016 brass-plated music wire stock.  They have held up fine.  One end slipped and pulled itself shut, but otherwise no problems.

If you are going to do crimps you really have to experiment with the line size, crimp size, and the crimping pliers to find the best combination.  The tool has to be able to squish the crimp down evenly round and into the wire.  You need a different size on the tool for each size crimp you use.  And the crimp has to be matched to the line size.  .012 line in the above crimp tubes will just slip.  There isn't enough meat for the tool to squish the crimp down far enough.

[Dave Nyce]

Thanks everyone for the info, the definition of swaging vs. crimping, the tool type and cost.  Couldn't ask for more.  Thanks!

Dave

[john e. holliday]

Carl Shoupe makes two sizes of swagging pliers.  He also makes a tool for making line clips for the hard point handles.  Of course with his pliers, you don't just squeeze once as that is not enough.  You have to keep going around the tube until it is completely round.  Done right there is a little bell/flare at each end of the tube.  DOC Holliday

[Dave Nyce]

I ordered the Stahl swaging tool and the cutter today. 

Bill: I've finished repairing my Nobler, except for the ends of the leadouts.  I'll swage them when I receive the tools.  I installed a 3" Tom Morris bellcrank.  It came with the connections to the bellcrank already done.  Now I need to make up the ends where the lines will connect.  Then maybe we can get together for me to receive further instruction.

The plane doesn't look all that nice now.  Since I didn't have any matching blue covering, I used silver covering on the repaired areas.  But that doesn't matter since this will be one of my trainer planes, and is expendable.

I also have ARFs of the Tutor II and Score, which aren't assembled yet.  They can serve as additional trainers, if you think those models would be suitable.


Dave

[Larry Renger]

I have always crimped, but use a round nose pliers to do the job.  I do three crimps per ferrule at 0, 90 and 0 degrees.  The ends of the ferrule are chamfered from the inside, then I put heatshrink tubing over the whole thing to help ease any possible stress at the ferrule exit (and color code the lines).  I have NEVER had a failure at the line end.

I do "cheat" in that I loop the line end over the outside of the ferrule and back through it rather than doubling it straight back as per AMA directions.  My way locks that end against slippage, where the AMA technique does not if the crimp/swage isn't perfect.  I don't know who designed the AMA loop, but they should rethink it!

[don Burke]

Larry,
I think the idea of doubling back through the sleeve is so that the line will in essence form a "knot" that will help keep the line from just slipping back through.  I think going around the outside doesn't give this kind of safety factor.   When the crimp isn't exactly up to snuff the looped around line can just slip on through.  Ask me how I know!

[Bill Little]

I ordered the Stahl swaging tool and the cutter today. 

Bill: I've finished repairing my Nobler, except for the ends of the leadouts.  I'll swage them when I receive the tools.  I installed a 3" Tom Morris bellcrank.  It came with the connections to the bellcrank already done.  Now I need to make up the ends where the lines will connect.  Then maybe we can get together for me to receive further instruction.

The plane doesn't look all that nice now.  Since I didn't have any matching blue covering, I used silver covering on the repaired areas.  But that doesn't matter since this will be one of my trainer planes, and is expendable.

I also have ARFs of the Tutor II and Score, which aren't assembled yet.  They can serve as additional trainers, if you think those models would be suitable.


Dave

Hi David,

Since you can fly fine, and do loops, etc., plus you have full size aircraft.helicopter experience, your "trianing" is going to consist of getting sizes and shapes down.  Any of those will be suitable is they are powered correctly.

[Keith Spriggs]

Here is my candidate for a cheapo swageing tool ( 75 cents) along with a completed swaged connection and a test with a 100 pound anvil. A bench vise is used to compress the tool.

[Bob Zambelli]

"Here is my candidate for a cheapo swageing tool ( 75 cents) along with a completed swaged connection and a test with a 100 pound anvil. A bench vise is used to compress the tool."

Now that's what I call CLEVER!! 

Keep up the good work.

Bob Z.

[Steve Fitton]

On my smaller (46 and below) planes, I moderately crimp copper sleeves over the sullivan gold braided leadouts, then flow solder into the sleeve.  Tom Dixon does his leadouts this way, even on his big stuff.  He claims not to have had any failures, and I must report no failures on my stuff, albeit none of it has more than a few hundred flights.

It would be interesting to test to failure the various types of terminations, but I can't think of a way to simulate the fatigue they would sustain from flight, vs just just testing ultimate load, or working the wire back and forth to try and excite a failure right at the exit point from the sleeve.

[Bill Little]

Every *crimped* connection that I have seen fail did so from fatigue at the point of the *crimp*.  I have never seen a wrapped lead out do so.  I have no experience at all with swadging any model lines.

WE can discuss this ad infinitum, and some will claim their way is the absolute best, regadless.  So, just pick a method you like and go from there.

[john e. holliday]

In all the years I have used wrapped lines for everything except combat.  At VSC one year I had put up a flight with my Brodak Nobler.  Lost count of how many flights on the set of lines.  I was getting ready to disconnect from the plane when I noticed three strands of cable were loose.  Needless to say I redone those lines before my next flight.  I now check my lines after every session no matter how new they are.  DOC Holliday

[Bill Little]

In all the years I have used wrapped lines for everything except combat.  At VSC one year I had put up a flight with my Brodak Nobler.  Lost count of how many flights on the set of lines.  I was getting ready to disconnect from the plane when I noticed three strands of cable were loose.  Needless to say I redone those lines before my next flight.  I now check my lines after every session no matter how new they are.  DOC Holliday

Hi Doc,

I would suspect that far too many of us are remiss in inspecting our lines!  I know I do not do it often enough.

[Dave Nyce]

I was very surprised to receive in the mail today, a letter from Ralph Wenzel which had two line leadout sections taped to it.  They each comprised about a six inch length of cable with a thimble attached at one end.  One termination was crimped (labeled: a "standard Sullivan crimp") and the other was swaged (labeled: "swaged w/ Stahl press"). 

The crimped one looked like a section of it was squeezed between the two jaws of a crimping tool.  Conversely, the swaged one was uniformly of a smaller diameter in the swaged area, which was about 80% of the length of the copper tubing.  About 10% of the tubing was left un-swaged at each end.

I was amazed at the extra effort that Ralph expended in order to help me to understand this.  Thanks a lot Ralph!!!!!!!!!!

I just received the Stahl swaging tool and the cutter today.  So, I'll be swaging away as soon as I get the time.

Dave Nyce