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quadrod
04-16-2016, 10:02 PM
Does any one know what pressure is needed to swage ends on 3mm cable? Or how much compression is needed for the crimp?

JoeLee
04-16-2016, 10:44 PM
I think it's going to depend on the manufacturer of the crimp fitting. It's usually recommended that you follow their instructions and use their crimp dies and tool. I would start looking here.

http://www.nicopress.com/products/

JL...............

lakeside53
04-16-2016, 10:50 PM
The handheld cable-end crimper I use for 1/8th (for wire railings) is 16 ton. Wouldn't want much less. This turns a round stainless ferrule into a hexagonal crip. Definitely use the recommended dies matching the ferrule.

J Tiers
04-16-2016, 11:08 PM
The real test is the pull-out test, where it fails.

With consistent cable, consistent ferrules, and consistent crimp height after crimping, you can pretty well guarantee the pull-out tension. The manufacturer will have that for their tool and ferrules.

For some ferrule off the internet, and a tool from somewhere else, who knows?

quadrod
04-16-2016, 11:51 PM
I was going to make my own dies and ferrules. The online instructions don't seem to give the amount of compression on the ferrules.

ahidley
04-17-2016, 12:27 AM
I just crimped on some #4 welding cables and I noticed this: there are several hundred strands in the cable. This allowes it to bend easily. When it bends the strands slide a little to allow the bend to form. If the end of the cable is crimped tight enough to not allow any strands to move then its crimped just tight enough. This mackes the cable impossible to flex for an inch or two after the crimp. Try to achieve that at a minumum.

Mike Amick
04-17-2016, 12:40 AM
When I was hang gliding a lot, we always did our own cables. Used one of those
nico presses that looks like a brake pipe flaring tool. Just use the right size nico in
the right hole and tighten the bolt. Good to go.

You can imagine how important we thought the wires were on our gliders. Never even
heard of a problem.

Wouldn't want to have to do a BUNCH of em with that tool .. but .. a half dozen or
so wasn't too bad.

JoeLee
04-17-2016, 09:10 AM
I just crimped on some #4 welding cables and I noticed this: there are several hundred strands in the cable. This allowes it to bend easily. When it bends the strands slide a little to allow the bend to form. If the end of the cable is crimped tight enough to not allow any strands to move then its crimped just tight enough. This mackes the cable impossible to flex for an inch or two after the crimp. Try to achieve that at a minumum. The OP isn't talking about electrical cables, but I know exactly what you mean with the fine stranded welding cable. With wire rope you will notice that stiffness close to the crimp fitting but it's not as pronounced as it is with the electrical cable.

JL................

wierdscience
04-17-2016, 10:15 AM
Cable swage go/no go gauge-

http://www.aircraftspruce.com/catalog/topages/gonogo.php

quadrod
04-17-2016, 11:08 AM
Thanks wierdscience. I think I have found what I need. It looks like for 1/8" cable you want and .250 ferrule and about .032" of crimp or a compression of .218"

Paul Alciatore
04-17-2016, 11:10 AM
The companies that make these have done the research and testing, destructive testing, to ensure that their combination of ferrules and dies will work properly. They have probably spent thousands, tens of thousands, perhaps hundreds of thousands of dollars in this process. They know that with the alloys they use and other manufacturing steps for making their ferrules, their dies will make a reliable crimp with a certain strength that they can guarantee. They probably have a continuing test program to ensure reliability. And you expect them to just give away that knowledge with the instructions? That would not be a good business model. And if they omitted or misstated just one small detail, they would probably be liable for any damages caused by ferrules and dies made by others. Oh, and they will have millions of dollars in liability insurance.

A proper crimp on wire, weather mechanical of electrical, is a delicate balance. If there is too little pressure applied, then the wire will just pull out. But crimping causes metal to FLOW and both the ferrule AND the wire will experience this. So, too much deformation can cause the wire to be weakened at the point of the crimp and it can break in half there. I have seen both modes of failure. You have to get it at that proper, in-between point for the maximum strength and reliability.

If you want to get into that, ante up. For me, I will just buy the ferrules and dies when I need them.

And YES, I have seen the results of some efforts to use incorrect or makeshift crimping tools. They swore that the crimps were OK. Upon inspection I found that quality was all over the place: some OK and others were horrible. Some of them actually just fell apart from handling.

You can get cable fasteners that are tightened by hand. I would suggest them and using the proper torque when assembling them.

One more thing, most dies are made to work properly if they are FULLY CLOSED. The pressure used is not measured, it is just enough to ensure that the die was fully closed. The die is carefully made to ensure that the proper degree of deformation has occurred when this happens. The die will function over a wide range of actual pressures from somewhat less than the recommended value to quite a bit more.




I was going to make my own dies and ferrules. The online instructions don't seem to give the amount of compression on the ferrules.

J Tiers
04-17-2016, 11:19 AM
+1 on that

You don't seem to have mentioned what you need to crimp cables for... Maybe its something totally non-critical.

As mentioned by Paul A, and above by me, the crimp amount is totally irrelevant.................................... irrelevant UNLESS you know that with THAT SPECIFIC CONTROLLED SIZE of sleeve, to the thou, AND a specific cable, AND a crimp shape and final height, that the result is a crimp of the required strength.

You do NOT know that unless it has been tested. And, you should know the effect of small variances from that crimp shape and height, so that you are sure of your tolerance zone.

If the crimp is the right height, bit NOT width, then you don't know how the metal flowed. The crimp is presumed defective.

If you are just doing tent cable, maybe that's good enough. But for anything important, a "high confidence" crimp, trying to do it with home-made crimping dies that are not made to dimension, and are not known to produce a good crimp, is just plain silly when the right, proven dies etc are available at what is, in the long run, a low cost.

If you don't care, or if you can test the strength, well, fine, do what you like. You've been told, so it's now on you. You cannot claim you didn't know.

wierdscience
04-17-2016, 01:43 PM
Aircraft and wire rope have standards for the swage.There are military and civilian standards for terminations in both.The use of a go/no go gauge insures the finished swage conforms to the spec regardless of manufacture.A proper swage is gauged as fitting the go gauge with no flash or ovality present.

Think it through,what sort of a disaster would it be if every manufacture had their own spec?Imagine having to inspect and certify terminations in the field with 50 different mfgs and 50 different standards,not pretty or practical.

Electrical connections are a different animal entirely and the systems used there have no bearing on terminations made for aircraft or wire rope terminations.

Bob Fisher
04-17-2016, 02:23 PM
In a former life I used to crimp seat belt buckles onto wire cable. We used split hexagonal dies with radiused corners and a 90 ton Ironworker to crimp them. As you can imagine, there is no room for compromise here. The only acceptable tensile test was a broken cable or buckle. My point is that you need to be able to test for your conditions to establish the size and shape of your dies. Bob.

garyhlucas
04-17-2016, 02:31 PM
If you want ultimate strength with almost no possibilty make a Flemish Eye. You unwrap 3 out of the 7 outer wire bundles and weave them back togther in the opposite direction. The ferrule then just traps the loose ends. Strength is the same as the cable.

quadrod
04-17-2016, 03:36 PM
It is not an air craft control cable. It is for a parking brake cable on the car I'm restoring. I thought there might be some sort of printed data out there similar to what can be found in machinery hand book. Did not mean to stir anything up. I am planing to test the strength when done. It is after all a hand operated lever and cable assembly. Don't have the room for a flemish eye. I could just splay the end of the cable and silver solder in place.

J Tiers
04-17-2016, 04:46 PM
Aircraft and wire rope have standards for the swage.There are military and civilian standards for terminations in both.The use of a go/no go gauge insures the finished swage conforms to the spec regardless of manufacture.A proper swage is gauged as fitting the go gauge with no flash or ovality present.

Think it through,what sort of a disaster would it be if every manufacture had their own spec?Imagine having to inspect and certify terminations in the field with 50 different mfgs and 50 different standards,not pretty or practical.

...

That would not seem to pose even the slightest problem.

All that is necessary is to have on the print the manufacturer(s) selected for use, and then you know what tool is required. They will be listed on the print, most likely anyhow. You get that tool and use it, checking per the spec for the crimping system. No issue whatever. Keep the tool calibrated and make cables.

Black_Moons
04-17-2016, 05:06 PM
It is not an air craft control cable. It is for a parking brake cable on the car I'm restoring. I thought there might be some sort of printed data out there similar to what can be found in machinery hand book. Did not mean to stir anything up. I am planing to test the strength when done. It is after all a hand operated lever and cable assembly. Don't have the room for a flemish eye. I could just splay the end of the cable and silver solder in place.

You'd be amazed how many old car parts are still available today.

Somehow I don't think home made crimps is a good option in this case as there is a definitely risk if things went wrong.. I would kinda recommend lead soldering to brass over home made crimps. At least soldered ends is a common technique for motorcycle brake cables and throttle cables, so it has some history of being used in safety critical applications.

I would not silver solder (braze), because I think the heating might alter the wire ropes characteristics. Lead soldering is not hot enough to do that.

I'll note iv broken the parking brake cable in a car while working on it (removing the dash and had to take it outta park on a slight hill so I set the brake really good.. a little too good.. Foot parking brake mind you, so much more force then a hand brake)

wierdscience
04-17-2016, 06:09 PM
That would not seem to pose even the slightest problem.

All that is necessary is to have on the print the manufacturer(s) selected for use, and then you know what tool is required. They will be listed on the print, most likely anyhow. You get that tool and use it, checking per the spec for the crimping system. No issue whatever. Keep the tool calibrated and make cables.

There is no calibration,the dies wear and are discarded.The gauge is the tell tale,it's either swaged down enough or it's not,no grey area and no paperwork to chase.

J Tiers
04-17-2016, 07:14 PM
There is no calibration,the dies wear and are discarded.The gauge is the tell tale,it's either swaged down enough or it's not,no grey area and no paperwork to chase.

OF COURSE THERE IS CALIBRATION. For goodness sake it is AEROSPACE APPLICATION.

Calibration consists of verifying that the die set and crimper make crimps of the right height, etc. QC also checks them, no doubt. But I will freaking guarantee that someone has a record of that tool and that serial die and the crimp dimensions it was tested to make.

If you have ever worked with a Nicopress tool, there is a setting on it that affects the crimp. I've set them per the Nicopress directions, I KNOW.

wierdscience
04-17-2016, 08:43 PM
OF COURSE THERE IS CALIBRATION. For goodness sake it is AEROSPACE APPLICATION.

Calibration consists of verifying that the die set and crimper make crimps of the right height, etc. QC also checks them, no doubt. But I will freaking guarantee that someone has a record of that tool and that serial die and the crimp dimensions it was tested to make.

If you have ever worked with a Nicopress tool, there is a setting on it that affects the crimp. I've set them per the Nicopress directions, I KNOW.

I'm not talking about Nicropress,I'm talking wire rope tooling,different animal.

J Tiers
04-17-2016, 11:48 PM
I'm not talking about Nicropress,I'm talking wire rope tooling,different animal.

Say what?

Nicopress IS wire rope tooling. In the size range of the OP.

Yes they do other stuff also, but they do wire rope tooling, just not for large stuff. They have aluminum sleeve for general non-critical stuff, but the copper sleeve stuff is for when you want load rated.

flylo
04-18-2016, 12:05 AM
Cable swage go/no go gauge-

http://www.aircraftspruce.com/catalog/topages/gonogo.php

I use the bolt cutter style with that go-no go gauge, do double ferrules douhle crimps & leave 1/8" of cable showing so I can easily see a problem on preflight.

aribert
04-18-2016, 07:41 AM
quadrod:


I do not disagree with any of the advice or cautionary statements in earlier posts. That said; I was in a similar quandary when I swapped a convertible body onto my Triumph coupe - I needed the brake cable to be several inches longer because the routing changed a bit. I bought my ferrule from McMaster-Carr and made my own swaging tool I used a couple pcs of 3/4 inch key stock (it was laying close to the mill), clamped the key stock together and milled a hole the two pcs at the split line. I pocketed some small ball bearings (1/8 or 5/32, don't remember) to dimple the ferrule - similar to the dimples on the OEM cable ferrule. I used my 30T press but did not need all that much force. Camera phone image of the swaged ferrule in place: http://i290.photobucket.com/albums/ll272/aribert/Triumph/20150606_2115191_zpslhxwrreo.jpg


"It is for a parking brake cable on the car I'm restoring. I am planing to test the strength when done. ...a hand operated lever and cable assembly. Don't have the room for a flemish eye.

Paul Alciatore
04-18-2016, 02:01 PM
And without destructive testing, neither you, nor I, nor anyone else knows if that crimp is good or bad.

Even if you did do destructive testing of a similar one, you still know very little about that one. A single test does not produce confidence.




quadrod:


I do not disagree with any of the advice or cautionary statements in earlier posts. That said; I was in a similar quandary when I swapped a convertible body onto my Triumph coupe - I needed the brake cable to be several inches longer because the routing changed a bit. I bought my ferrule from McMaster-Carr and made my own swaging tool I used a couple pcs of 3/4 inch key stock (it was laying close to the mill), clamped the key stock together and milled a hole the two pcs at the split line. I pocketed some small ball bearings (1/8 or 5/32, don't remember) to dimple the ferrule - similar to the dimples on the OEM cable ferrule. I used my 30T press but did not need all that much force. Camera phone image of the swaged ferrule in place: http://i290.photobucket.com/albums/ll272/aribert/Triumph/20150606_2115191_zpslhxwrreo.jpg


"It is for a parking brake cable on the car I'm restoring. I am planing to test the strength when done. ...a hand operated lever and cable assembly. Don't have the room for a flemish eye.