Previous in Forum: Pressure Relief Valve Settings   Next in Forum: Difference Between Unbalance and Imbalance
Close
Close
Close
14 comments
Participant

Join Date: Oct 2014
Posts: 3

Determining Correct Crimp Procedure

10/21/2014 2:33 PM

Hi,

Firstly, this is my first post here. Glad to be part of the community!

I am trying to determine how to calculate the correct crimp needed to ensure that the crimp doesn't fail under load. Essentially, can I calculate how much the inner diameter needs to shrink in order to ensure a the connection will resist a certain amount of pull force? I am using stainless steel rope and a brass socket crimp, but the type of material for the socket can change. I really appreciate the help!

Liam

Register to Reply
Pathfinder Tags: Crimp Pull force
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru

Join Date: Apr 2014
Posts: 1869
Good Answers: 67
#1

Re: Determining Correct Crimp Procedure

10/21/2014 4:10 PM

See if this has the info you need [pdf].

Register to Reply
2
Guru

Join Date: Oct 2008
Posts: 42308
Good Answers: 1666
#2

Re: Determining Correct Crimp Procedure

10/21/2014 5:44 PM

eII has provided a good reference.

All too often people think that only mathematical calculations will allow you to arrive at mechanical solutions.

Far more information than you have provided would be needed to determine, mathematically the correct crimp pressure.

Size, material of construction of wire rope and crimp mechanism, crimp tool used, pull-out strength required, environmental considerations and service conditions (straight pull single thickness crimp or looped double thickness crimp would all need to be taken into account.

Brass tells me that the pull-out load is rather small.

I'd go to the wire rope/crimp/crimp tool suppliers and give them your requirements and ask for advice.

Welcome.

Register to Reply Good Answer (Score 2)
Participant

Join Date: Oct 2014
Posts: 3
#3
In reply to #2

Re: Determining Correct Crimp Procedure

10/21/2014 6:29 PM

The wire rope specified in the guide is large compared to what I am using; I am restricted to 0.018" diameter rope. Will it act more like a wire in this case? I am looking at using electrical wire crimp sockets.

Register to Reply
Guru

Join Date: Oct 2008
Posts: 42308
Good Answers: 1666
#4
In reply to #3

Re: Determining Correct Crimp Procedure

10/21/2014 6:46 PM

20 questions is not fun.

You haven't told the forum what you are trying to accomplish.

Going to ss wire web sites tells me that the wire is good for 40#.

Going to a crimp socket site may give you similar pull-out information.

You could crimp this with a wire crimp tool, by hand. Why waste time calculating anything.

Register to Reply
Guru

Join Date: Apr 2014
Posts: 1869
Good Answers: 67
#5
In reply to #3

Re: Determining Correct Crimp Procedure

10/21/2014 7:02 PM

Is there any other information you would like to add?

0.018" diameter rope is little different than stranded wire of the same or similar diameter. What stranded-wire gauge is closest to 0.018"? Find crimp terminals for that size wire, a crimping tool for that size crimp and off you go, hitting the pavement running. No calculations required.

Register to Reply
Guru

Join Date: Oct 2009
Location: sometimes Wales,UK.. was Libya, now Oman!
Posts: 1715
Good Answers: 116
#6

Re: Determining Correct Crimp Procedure

10/22/2014 12:21 AM

You want to crimp wire? Why not use a certified company who will give you a certificate that its good to go, that would save you an whole world of heartache come inspection time, or worse if it fails under load.

Then you said in a further answer..

The wire rope specified in the guide is large compared to what I am using; I am restricted to 0.018" diameter rope. Will it act more like a wire in this case? I am looking at using electrical wire crimp sockets.

Now this is confusing..... are you looking to crimp wire rope or electrical cable? OR use electrical crimps to crimp wire rope?

As for cable crimps taking a load, they can! It's called current! Any mechanical load on a electrical crimp and electrical cable combined is NOT recommended. As for using cable crimps to crimp wire rope.. that is a dangerous thought, as again the crimps are not designed to take load due to the material they are made from.

So it's your first post, and a tip here is to be clear, state exactly what you have done so far and be open about your mistake too!

As for calculating.. Na.. waste of time, when there are so many companies that will do a good job for you, issue you a certificate of safety and use the correct material and processes.

__________________
The square root of nothing is what you make it!
Register to Reply Score 1 for Good Answer
Guru
Australia - Member - New Member Engineering Fields - Mechanical Engineering - New Member

Join Date: Sep 2006
Location: NSW Australia
Posts: 1088
Good Answers: 23
#7

Re: Determining Correct Crimp Procedure

10/22/2014 3:09 AM

Designs for crimping are based on empirical evidence rather than calculations.

__________________
Dont get on to the roundabout if you dont know how to get off
Register to Reply
Guru

Join Date: Jul 2007
Posts: 4448
Good Answers: 143
#8

Re: Determining Correct Crimp Procedure

10/22/2014 5:49 AM

It sounds like you might want to look at what folks do for safety cables. Google safety cable crimping, or call somebody like Bergen for help.

__________________
"Well, I've wrestled with reality for 35 years, Doctor, and I'm happy to state I finally won out over it." Elwood P. Dowd
Register to Reply
Power-User

Join Date: Mar 2011
Posts: 238
Good Answers: 14
#9

Re: Determining Correct Crimp Procedure

10/22/2014 7:25 AM

Amp/Tyco would have a lot of info for you regarding pull out force requirements. Many crimpers I calibrate have pull out specs as opposed to dimensional specs.

Register to Reply
Guru
Hobbies - Fishing - Old Salt Hobbies - CNC - New Member United States - US - Statue of Liberty - New Member

Join Date: Mar 2007
Location: Rosedale, Maryland USA
Posts: 5198
Good Answers: 266
#10

Re: Determining Correct Crimp Procedure

10/22/2014 8:06 AM

Whats the load? Is it electrical or mechanical?

Heat elements use stainless steel wire leads. Which I recommend stainless terminal ends. If being used for electric. Dissimilar metals expand and contract when heated. Which causes the crimp to fail. I would also if crimping stainless steel terminal to stainless steel wire use hydraulic crimper. Had too many that have been hand crimped fail.

If mechanical get a compression sleeve for the wire. A 1/32 with the wire loop thru should be close. Might want to double them up.

__________________
Life is not a journey to the grave with the intention of arriving in a pretty, pristine body but rather to come sliding in sideways, all used up and exclaiming, "Wow, what a ride!"
Register to Reply Score 1 for Good Answer
Guru

Join Date: Nov 2012
Posts: 633
Good Answers: 13
#11

Re: Determining Correct Crimp Procedure

10/22/2014 9:35 AM

Check out Nicopress.....I've been using their products for 30 years with SS cable through .25in dia. for 30 years with no failures. They supply a 'go-nogo' gage for each crimp type.

Register to Reply
Guru

Join Date: Mar 2007
Location: City of Light
Posts: 3943
Good Answers: 182
#12

Re: Determining Correct Crimp Procedure

10/22/2014 12:48 PM

I was involved a couple of years ago in the design of an intelligent tool for crimping of electrical connections (for automotive and airborne systems). Those are tools with 4 plungers at 90° and are controled not in pressure but in deformation of the socket. For such a small diameter I think it would be of interest to look at this technology.

I can only say that the local pressure has to be high enough to destroy the oxyde layer at wire and socket surface and generate a cold metal to metal bond.

It is not only based on friction as we are accustomed in machine design it is a more complex and surface related connection. Of course those connections were thought for electrical continuity so that conditions were much more severe.

Register to Reply Score 1 for Good Answer
Participant

Join Date: Oct 2014
Posts: 3
#13

Re: Determining Correct Crimp Procedure

10/23/2014 11:53 AM

Great, thanks for everyone's help. Sorry if I was confusing but I think your answers led me toward the correct solution.

Liam

Register to Reply
Power-User

Join Date: Oct 2014
Posts: 143
Good Answers: 4
#14

Re: Determining Correct Crimp Procedure

11/02/2014 4:02 PM

For a safety-critical crimping of steel rope I went to the rope manufacturer, had the crimp sleeves crimped there on a hydraulic press and on a sample of the same bobin an identical sleeve was pressed and a destructive pull test was performed on that 1:1 sample. Process parameters (crimping force, used press, dice type and #, etc.) and laboratoy test results were documented.

Depending on the reqiuired safety level your mileage will vary.

Register to Reply
Register to Reply 14 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

brich (1); europium mkII (2); garth (1); geraldpaxton (1); harley (1); LiamQB (2); lyn (2); nick name (1); ozzb (1); Plimos (1); TVP45 (1)

Previous in Forum: Pressure Relief Valve Settings   Next in Forum: Difference Between Unbalance and Imbalance

Advertisement