PDA

View Full Version : Slightly OT: Looking for small wire splices...making them is tedious



Rif
02-23-2010, 10:22 AM
Hello,

I am working on a project where I need some tiny, uninsulated, wire splices. Last night, I made about 8 of them, out of brass, with the following dimensions:

Length: 0.100
Outside Diameter: 0.080
Inside Diameter: 0.052

While they do not really need to be made out of brass, they need to be able to be crimped in order to splice nichrome wire with 20 gauge stranded wire. Since the device they are being used on is small, they need to be small too.

I wouldn't have a problem making them, however, similar size mass produced parts are usually less than 10 cents each so it doesn't make economic sense for me to make them. Also, after I cut one off, I have to go on a treasure hunt in order to figure out where it landed.

I have seen some electronic devices with something similar in them; but, I don't know what they could be called. I have tried looking for ferrules, splices, sleeves, and I still haven't found anything with those dimensions. The closest I found where ferrules; but, they were around 1/4 inch long.

Thanks in advance for any advice.

Regards,

Brian

Duffy
02-23-2010, 10:30 AM
Hypodermic tubing. Someone posted a site that sells all sizes in stainless steel.

knudsen
02-23-2010, 10:32 AM
Check fischer scientific, they have HPLC tubing in that range. Definitely in SS, but you might find copper. uBore tubing is smaller on the OD, standard HPLC tubing is 1/8" OD. uBore is thin enough to crimp easy, standard will crimp with force.

bruto
02-23-2010, 11:01 AM
The smallest ferrules I've found are for 24 awg wire, 5 mm. long. Mouser electronics has these.

MotorradMike
02-23-2010, 11:37 AM
Many electronic connectors use machined pins which are crimp type. We use them for splicing, just cut the connector part off and use the barrel.

It's best to have the right crimp tool but...


Mike

Rich Carlstedt
02-23-2010, 01:16 PM
Just buy some 2 mm or 5/64 brass tube
such as
http://www.specialshapes.com/brasstubing.asp?product=006

Take a block of Acrylic and saw down into it with a very fine razor saw (Exacto) from a hobby shop.
Then drill a cross hole the proper size for the tube, through the saw cut.
Grind the block down until the sawcut is the desired length to the edge.
Feed in the tube , and cut with a few strokes, then push the tube in again and eject the finished part.
Rich

Weston Bye
02-23-2010, 01:30 PM
Hers's how I made a similar part:

http://bbs.homeshopmachinist.net/showthread.php?t=39588&highlight=a+small+production+job

Bruce Griffing
02-23-2010, 02:07 PM
Google beanie crimp connectors - this type might me small enough for your application

Rif
02-23-2010, 02:36 PM
Hello,

Since it looks like I will have to cut them to size, regardless, I think the best option is probably for me to cut them out of brass tubing as it saves me the drilling time.

McMaster has 3/32 brass tubing at $12.24 for 15 feet, in one foot lengths. The OD is 0.0937 and the ID is 0.066. This should be close enough for the application.

Thanks!

Brian

beanbag
02-23-2010, 03:04 PM
many hobby shops and hardware stores sell small diameter brass tubing

knudsen
02-23-2010, 03:09 PM
Or copper.

Sliding a smaller diameter solid brass in the part your cutting slid in just past the cut mark saves some deburr time.

knudsen
02-23-2010, 03:22 PM
This might be worth exploring: http://www.labx.com/v2/spiderdealer2/vistaSearchDetails.cfm?LVid=7041452

Territool is the best of this type, but it's $250 from fischers. Two quick spins, snap it, you're done.

I used an abrasive cut off with a built in deburr tool, but I think it would be cost prohibitive and clog the wheel with brass or copper. Good on stainless.

form_change
02-23-2010, 09:47 PM
Have you thought about going to a fishing tackle shop? They have all sorts of crimps there for doing (stainless) trace and may have something you can use. I bought some myself for another project where I have a hundred plus stainless wires to work the valves on a pipe organ.
One tip I would give you though is to buy the best crimping pliers you can afford - the cheap ones soon become a pain in the wrist.
Michael

darryl
02-24-2010, 12:01 AM
I just saw what was probably brass plated steel tubing pieces at a dollar store in the craft section. I almost bought a bag of them, but instead I'll remember they're there if I ever need any small pieces of tubing like that. The size was about like you've described, and length looked to be about 3/4 inch or so. I think they are decorative pieces made to be threaded onto string along with beads.

I did the math in my head- inch for inch that was about a third of the price you'd pay for brass tubing in a hobby shop, and I think that for your application this would be better than brass.

Paul Alciatore
02-24-2010, 01:49 AM
Many electronic connectors use machined pins which are crimp type. We use them for splicing, just cut the connector part off and use the barrel.

It's best to have the right crimp tool but...


Mike


"...But..."

No, No, NO, NO, NO! No "buts" about it, it is absolutely vital to use the proper crimp tool. PERIOD. I have had to re-do too many of these improperly crimped connections.

If you are going to crimp, use the right tool.

Paul Alciatore
02-24-2010, 02:08 AM
You said 20 gauge, stranded wire. Heck, that is fairly large. Crimp terminals are made for 24 and even 26 gauge. Just get some uninsulated ring or forked terminals for 20 gauge or slightly larger if needed, and crimp them with a standard, proper crimp tool. Then use a nice sharp pair of diagonal cutters to cut off the ring or fork. I have done this many times and it works quite well.

Done! And you used all proper materials and tools. Should make a reliable connection every time.

Rif
02-24-2010, 11:35 AM
Hello,

Thanks again for all of the input.

One of the problems is that the 20 gauge wire is connected to a 31 gauge piece of nichrome wire that is on a part that is only 0.550 long and 7/16" wide. So, I am trying to avoid using connectors that are bigger than the part.

Oh, and the crimping tool is not a problem. I either have or have access to crimping tools. I am using a crimping tool for uninsulated wire.

Thanks,

Brian

RKW
02-24-2010, 12:05 PM
If you are going to crimp, use the right tool.

Agreed, but some of those crimp tools can cost hundreds and are supposed to be calibrated every so often, at least for industrial or commercial use. And I'm not talking about automated crimpers here, but hand operated crimpers. This type of crimper will create a highly reliable connection but is out of reach for the average person.

Just a few examples here (http://www.thingsforacftsupport.com/crimpersbackpage.html).

gmatov
02-25-2010, 12:06 AM
Such crimpers I have a couple of which I do not need. No idea the value. Offers, and I will have to go check the range tomorrow?

Cheers,

George

12teethperinch
02-25-2010, 12:24 AM
I agree with the poster who suggested a fishing supply shop. I had some small stainless ones for making leader lines that I think would work for you. Heres a link to something like I am suggesting http://images.google.ca/imgres?imgurl=http://www.spearitco.com/images/products/CRIMPS.jpg&imgrefurl=http://www.spearitco.com/index.php%3Fmain_page%3Dproduct_info%26cPath%3D66_ 72%26products_id%3D248&usg=__iuRQAvZFmQdnhG-h9lwmQ9e4C_o=&h=500&w=500&sz=33&hl=en&start=1&um=1&itbs=1&tbnid=EG7k-vQ2m9OacM:&tbnh=130&tbnw=130&prev=/images%3Fq%3Dfshing%2Bcrimps%26um%3D1%26hl%3Den%26 sa%3DN%26rlz%3D1R2GGLL_en%26tbs%3Disch:1

knudsen
02-25-2010, 12:35 AM
"...But..."

No, No, NO, NO, NO! No "buts" about it, it is absolutely vital to use the proper crimp tool. PERIOD. I have had to re-do too many of these improperly crimped connections.

If you are going to crimp, use the right tool.

Can't ya just make it fit?

Paul Alciatore
02-25-2010, 01:42 AM
Agreed, but some of those crimp tools can cost hundreds and are supposed to be calibrated every so often, at least for industrial or commercial use. And I'm not talking about automated crimpers here, but hand operated crimpers. This type of crimper will create a highly reliable connection but is out of reach for the average person.

Just a few examples here (http://www.thingsforacftsupport.com/crimpersbackpage.html).

I agree that there are crimp tools that cost many hundreds of dollars. I use some of them every day at work. And they are worth every cent.

But, for simple crimp terminals there are many very good quality crimp tools in the $10 to $30 range that will do an excellent job. There is no reason to use a pair of pliers which may even cost more. As for calibration, if you are doing tens or hundreds of thousands of crimps, yes they will wear and need to be checked and adjusted or replaced from time to time. But in the home shop, you will never get to that point. And even if you do, the proper tool will still do a better job than a pair of pliers or whatever.

I once saw a so-called professional using a pair of diagonal cutters to crimp terminals. He claimed that he actually knew just how much pressure to exert to make a good crimp without cutting the terminal in half. After he left, I checked and half of his crimps broke in half with only the slightest amount of handling. I replaced them all. My labor in replacing the terminals was about ten times the cost of the tool.

Black_Moons
02-25-2010, 03:55 AM
hahah. iv done crimping the incorrect plyer way before.. but I usally use a small jeweler flat head screwdriver + a tiny hammer to place a dimple in the crimped area to insure it can't pull the strands out, as just crimping it with needle nose plyers rarely gets it tight enough

J Tiers
02-25-2010, 08:56 AM
Paul.....

If he has to MAKE the crimp connectors, then by DEFINITION there is no "proper tool"..... and one of his tasks will be to create one, AND qualify it.....

Nichrome is a problem.... connecting to it is, anyway.