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  • Author Author: dubbie
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My First Ever Crimping Experience

dubbie

For my Sand Based Cat Detector (Cat Detector Using Sand #2 : The Implementation ) I used a lead acid battery with spade connections. I have never properly used spade connections before (I usually use crocodile clips or solder directly) so I thought this would be a good time to start as I am working my way towards an outdoor mobile robot and robust and reliable connections are essential. Not really knowing much about making spade or crimping connections I decide that the best approach would be to buy some and just try it out. I have wanted to crimp for some time so rather than find out about it I just blundered in and bought something. I do not expect to do much crimping in the future so just looked online and bought the cheapest set I could find that seemed to do what I wanted.

 

 

I used deep learning to update my natural neural networks in my head, basically I just stuck some wire inside the crimpets (or connectors) and tried to make good connections with the wire using the crimping tool. Initially there was little success as the tool I obtained did not come with any instructions what-so-ever. The crimpets would not stay on the wire while I attempted to use the crimping tool and several crimpets were harmed in this process.

 

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It took me several attempts to work out that the tool I had purchased did not do any folding of the little tabs on the crimpets. Once I had worked this out and folded over the ;little tabs using some pin nosed pliers I was able to make some good crimped connections. I'm not sure if it uses cold-welding or just mechanical interference to make a good physical and electrical connection, but they seem to work, so all is good.

 

Dubbie

  • in reply to shabaz

    Good news, it looks like the cheap used custom-variant DMC tool can be handy for crimping the centre pins of small RF connectors.

    The particular tool is called 'DMC MH800' and it looks like it is made for a BT (British Telecom) specific connector. There appear to be dozens of these used MH800 tools on ebay, for £10 upward.

    I think the BT connector must have been SMA connector-sized or similar, and seems set up to approximately crimp well enough for ballpark RG316 centre conductor wire. However, the MH800 tool has the following issues:

    1. The positioner (which determines how far down the shaft of the pin to crimp at) is preset, and is not useful for anything other than the (unknown) BT connector

    2. The MH800 tool has no adjustment dial for crimp depth (how much the pin will be crimped), that part of this tool is blanked out with a sticker.

     

    The good thing is that the tool is very hackable. It was possible to disassemble it without any pieces flying off, all with a few Imperial hex keys. To resolve issue (1) it will be easy to make a custom positioner (either with some simple metal or plastic work, or could even be 3D printed).

    Issue (2) is a bit harder, but not insurmountable at all. I have an idea to find a circular piece of metal, and drill a hole slightly off-axis, and use a nut and bolt to make it act like a fixed cam almost. If that is done then it will work for pins even down to (say) approx 0.4mm outer diameter, at a guess. The normal adjustable DMC tool does a similar thing I think.. it has a dial control which is supposed to be lifted and rotated.

     

    I'll write up a blog post when I get it done (unlikely for at least a week or so) but in summary I think the tool will be useful for RF connectors of size SMA and smaller, once the two issues are resolved. The tool will not be useful for larger RF connectors, because of the shape of the four metal punches.. they are fairly pointy on this custom MH800 tool, and will just tear into larger pins (I tested with a BNC centre pin); I think it has to be for SMA or smaller connectors, RF or otherwise.

  • in reply to phoenixcomm

    I suspect the noise the computer made was similar to the stepper switches in telephone central offices facilitating connections.

     

    If your posts are an indication then you are mentally spry at 71. I celebrated my 59 today. I am just waiting for a supper of my favourite meal and then on to birthday cake. Burn the house down with that many candles lit.

     

    Where I come from, taking the the holy deity's name in vain is frowned upon. It is difficult to correlate Jesus and Jasus, as in Jasus, Mary and Joseph.

  • in reply to colporteur

    "Jasus,  a spiny lobster, or Jesus, most likely what you meant. I'm just older than dirt and coming up on 71. The first computer I built was in high school, I took over two years and was built out of RTL logic, nothing off the shelf except for the relays (surplus, form h, and the transistors 2N404 my dad worked for RCA and well that where they came from. It had an 8-bit memory one relay per bit, plus a relay for reading, a relay for write, and a lock relay. Add I had 2 rotary stepping relays for addressing. for input, I had a rotary telephone dial, and toggle switches for data. It could ADD, SUBTRACT. MULTIPLYING AND DIVISION was accomplished by shifting right or left. The thing made a racket when it worked.

  • in reply to phoenixcomm

    Your commentary has the ability to pull me back in time to say

    "Jasus, I know what that is....wasn't it used in ....."

  • in reply to Andrew J

      yes I know my first pc hand-built running ms-dos in the late 70 's I pickup up a TTY 35 paper tape and that jazz but before that, I had an IBM 129 that I got for free. But it spoke EBCDIC to the card when you typed, but In verify / read mode I ran I through an 8080  to generate ASCII. LOL

    ~~Cris