Where to Find Screw-Type Terminal Blocks?

Discussion in 'Rocketry Electronics and Software' started by bronicabill, Dec 4, 2019.

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  1. Dec 4, 2019 #1

    bronicabill

    bronicabill

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    I need to purchase a pair of 2-contact screw-type terminal blocks to complete my ebay. I used to drive over to my local Radio Shack to buy such things, or one of the two excellent electronics supply stores in town. Unfortunately ALL of those are now out of business, so I'm stuck mail-ordering something that's gonna cost more to ship than the actual product!

    Where are you guys buying stuff like this now? Thanks!!!
     
  2. Dec 4, 2019 #2

    tOD

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    IMG_20191204_041542.jpg IMG_20191204_041542.jpg
    I got these from DigiKey. You're right though, shipping is more than the product.
     
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  3. Dec 4, 2019 #3

    Wayco

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    I get my TB's from Mouser Electronics. They are the small green European style that fit nicely on smaller avbay lids. Just bought 20 four pin TB's for $27.77 total. $18.18 for the TB's and $7.99 for shipping.
    Mouser.com part # 651-1984633
     
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  4. Dec 4, 2019 #4

    Buckeye

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  5. Dec 4, 2019 #5

    BradMilkomeda

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    I have been directly connecting to my altimeter, but for my current project I’m going to be using terminal blocks. I have them from McMaster Carr along with other nuts and bit. Here is the part https://www.mcmaster.com/7618K613
     
  6. Dec 4, 2019 #6

    SammyD

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  7. Dec 4, 2019 #7

    Scrapmaster87

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    Last edited: Dec 4, 2019
  8. Dec 4, 2019 #8

    Johnly

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    I think I have a bag of these somewhere in my collection of electronics and parts.
    I'll start looking.
     
  9. Dec 5, 2019 #9

    g.pitts

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    DigiKey is your friend for any connector needs you may have (and then some). That’s where my e-bay connectors are coming from.
     
  10. Dec 5, 2019 #10

    tOD

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    I noticed after I posted, these are made in USA
     
  11. Dec 5, 2019 #11

    rewilfert

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    How do you connect the wires to the pins on the bottom? Do you just glue the block to the avbay lid?
     
  12. Dec 5, 2019 #12

    amiliv

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    Notice the hole in between each pair of terminals. It's for the screw. Or you can glue them. Or do both.

    Or are you are asking about making connection from the inside of the AV bay to the terminal outside it?
     
    Last edited: Dec 5, 2019
  13. Dec 6, 2019 #13

    rewilfert

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    Those blocks are for mounting to a PCB, correct? I was wondering how you attached the wires from the altimeter to them. I'm referring to the Mouser.com part # 651-1984633.
     
  14. Dec 6, 2019 #14

    g.pitts

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    That is correct - that particular connector is a through-hole termination intended for assembly onto a PCB. Some will solder wiring directly to the through-hole leads on the connector. Getting the wires into the electronics bay would require either a series of clearance holes or a milled slot so that the wires could be passed through. The presumption is that you'd want to decouple the environment of the electronics bay from that outside the electronics bay to avoid contaminants.

    I had an idea of fabricating a PCB design as the bulkheads of the electronics bay, which would allow the electronics bay wires (for the charges) to be directly soldered into that PCB, and traces would make the electrical connection to the leads on the Phoenix connector. That would provide a nice environmental seal for the electronics bay. That idea is definitely overkill, however. Just a passing thought.
     
    Last edited: Dec 6, 2019
  15. Dec 6, 2019 #15

    rewilfert

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    That would be similar to what the Avionics Bay Kit shown here does:

    https://www.featherweightaltimeters.com/av-bay-components.html
     
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  16. Dec 6, 2019 #16

    g.pitts

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  17. Dec 6, 2019 #17

    Wayco

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    Pictures are worth a thousand words:
    [​IMG]

    With fiberglass avbay lids, I drill single holes for each pin. If they are metal, I drill a big 1/2" hole and fill it with epoxy, then drill the smaller holes through the epoxy.

    [​IMG]

    Thread the tinned wires through the holes and solder them to the pins. This was on a carbon fiber lid, so I added a bit if heat shrink to the wires. When I seat the block down, I add a bit of hot glue to the lid to hold them in place.
     
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  18. Dec 6, 2019 #18

    MikeyDSlagle

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    I use the white ones like in post #7. A #6 machine screw threads nicely into the hole and holds it tight. They are cheap and easy to replace if they rust on ya. I have used the PCB mount as well..once; and pretty much the exact way as Wayco demonstrates above. They work but a little more difficult to mount and replace. If your tight on space they are an option though.
     
  19. Dec 6, 2019 #19

    amiliv

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    Ah. Those are terminal blocks for soldering onto PCB. I thought you were asking about terminal blocks like those tOD posted in comment #2 above.

    A nice, maintainable way of routing electrical connection from one side of the bulkhead to the other is short bolt screwed through the bulkhead, nut and two washers. Add o-rings if needed for seals. Crimp ring terminals to the wires. I've only a photo of a very fancy SMT Designs bulkhead handy, but you can see the general principle on it and it'd work with a plain bulkhead too. The wires from the altimeter (the two wires on the sides) terminate on the bolts on the inside of the bulkhead. You could connect e-match to the bolt on the outside directly (it'd act as terminal), or you can have terminal block like the one from comment #2 secured to the outside of bulkhead and have short wire from bolt to the terminal (same as the inside connection), and then connect e-match wires into the other side of the terminal.

    IMG_20191001_215010.jpg
     
  20. Dec 6, 2019 #20

    BradMilkomeda

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    On nice thing about the white terminal blocks is that the conductive components are recessed to prevent a short. I can conceive Mr Murphy causing a quick link or a swivel to short across exposed screws. As with many things in our hobby the proper use of some masking tape can mitigate this problem.
     

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