Stripping Coax tips

Discussion in 'Home Theater Projects' started by Chuck Paskovics, Sep 18, 2006.

  1. Chuck Paskovics

    Chuck Paskovics Stunt Coordinator

    Joined:
    Feb 26, 2002
    Messages:
    98
    Likes Received:
    0
    Trophy Points:
    0
    I just got my belden 7787a bundled coax, a stripper, and a crimpter in today. I bought a little extra wire to practice with. I've never done this before so i'm not sure what is supposed to be stripped and what is not.

    I'm connecting this to a one piece crimp style bnc connector.

    When I strip the wire, most of the braid seems to get stripped off too. Is this a problem? The aluminum under the braid stays intact. I haven't tried to crimp yet, just slid the wire on the connector. It seems to go on ok. I'm just concerned about all the braid getting stripped too. I've got the blade on the lowest setting, but it still clips about half the braid away.

    Any tips here? I've done a ton of searches to see how to do this properly, but no luck as of yet.
     
  2. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
    It’s working correctly. The braid is supposed to strip off. Don’t know how your BNC’s are supposed to work, but regular RF connectors have an internal sleeve that slips down between the black jacket and the electrolyte. ( I think that’s what it’s called, but I may have the name wrong – it’s the white covering for the center conductor, surrounded by the aluminum.) When you crimp the connector, the sleve, braid and aluminum will all have firm contact.

    Again, that’s the way it is with RF connectors. Can’t vouch for your BNC’s but if they’re designed for coaxial cable, they should be the same.

    Regards,
    Wayne A. Pflughaupt
     
  3. Leo Kerr

    Leo Kerr Screenwriter

    Joined:
    May 10, 1999
    Messages:
    1,698
    Likes Received:
    0
    Trophy Points:
    0
    BNCs are usually a bit different than RF connectors - more specifically, the "F" connectors.

    As an aside, it isn't "electolyte" - that's the stuff in capacitors. Unfortunately, now, I'm drawing a blank on--- DILECTRIC! That's it.

    Anyway, I've not worked with many "crimp" single-piece BNCs - the only single-piece BNCs I've used were "compression" where you strip the wire a bit, and then proceed to ram the connector on as hard as you can, and then the "crimper" works in-line, shortening the connector, rather than pinching the collar of the connector.

    Anyway, I digress yet again. But again, I've not worked much with single-piece BNCs. Most coax-stripping I've done is generally referred to as "quarter-quarter." This refers to the fact that when you strip the wire back, you want it to be in 6.3mm increments. (okay, okay, quarter-inch.)

    Anyway, when you strip the wire, you want the center wire to be free and clean of all the dilectric. This is rarely a problem. And, generally, you work the stripper so that the center-pin is a bit "long" - you can cut it back to a quarter-inch later with wire-cutters.

    Setting the next blade is usually a bit more troublesome. Ideally, it does NOT cut the braid, but just the outer jacketing. Generally, however, when you remove this outer part, there'll be a few bits of the braid that got cut off, but not to worry.

    Here's where it starts to get tricky, and your actual process varies depending on your connectors. In my 3-piece BNCs, the collar goes on first, slid back beyond the strip-zone. The center pin gets crimped after a good strip. Then the braid gets splayed just a bit, and the main piece goes on, inside the braid. Then the collar gets pushed back forward, pinching the braid down against the shaft, and then is crimped over it.

    With my single-piece compression plugs, the braid needed to be spread - ever-so-slightly so that it still fit within the outer piece, but didn't try to get fowled up with the rest of the stuff.

    So Chuck, the best tip I can give you is that you should have ordered a few extra ends to crimp onto your extra cable, too.

    Now, I've just checked up on the cable, and find it is the so-called "Mini" cable. I've never worked with this, it's never looked like fun. This stuff looks like a major PITA to work with. So when you get down to trying to do something with it, well, the best thing I can do now is just wish you luck.

    Leo
     
  4. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
    Hmm... That’s something I didn’t do before - check on the cable. The 7787 requires special connectors - it won’t accept the connectors made for standard coaxial. Hopefully whoever Chuck bought his cable from supplied him with the right connectors.

    Regards,
    Wayne A. Pflughaupt
     
  5. Leo Kerr

    Leo Kerr Screenwriter

    Joined:
    May 10, 1999
    Messages:
    1,698
    Likes Received:
    0
    Trophy Points:
    0

    Of course once I read "electrolyte" the real answer was just gone.. took me a long time to figure it out again!

    I've never actually attached a mini-connector, Wayne. Have you? Is it a horrible as it looks, or is it just because most people don't, they're always sort-of fumbling through the process, trying to remember the steps?

    Leo
     
  6. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
    Hi Leo,

    Yeah, I’ve done some of those, a long time ago when I was a pro audio installer. We did a some A/V jobs from time to time. If I recall, we used bundled Canare, four conductors (three colors plus sync). As long as you have the right connectors for the cables, and the correct crimping and stripping tools, it’s a piece of cake. Wouldn’t want to try it otherwise, though – at least not crimping.

    Regards,
    Wayne A. Pflughaupt
     
  7. Chuck Paskovics

    Chuck Paskovics Stunt Coordinator

    Joined:
    Feb 26, 2002
    Messages:
    98
    Likes Received:
    0
    Trophy Points:
    0
    Thanks for all the tips guys. I bought the connectors, crimper, and stripper that was recommended for that cable. I tried putting one on to see how it would fit (without crimping it) and it seems to be pretty simple. I do have 3 extras (needed 12, came in packs of 5). I also bought 1 extra foot of wire just in case too.

    I'll try to post some pictures of the parts.
     
  8. Chuck Paskovics

    Chuck Paskovics Stunt Coordinator

    Joined:
    Feb 26, 2002
    Messages:
    98
    Likes Received:
    0
    Trophy Points:
    0
    Ok, for reference, here is the BNC connectors I got:

    http://www.coastcatvsupply.com/Holla...le%20bnc%22%22

    I tried crimping one, but i'll be honest i've never done that and I could not get it to crimp. Where do you crimp it at? At the top, smooth part of the metal or the rippled part? I couldn't get it to budge. Do you need to be arnold swartzenegger to do this??
     
  9. Leo Kerr

    Leo Kerr Screenwriter

    Joined:
    May 10, 1999
    Messages:
    1,698
    Likes Received:
    0
    Trophy Points:
    0
    those BNCs don't look suitable for the thin cable; they look like they're for regular full sized (~.25-.3 inch diameter) cable.

    Leo
     
  10. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
    Chuck,

    I’m with Leo, those connectors aren’t ones you need. Please note at your link that it says they are for RG 59 and RG-6, which is the standard coaxial cable like your cable TV uses.

    As noted previously, your multi cable will need special connectors. The sleeve should have a much smaller diameter compared to the connector body. Look at the smaller secondary sleeve inside the connectors are using – that’s more like what your outer sleeve should look like.

    Whoever you bought your cable from should also carry the correct connectors, or at least be able to recommend an outlet for them.

    Regarding the actual crimping, the crimper’s edge needs to align with the bottom of the sleeve (i.e., the “rippled” part). Assuming you have the correct crimper jaw now, the reason you’re having problems is that the jaw is way too small for the connector you’re using. The connector sleeve should be able to almost drop into the jaw before the crimp.

    Regards,
    Wayne A. Pflughaupt
     
  11. Chuck Paskovics

    Chuck Paskovics Stunt Coordinator

    Joined:
    Feb 26, 2002
    Messages:
    98
    Likes Received:
    0
    Trophy Points:
    0
    Hmmm,

    I followed the link from where I bought the cable that took me to the connectors for that cable and that is what I got...

    http://www.hometech.com/techwire/coax.html#BE-7787A

    The cable seems to fit in the connector just fine, I just can't crimp it.

    Here are some images of what I have...

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
  12. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
    Chuck,

    The cable is not a fit for the connectors you have. The whole cable is not supposed to fit inside the center sleeve of the connector. Only the cable’s center conductor and shield is supposed to fit inside the connector’s center sleeve. The cable’s red outer jacket is supposed to fit over the inner sleeve – i.e., between the inner and outer sleeves.

    This is regular coax, but this is what it should look like finished.


    [​IMG]


    Note that the cable diameter is only slightly smaller than the diameter of crimped section of the connector.

    This website shows how to crimp coaxial cables. It’s RG-6 and –59, but the concept is the same.

    http://www.interstateelectronics.com.../coaxterm.html

    Regarding the crimper, I can’t tell if it’s the right one, because it’s too dark to see the jaws. But, if it’s the correct crimper for the connectors you have, you’re going to need a new crimper when you get the right connectors.

    The Hometech link you provided us has a link to the proper connectors (note how small the sleeve is compared to the connector). It also has a link to a “correct” stripper and crimper, but since it doesn’t specifically say it’s for the miniature coaxial cable, I’m not confident they are the correct tools.

    Regards,
    Wayne A. Pflughaupt
     
  13. Chuck Paskovics

    Chuck Paskovics Stunt Coordinator

    Joined:
    Feb 26, 2002
    Messages:
    98
    Likes Received:
    0
    Trophy Points:
    0
    Well, I ordered the connectors that they recommended (the ones in the link) as well as the stripper/crimper in that same link.

    When stripped down, the white part fits perfectly inside that center tube, while the rest slides on the outside of the center tube, as you see in the picture. Then when pushed in the center tube pushed up under the red plastic.

    I was able to crimp the connector, but when I pulled hard enough the cable did come out.
     
  14. Chuck Paskovics

    Chuck Paskovics Stunt Coordinator

    Joined:
    Feb 26, 2002
    Messages:
    98
    Likes Received:
    0
    Trophy Points:
    0
    Here is a close-up of the crimp insert...

    [​IMG]
     
  15. Chuck Paskovics

    Chuck Paskovics Stunt Coordinator

    Joined:
    Feb 26, 2002
    Messages:
    98
    Likes Received:
    0
    Trophy Points:
    0
    Also of note, the link to the pdf page of the connector specs I believe is not the exact same ones that I have. I just realized the part numbers do not match the ones I ordered. They look similar, but mine are made for the 1855a (.16) mini cables.
     
  16. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
    So, you’re in business now? By the way, I gave you some bad information before. Only the white dielectric goes inside the sleeve. The shield goes outside.

    Regards,
    Wayne A. Pflughaupt
     
  17. Chuck Paskovics

    Chuck Paskovics Stunt Coordinator

    Joined:
    Feb 26, 2002
    Messages:
    98
    Likes Received:
    0
    Trophy Points:
    0

    Yeah, I guess it works ok. I was a little concerned that I was able to pull the wire out, but it didn't come out without a little force. These will be going in the wall, so once they are in place they will never be moving. I guess we'll see when I hook all this stuff up!
     
  18. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
    Yes, it should take some effort to pull it off. Sounds like you’re okay then!

    Regards,
    Wayne
     
  19. Chuck Paskovics

    Chuck Paskovics Stunt Coordinator

    Joined:
    Feb 26, 2002
    Messages:
    98
    Likes Received:
    0
    Trophy Points:
    0
    Thanks for all the help/advice/troubleshooting! I think I am ready to go.... Now I just have to wait until they finish my house!
     
  20. Leo Kerr

    Leo Kerr Screenwriter

    Joined:
    May 10, 1999
    Messages:
    1,698
    Likes Received:
    0
    Trophy Points:
    0
    Crimping is always a little strange until you get the hang of it.

    You did, at least, have one advantage going for you - the individual cables were color-coded. The last component hook-up I did was with 3 Beldin RG-59 off of the same reel - three black cables. Fortunately, they were only about 6' long, so I was able to track which was which fairly easily...

    Leo
     

Share This Page