BNC Crimping - Page 1
Forum section: electronics / beginners

author: Stonent
author_rank: Super Contributor
timestamp: October 11, 2013, 12:29:06 am
content: I am adding a BNC end to my Geiger counter cable and have bought some that look like this:http://www.computercablestore.com/images/products/No%20Manufacturer/1-B58TNETMCC.jpgThe little gold pin also has a tiny hole in the side. The cable I have is just a little thinner than RG58 cable and has a stranded core rather than solid, so I twisted the core and lightly tinned it and was wondering if I should try to solder it in to the center pin? I think I could just heat the pin and the tinned wire inside might bond to it.I'm just slightly concerned that the stranded core may not hold up as well and move around inside the pin and have intermittent glitches. What do you think?

author: Monkeh
author_rank: Super Contributor
timestamp: October 11, 2013, 12:35:18 am
content: If it's designed for crimping, crimp it. Stranded will be fine. Strip further back and cut off the tinned bit, or you will get a bad joint.

author: Stonent
author_rank: Super Contributor
timestamp: October 11, 2013, 01:09:17 am
content: So should I crimp the center pin as well?

author: Monkeh
author_rank: Super Contributor
timestamp: October 11, 2013, 01:15:46 am
content: If the pin you've got is for crimping.. crimp it.

author: nanofrog
author_rank: Super Contributor
timestamp: October 11, 2013, 01:25:24 am
content: Quote from: Stonent on October 11, 2013, 01:09:17 amNo. Don't crimp + solder as a general rule (unless the terminal calls for this explicitly).Just use the connection means the connector is designed for (crimp a crimp terminal, solder a solder terminal).

author: Jeff1946
author_rank: Regular Contributor
timestamp: October 11, 2013, 02:41:41 am
content: Does the center pin have a small hole in side of the part the wire goes? This is to aid soldering. I would put wire in pin, heat and put solder into the hole. Crimping the outer part correctly required the right kind of tool. You can probably get away an ordinary crimp if the cable won't be flexing too much.

author: Rufus
author_rank: Super Contributor
timestamp: October 11, 2013, 03:20:16 am
content: The pin in the linked photo looks too solid for crimping. The hole is to vent gas when soldering. Try to get the solder to wick down the wire. Tinning the wire first won't hurt if it still goes in the hole. If you get a bit on the outside of the body it is probably easiest to scrap it off with a sharp blade.The barrel is definitely meant to be crimped over the screen. Pretty much impossible without the right tool which has jaws with a hexagonal hole of the right size.

author: SeanB
author_rank: Super Contributor
timestamp: October 11, 2013, 04:44:25 am
content: Centre on those is soldered, and the outer is crimped. Did you get the sleeves as well for them? I have done hundreds over the years, and still have the tooling. Small amount of solder on the tinned inner is all that is needed, until you can see the solder wet the hole as you feed in from the rear with the iron on there as well. Some can be crimped, but the soldering is more reliable.

author: Stonent
author_rank: Super Contributor
timestamp: October 11, 2013, 05:41:09 am
content: Quote from: SeanB on October 11, 2013, 04:44:25 amYeah the plug, golden bullet, and the sleeve.I didn't think about it until right now, but it probably would have been easier and cheaper for me to buy a 10ft (3m) rg58 network cable and cut it in half and pull out the old 50 year old wire from the probes that I have and solder that in. Oh well live and learn.

author: G7PSK
author_rank: Super Contributor
timestamp: October 11, 2013, 10:53:25 am
content: I have a load of similar looking BNC plugs. the pin has a hole on one side but I have always crimped the pin with the small hex crimp on my crimping tool the crimped the sleeve as well.Heres a video on how to do it.

author: Monkeh
author_rank: Super Contributor
timestamp: October 11, 2013, 02:17:56 pm
content: Quote from: SeanB on October 11, 2013, 04:44:25 amProperly crimped connectors are more reliable than soldered where the cable is flexed.

author: Neilm
author_rank: Super Contributor
timestamp: October 11, 2013, 03:07:40 pm
content: Quote from: Monkeh on October 11, 2013, 02:17:56 pmThere are some industries where you explicitly are not allowed to use solder to terminate a wire. Others let you, but generally the standards require that the wire be additionally supported.

author: ConKbot
author_rank: Super Contributor
timestamp: October 12, 2013, 03:38:58 am
content: Quote from: Stonent on October 11, 2013, 12:29:06 amA lot of crimp pins have a hole in the side, its an inspection window so either the operator, or the inspector can verify that the wire was inserted fully when the wire was crimped. A hole in the side doesnt mean its meant for soldering.If you can make a pin fit on a wire, generally you can solder it, and it will be fine for most uses. However in order for a crimp to be more reliable than soldering, it must be the correct size wire for the pin and the correct tool Get either of those wrong and soldering (properly) will be better.And for a BNC, given the design of 99% of BNC connectors (or at least the ones ive seen) no way youre going to fatigue the center conductor to fail before the shield braid breaks. 95% of BNC failures IVe seen were the braid fatiguing and breaking at the entrance to the crimp ferrule. (put on a boot or at least some adhesive heatshrink if youre going to be handling it a lot, i.e. test bench use) The other 5% were pins crimped onto the solid core of RG-58-ish coax getting lose and making for a real bastard intermittent connection to find.That being said, IVe been crimping center pins onto real RG-58 before and had the pins shatter because they were hard/brittle and meant for soldering not crimping.

author: sub
author_rank: Regular Contributor
timestamp: October 12, 2013, 10:30:35 am
content: The instructions that I was given when I learnt to do this were as follows:Put ferrule and heatshrink over the cable. You only get to forget to do this once per cable.Strip the insulation/dielectric, trim and spread the braid, etc.Solder the centre pin and check continuity. You don't need much solder, it shouldn't be bulging out the side.Slide the body over until it clicks into place, put the braid back into place over the body, then slide the ferrule over and crimp.Check continuity again. Do thisnow, since if you wait until both ends are done you won't know which needs to be cut off if there's a problem.Heat the heatshrink.Right-angle connectors are a bit trickier (for SMA at least) because there is no separate centre pin---you have to solder the centre pin through the 5ish mm hole in the back.

author: Rufus
author_rank: Super Contributor
timestamp: October 12, 2013, 07:45:55 pm
content: Quote from: G7PSK on October 11, 2013, 10:53:25 amAfter seeing that video I will buy the pin is intended to be crimped. The shoulder on the end didn't look right to me but I see the crimp tool is supposed to miss it.

author: geraldjhg
author_rank: Regular Contributor
timestamp: October 14, 2013, 12:32:46 pm
content: hiyes carefull soldering is better than doubtfull crimpingand you try and try till it looks perfect, might helpto have a teflon cblesaludos