Which end of these do I solder? - Page 1
Forum section: electronics / beginners

author: knotlogic
author_rank: Regular Contributor
timestamp: November 08, 2019, 02:23:55 am
content: This is probably a very dumb question, but which end of these turned pin headers is meant to be soldered into my PCB and which end is for plugging into other parts?I picked up a bunch of these cheap for proto boards that get plugged into breadboards. I was finding that regular square pins were a pain to plug in/pull out of the breadboards I have and was worried about breaking something.

author: gamalot
author_rank: Super Contributor
timestamp: November 08, 2019, 02:30:30 am
content: I don't know what's the name of it in English, may be the end look like "stepped shaft"?

author: knotlogic
author_rank: Regular Contributor
timestamp: November 08, 2019, 02:49:21 am
content: Quote from: gamalot on November 08, 2019, 02:30:30 amHonestly, as a native English speaker, I'm not sure how to describe it either! The bit on the right?

author: SL4P
author_rank: Super Contributor
timestamp: November 08, 2019, 03:19:21 am
content: They’re interesting headers...They look like they’re probably intended for wire wrap on the shorter ‘rough’ end.That’s the side I’d solder on, and leave the smooth ‘round’ pin for the breadboard.

author: MarkF
author_rank: Super Contributor
timestamp: November 08, 2019, 04:36:44 am
content: Quote from: SL4P on November 08, 2019, 03:19:21 amNot wire-wrap posts. All wire-wrap posts are square so the corners dig into the wire.The side with the larger diameter is for soldering.The side with the smaller diameter is meant to plug into an IC socket.Here is an example USB Adapter board from DLP Design:

author: Brumby
author_rank: Unknown
timestamp: November 08, 2019, 04:43:30 am
content: Quote from: MarkF on November 08, 2019, 04:36:44 amJust so. Square posts are the secret to the success of wire-wrap!!

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: November 08, 2019, 04:51:35 am
content: The conical end stands above the board. The cylindrical one is closer to the solder joint. As I see on the picture posted, the right side is where the solder connection is made.

author: magic
author_rank: Super Contributor
timestamp: November 08, 2019, 07:38:37 am
content: I have seen them called Single  In-Line connectors, SIL in short.As others said, the thick side is soldered, the thin side goes into a SIL socket. They can also be plugged into breadboards or DIP sockets.

author: tooki
author_rank: Super Contributor
timestamp: November 08, 2019, 12:01:33 pm
content: Quote from: knotlogic on November 08, 2019, 02:23:55 amNot a dumb question at all.As others said, the thicker side goes in the board, the thin conical side are the pins.Your worry about square pins (or the thick side of these male headers) damaging things is valid: while I've found that breadboards seem to handle it OK (at least if they're of decent quality), if you insert the thick side into a female turned socket, you will permanently damage the socket. I learned this the hard way when fiddling with them. (Luckily, before soldering the sockets into anything!!)

author: tooki
author_rank: Super Contributor
timestamp: November 08, 2019, 12:05:21 pm
content: Quote from: magic on November 08, 2019, 07:38:37 amI think they weren't talking about what the whole device is called, but rather what to call the shape on the board-side half of it!(As for what the whole thing is called, I'd call these "machined headers", by the way, in this case, a male one.)Quote from: knotlogic on November 08, 2019, 02:49:21 amI'd say maybe the side with the flat shoulder.

author: knotlogic
author_rank: Regular Contributor
timestamp: November 10, 2019, 10:42:29 am
content: Thanks all!Quote from: tooki on November 08, 2019, 12:01:33 pmIt's not just the damage to the breadboard putting square pins in, I've had plenty of problems pulling themoutas well. I had a protoboard that was essentially a 40 pin DIP which I've had to lever out very carefully. (Plugging it in also came with risk of damage to my fingers.) Built up another with the turned pin SIL connectors and it was a lot easier to plug in/out.

author: ggchab
author_rank: Frequent Contributor
timestamp: November 10, 2019, 04:53:21 pm
content: I think they are supposed to be used with female tulip pin headers. Try one and see which side fits best and solder the other one

author: Kirill V.
author_rank: Regular Contributor
timestamp: November 10, 2019, 06:41:34 pm
content: Oh, someone mentioned the method of wiring invented by IBM for their mainframes. I very much doubt that in the 21st century someone will produce accessories for this. And these connectors have nothing to do with such a method.The side that has flat pads on the contacts should be adjacent to the board. A flat PCB goes perfectly with flat pads of contacts, in my opinion:)

author: kjr18
author_rank: Regular Contributor
timestamp: November 10, 2019, 09:25:53 pm
content: So flat side to the board. But what if I want to use them with female machined pin headers? Those longer pins are too loose in mine, and these shorter ones are much better fit for those.

author: magic
author_rank: Super Contributor
timestamp: November 11, 2019, 12:08:59 am
content: If you stick the thick end into a female socket then only the thick end will ever work in this socketIt's not how they are supposed to be used, but you can.Another abomination I have seen: transmale connectorsSlide a cable into a female socket, solder it in, stick the mounting pins like a male plug into a female socket.

author: tooki
author_rank: Super Contributor
timestamp: November 11, 2019, 01:38:30 am
content: Quote from: ggchab on November 10, 2019, 04:53:21 pmTulip pin?? Is that autocorrect of “turned pin”? (Which we all already knew.)But as magic just said, and I said a few days ago: if you stick the thick side of these male headers into a female turned socket, you WILL permanently damage the socket, and the socket will never again accept the thin (correct) side, nor actual ICs, correctly.Quote from: Kirill V. on November 10, 2019, 06:41:34 pmAre you talking about wire wrap? That wasn’t invented by IBM. It’s certainly quite rare today, but many parts are still made. Look at the full Mill-Max catalog, you’ll be surprised at how much wire wrap stuff they still make. And you can still get wire wrap tools.

author: tooki
author_rank: Super Contributor
timestamp: November 11, 2019, 01:42:53 am
content: Quote from: kjr18 on November 10, 2019, 09:25:53 pmDid you insert the thick side of the male header into the female turned header, even just once? If so, the female header is ruined and must be replaced.

author: Kirill V.
author_rank: Regular Contributor
timestamp: November 11, 2019, 03:55:53 pm
content: QuoteYes, I talked about it. As far as I know, IBM used it. For some reason I thought they invented it.Wire wrapping was used in the USSR and books were written about it. I read these books.

author: tooki
author_rank: Super Contributor
timestamp: November 12, 2019, 10:57:23 pm
content: Quote from: Kirill V. on November 11, 2019, 03:55:53 pmIBM definitely used it, but it was invented many years earlier. Wiki says Bell invented it.

author: DBecker
author_rank: Frequent Contributor
timestamp: November 14, 2019, 07:11:02 pm
content: Wire wrapping was used in telephone central offices long before it was used for the general purpose electronics.I used wire wrapping in the early 1980s. By then it was mature, with a body of knowledge from decades of experience. There was a large, detailed set of rules to make reliable connections. The pin and wire plating, wire gauge, insulation type and thickness, etc were precisely specified and standardized. If you followed the specified techniques, the result would be very reliable. Not quick, not easy, not easy to debug, not inexpensive, but very reliable.For my hobby projects I had one of the inexpensive double-ended hand wrap tools. One end was for unwrapping, the other for wrapping, with a wire stripping groove in the middle. I think that most hobbyists of the era had that tool and a spool of the blue insulated silver-plated 30 AWG wire. A hobby alternative was a soft insulation wire intended to be used without stripping, with the square post cutting through the insulation, but that wasn't considered as reliable.The setup I used for large boards was typical for commercial prototyping. There was wire storage, and the X-Y assembly machine. Wire storage was a panel with storage tubes for pre-cut, pre-stripped wires. Each tube held a different length, and the pre-cut wires had insulation color coded for their length. (Hmmm, DigiKey still sells the wire packs. $9.50 for 50 pieces of the shortest length, which is about what it cost "back in the day". For a typical 2000 wire board that's $400 for just the wire!) The assembly frame had two stepper motors that moved an L-shaped bracket. A tap on a foot pedal moved the bracket to the origin location and flashed the wire length on a LED display. A line-powered wrap tool ($$$) was used to spin the wire down. A second tap moved the bracket to the destination, which was always lower and/or left. That allowed for "Manhattan routing" (e.g. always horizontal then vertical) of the wire while the guide was slewing to the new location, and reduced the chance of damage from tapping the pedal a little early.