Less aggressive male headers

John Kauffman

I have a custom PCB with male header pins on bottom aligned to go into the 35 holes of the three female socket strips of a Parallax board: ActivityBoard / PropBOE / BOE / Homework. I have to take the PCB on and off frequently. The connection is not under mechanical duress like pressure or vibration; I just need an electrical connection and enough mechanical friction for the PCB to not fall off if simply turned over.

Although I hate the word "Standard" that is what I have used for the male header. The problem is that they are so tight into the Parallax board female headers that it is very difficult to remove the PCB board. I have looked at Digikey for a male header that uses slightly smaller pins but am overwhelmed by the choices.

Does anyone know the description, Digikey part number or other source for strips of male headers that use slightly smaller pins?

Thanks.

Phil Pilgrim (PhiPi)

Overly aggressive male headers are almost always a symptom of testosterone poisoning or, in very rare cases, an extra Y chromosome. Unfortunately, aside from counseling and anger management classes -- which are almost never effective -- there's very little that can be done about ithe problem, and your headers will sooner or later end up in the justice system.

In all seriousness, the tightness is a function of the .025" square pin size, which is standard, and not the length. I don't think you will find headers that use a different pin size and still have the 0.1" standard spacing. There are low-insertion-force connectors, but those are always sockets, not pins, since that's where the spring-loaded connection points reside. If you have room, you might consider adding PEM (clinch) nuts to the bottom of your board near the connectors. Then you can use screws against the Activity Board to gently lift your board out of the sockets.

-Phil

John Kauffman

I did select terminology shaded with double entendre and am surprised only one remark came back.

Thanks for benefit of your experience on pin options. I've also thought about attaching a crude strap to the middle of the board to pull it up.

This is part of my years-long quest to get a prototyping PCB shield to fit over the breadboard of Parallax boards. Then I can solder on 40 of those boards each of the activities from WAM and be able to swap them out quickly for class demos.

Domanik

Hi John,
A few years ago I used 18mil round pins in a project. They have slightly less insertion force than the 25mil sq pins but still make decent electrical connection. The cost is higher and I spent a lot of time looking for something with the right specs and that was inexpensive.

It might be possible to use ejector tabs instead of going to different pins.

Good Luck,
Dom..

Publison

I agree with the round pin approach. Search for "Machine Pins". There are elusive, and most are not long enough to seat correctly.

John Kauffman

Thanks, looks like several models of those are available.

Domanik

John,
Something that might also work is an ejector lever you can make from scrap PCB or plastic or even wood. It would have a 1/4" nylon standoff attached with a 4-40 or so screw. The body would be 3" by 1.5". It would be rounded into semi circles on both ends. At one end the standoff would be mounted near the edge at 45 degrees. To operate: one end of the body would rest on the main board and the standoff would slip under the daughter board; the lever would then be rotated to apply force near the middle of the connector to the underside of the daughter board. That should pop it right off.

Sorry for the thousand word description but I can't seem to upload a jpeg for some reason. How about I just put it in my avatar--sheesh!

Get luck, Dom..

John Kauffman

Thanks. I got it from the description and sketch. Regardless of the pins, having a tool to apply the right pressure ot the right location will extend the life of the boards.