Hi, i want to buy some of these plugs but can't find out what they are called.
Thanks, Gary.
For anyone else that didn't know, they are called Dupont crimp connectors.
And they are painful to crimp.
are they servo connectors?
gcjr:
are they servo connectors?
General purpose connectors, they are really quite useful. I use them often for low current applications, for power or signal, generally anything around 500mA and <12v. Very useful for quickly connecting/disconnecting modules to MCUs in my project boxes, makes troubleshooting and removal of modules much easier in boxes with tight spaces, when soldering the wires itself is not crucial.
I've got a crimp for it, but it doesn't work well at all, probably because it is a crap crimper. I get better results just using needle nose pliers.
You may be able to avoid the crimping problem with those multi-way DuPont connectors by simply using commonly available ready made single DuPont connectors, removing the housing, and inserting these in the multi-way housing. I use this trick from time to time and bought a small selection pack of the multi-way housings.
Paul__B:
And they are painful to crimp.
Not if you have the proper tool.
commonground:
Hi, i want to buy some of these plugs but can't find out what they are called.
Thanks, Gary.
Paul__B:
And they are painful to crimp.
Actually they are simple to make up, see this PDF:
https://forum.arduino.cc/index.php?action=dlattach;topic=376971.0;attach=153794
The "pain" is in getting the correct tool! 
Paul__B:
The "pain" is in getting the correct tool!
Take some wire lengths and some terminal ends to you favourite electronic tool store.
Before buying, try ‘their’ crimpers out to find the best tool that works for you. 
I like the yellow handle version in the PDF I posted above.
commonground:
Hi, i want to buy some of these plugs but can't find out what they are called.
.Thanks, Gary.
I believe your "plug" is actually a socket
I have the correct crimp tool, and my success rate crimping is still miserable.
If you search for Dupont jumper DIY on ebay you can get that ribbon cable with pre-crimped ends without the 1p housing, and put your own Dupont housing onto it to make up custom cables, for a fraction of what pololu charges for such wires - the downside though is that you dont get to pick the colors. A while back I spent like $200 on pololu jumpers like that because I needed them all to be white because they were going against the wall, and crimping them myself, or spraypainting the ribbon cable white (takes like 5+ coats to keep the color from bleeding theough) took more time than I had.
And they are painful to crimp.
Up until a few days ago I would have agreed with you. However I purchased this crimper and was able to make great crimps. I also made some crimps on a JST 3.96 mm connectors and they came out good as well.
now you all got me worried! This kit just arrived today. Unfortunately I haven't had a chance to play with it yet. Fingers crossed
Hutkikz:
now you all got me worried! This kit just arrived today. Unfortunately I haven't had a chance to play with it yet. Fingers crossed
This looks okay, tell us how you like it.
Review the PDF in post #8 above.
larryd:
This looks okay, tell us how you like it.
Thanks for the affirmation. I didn't get to do my usual research as a co-worker offered to buy this so that I could upgrade his 3d printer to a 32bit board. I'll let ya know how it goes.
Review the PDF in post #8 above.
Love your thread Larry. And digging back through it for this was on the agenda until I saw your link here 
commonground:
Hi, i want to buy some of these plugs but can't find out what they are called.
Thanks, Gary.
These are not "plugs", these are female DuPont sockets which you can buy off ebay and spend painful hours crimping....
Quintus26:
These are not "plugs", these are female DuPont sockets which you can buy off ebay and spend painful hours crimping....
(Darth Vader voice): I find your lack of skill disturbing...
I found by squeezing the insulation tabs on the terminal slightly, the terminal will be held to the wire by these tabs, allowing you to put the terminal into the crimper more easily.
If you put the terminal in the crimper first, you are inserting the wire blind and may not obtain the correct placement.