I'm trying to identify a connector on a stepper motor so I can purchase a replacement for the missing female connector. Just to be clear, I'm not asking where to buy the part (since I can probably find it once I identify it, but I wouldn't throw away a link if given one), I just need to figure out what kind of connector it is, at the moment. (I wouldn't mind a wiring diagram, but I'm sure I can figure that out by looking at how the other motor connectors are wired and by applying a multimeter to the motor itself.)

The motor is off a Light Machines Corporation SpectraLight small vertical mill. It's probably 20+ years old. These mini-machines were often used in classrooms, which is where this one was used. I got it cheap and am doing some basic repairs and moderate upgrades.

The User's Manual isn't any help. Here's an eBay listing for a similar machine/model, if it helps you.

I can find information about 4, 5, 6, and 8 pin stepper motors, but not 7 pin steppers.

7 pin connector

This is a different angle of the same motor, just the protective sticker is still on the back of it.

7 pin connector top

This looks like a fairly standard NEMA 23 sized motor. I could just replace the motor, but I don't want to spend much more money on the machine right now, and I'd rather use the presumably working motor I already have. Most of my repairs and even upgrades are with parts I already own.

Motor side

Here's a pic of the only identifying marks/numbers on the motor. I've removed another motor and the handwritten number is 16 and instead of T3995 26, it says T3995 24. The whole body is the same textured black enamel paint you see in the other pics.

Only identifying numbers

I've searched for T3995 stepper motors, but evidently that's a fairly common designation with AC and DC motors as well as stepper motors. There's just too many options to sort through without some more specific search term.

I'm posting here because other Stacks don't seem to allow parts identifying questions, and a CNC machine is technically a robot. Plus I figure people who could recognize a stepper motor by sight would be here.

The dimensions of the connector are 9.2mm deep, 24.4mm wide, 8.5mm tall, and the sidewall is 1.8mm thick, with the pins at a standard 2.54 mm spacing. There are labels A-H for the pins on the plastic. One long edge of the plastic has 2 perpendicular slits in it to presumably act as a key and a catch.

Here are some close ups.

Close up top Close up side Close up side 2

Here are some pics of the connectors I have.

Connector close up Connector side Connector markings

In case you are unable to make out the markings, it says "Pull Here" and "1-87175-7".

  • $\begingroup$ @jsotola, people wonder why newcomers feel unwelcome. Well, your comment is a perfect example. Instead of making comments about how I'm failing to meet your needs, just leave off that first sentence and just start with the "Please add a clear..." It makes for less of a judgmental comment. BTW, I've added more pics, including that of one of the connectors I have. It turns out this isn't an off-the-shelf connector, like I thought it would be, but rather a standard 8-pin connector and some sort of boot possibly heat-shrunk around it. $\endgroup$ Mar 16, 2022 at 15:55
  • $\begingroup$ @jsotola, thank you for explaining that to me. I'm not perfect at being non-judgmental, either and something I work on, too. I think mentioning the problems, without saying how badly I've done, after asking for better and more pics would have been better. If your first statement would have been last and stopped after the 2nd comma, it would have been fine, IMO. $\endgroup$ Mar 16, 2022 at 17:18
  • $\begingroup$ thanks for feedback $\endgroup$
    – jsotola
    Mar 16, 2022 at 19:44

1 Answer 1


As it turns out, this isn't what I would call an "off the shelf" part, but rather a hodgepodge of 2 off-the-shelf parts.

With the number "1-87175-7", I was able to find the standard 8 pin connector, sans pin plug, that's currently used on my machine. There's also a boot around the plug, making it look more like a custom-built plug.

Example: https://www.digikey.com/en/products/detail/te-connectivity-amp-connectors/1-87175-7/291456

The 2 slits perpendicular to each other on one side made me think there was a keyed clip on the connector to make sure it didn't fall off and was always attached the correct direction. Maybe there still is a connector like this around, but I can use a 2.54mm 8 pin connector for now.


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