why are jackscrews so hard to figure out?

[dbur]

We constantly struggle finding the right jack screws.  It's been this way for years.  Why?

I'm using a 189588 cable and the big end 68 pin connector data sheet does not specify the thread size.  The connector wants an M2.5 stud jackscrew.  The screw on the cable is definitely not M2.5.  Maybe 2-56?

How in the heck do you find jack screws that work?  The only one I found from Harding is obsolete.  I have one set in my hands that is right, but no idea how to specify it or get more.  The connector accessory kits from NI have no real description of what they are or what they contain.

Can someone at NI help?

[santo_13]

Check out the screws offered by Molex - https://www.mouser.com/catalog/english/101/apac/1210.pdf

[dbur]

Those are for the VHDCI connectors.  I need one for the larger MIO connector.  Looks like M2.5 post and 2-56 socket. 😞

Actually I think the socket is not quite a 2-56, so I don't know what it is.

[santo_13]

Looks like it is a TE part, search the TE website for the exact screw

https://www.te.com/usa-en/product-5787394-7.html

[dbur]

OK, seems there is only one solution.  NI part 187949-01 (4 pcs).  If only NI gave the thread sizes in the cable data sheet and also in the description of this PN then it would have been a lot easier.  Turns out it is an M2.5x2-56 thread set.  Guess how much these cost?  One jackscrew is about $9-$14.50 depending on where you buy it.

[santo_13]

Probably some custom made ones.

https://www.ni.com/en/support/documentation/supplemental/15/ni-daq-device-custom-cables--replacement...

[dbur]

If they would just detail what is in those kits and the spec for the cable I could have figured it out.  As it is I had to buy one to know if it was going to work or not.  😞

[KBerger]

Going thru the same issue now. Trying to get NI support to state sizes officially or provide engineering drawing. Definitely want M2.5 male with 2-56 female.

[KBerger]

So M2.5 male threads stud, 2-56 Female threads socket

Response from NI Support   

---------- Forwarded message ---------
From: NI Technical Support <technical.support@ni.com>
Date: Mon, Jun 1, 2026 at 12:42 PM
Subject: [Request #: 04455991] Jack Screw 187949-01 [ ref:!00Di00jTAB.!500VU0yLCeo:ref ]

Hello,

My apologies for missing this information, as you stated the socket thread size is 2-56.

Best regards,

Daniel Soto
NI Support | Post-Sales Services Delivery
ni.com/support | 866-275-6964

Sent: 6/1/2026, 10:48 AM
To: technical.support@ni.com
Subject: [EXTERNAL] Re: [Request #: 04455991] Jack Screw 187949-01 [ ref:!00Di00jTAB.!500VU0yLCeo:ref ]

Hello Daniel,
The screw part is M2.5, but what is the socket thread size? 2-56 or M# ?
Thanks.

On Mon, Jun 1, 2026 at 11:40 AM NI Technical Support <technical.support@ni.com> wrote:
Hello,

I hope this email finds you well, this is Daniel from NI.

Thank you for reaching NI technical support, I want to let you know we have received your email and I will be assisting you with your query. Regarding what you sent us earlier in the email, I understand that you are currently looking for the thread count on the (1) 4 Piece Jacksocket Kit for Connecting Screw Latching Cables

This is a 68-Position SCSI-II Jacksocket, M2.5 Screw, .348" Length, .148" Head Length. Please let me know if there is any other question or concern, and I will be more than glad to assist! You can contact me by replying to this email or calling me at 866-ASK-MYNI (866-275-6964) with your Support Case number.

Kind regards,

Daniel Soto
NI Support | Post-Sales Services Delivery
ni.com/support | 866-275-6964