Connection torque of D38999 circular connectors?

[Afazz]

Long time lurker, but apparently this is my first post! I'm a mechanical guy so I apologize in advance for any stupid questions

I'm wiring a show car (hobby, not professionally). I just received a bunch of MIL-DTL-38999 Series III connectors I purchased. I've used the bayonet style connectors, but this is my first time using the threaded Series III connectors. It seems when the EMI grounding fingers engage it gets much much harder to turn while mating. Is this normal? I know that's a bit vague... I don't know how/who else to ask.

The manufacturer of these connectors is Deutsch. Is it a quality issue? They were about half the cost of equivalent ITT Cannon or Amphenol.


Here is a picture of the connectors:

http://i455.photobucket.com/albums/qq280/afazz65/bay/100_1688.jpg

 

[IRstuff]

Not sure what you are referring to. The connectors have no EMI "fingers." The protrusions on the sides are indexing keys, so that you don't misconnect connectors. Are you doing this without the connector pin inserts If so, they should mate pretty easily, since the connection torque is usually dictated by the connector pin insertion force.

The connectors are mated when red band on the side of the bulkhead connector is covered by the mating connector.

TTFN

FAQ731-376

 

[MacGyverS2000]

To add to that... unless the connector has a hex form on the outside edge, they're meant to be installed by hand. If you can't crank it down by hand, something is not mating up.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Afazz]

The "fingers" I'm referring to are shown here, they are hidden underneath the mating nut and make contact with the receptical:

http://www.ttiinc.com/props/IO/12542/204/amphenol_amphe_lite.jpg

I am connecting without pins or sockets, but you can feel the shell threads tighten up far before it gets close to the red band. Both connectors have the same keyway rotation (Normal) and both are electroless nickel plated.

It might just be that you can't learn "feel" from a catalog and I'm being paranoid, I will try again this evening. Thanks for your replies!

 

[ScottyUK]

Yes, it will tighten up when the EMI fingers engage. If the connector is unloaded then the difference will be quite pronounced. Once it is full of contacts the difference will be less apparent, although you will still feel the change.


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If we learn from our mistakes I'm getting a great education!

 

[IRstuff]

Yes, there should be a change as you get to the last 0.1" before the red band. That is as it should be; it's been a while since I've turned that type of connector, but everything sounds the way it should be.

TTFN

FAQ731-376