Penetrator hole sizing for Subconn Connectors


We are in the process of designing a hole layout for a blank end cap such that we can include Subconn connectors (specifically, the DBH8F/M and BHB2F/M). We wanted to ask what the recommended hole size for these two bulkheads might be, as we don’t have much experience in mechanical design.

Would it be recommended to use nuts with O-rings in order to fasten the penetrators onto the end cap or thread the holes? Any help and recommendations would be greatly helpful!

Additionally, for actually drilling the holes to the positions that we draw them to, how would you recommend we take references? Our drawings are relative to the center of the blank end cap, what would be the easiest way to identify this “center” of the end cap?

Thank you!

7/16" is the size drill bit you need for a clearence hole. A 7/16-20 UNF tap is what you would use on a hole drilled to 25/64 hole (tough bit to find!) is the standard tap drill size for that thread.

You can thread the holes to use a minimum of space, but make sure to use thread locker sparingly to not affect the face-seal o-ring performance! (on the underside of connector bolt.)

To identify the exact center may be tricky. You could use calipers to draw two lines - each with endpoints found at the maximum measured size. Where they cross would be the center, or at least very close to it. You could also print a 1:1 template from a cad program (freecad or autodesk fusion?) and use that to mark your hole centers - don’t forget to put the center-mark on the drawing! A punch like this is a must for center marking the holes, and ensuring that the drill bit starts where you want it too. They work great, especially in metal as soft as aluminum!
For both drilling and tapping, it may pay to use a drill press, cnc, or diy jig to keep the holes as straight relative to the material as possible…
Hope that helps!

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