Can I add a slot to reach a thread hole?

[SethH]

I am designing a panel with an M8 x 1.25 threaded hole through the panel. I want to add a slot, 0.180" wide, that reaches from the edge of the panel to the threaded hole. I have a strain relief fitting that I would like to thread into the hole. But this fixture will be subject to vibrations.

Will removing approximately 1/4 the material the fitting screws into be too much to be sure of a secure fit?

Thanks for your help!

 

[MikeHalloran]

I assume the slot is for radial assembly of the wire going through the strain relief, preassembled at some other stage.

Unfortunately, the slot will tend to chew up the strain relief as it's screwed into the panel, and even if that's not a problem, the strain relief may ooze into the slot after installation, and thereby fail to do its job.

The slot will also be fairly expensive to add. A punched slot would interfere with the tapping operation, so it has to be milled after tapping. ... unless a bandsawed slot would be acceptable; most shops would refuse to do it that way absent specific instruction.

IOW, absent considerable justification (a lot more than 'I want') in its favor, the slot is a terrible idea.



Mike Halloran
Pembroke Pines, FL, USA

 

[SethH]

Thanks Mike for your help. You're right, the slot is for radial assembly of the wires passing through the strain relief fitting. The fitting itself though is made of nickel plated brass, with material inside that is compressed around the wires as a nut is tightened. Given this, do you still think there could be issues with assembling the fitting to the panel? Thanks!

 

[MikeHalloran]

The only remaining issue is twisting the wire bundle to screw the strain relief into the bulkhead, which doesn't do the wires any good.

... for which purpose you could pre-twist the wires, but half the time that will be done in the wrong direction, making matters worse.

... and you're probably paying way too much for strain reliefs, and for slots.



Mike Halloran
Pembroke Pines, FL, USA