Self clinching studs........
Discussion
Hoping someone might know the answer to this, it's an electronics question, but the actual detail is sheet metalwork, so I'm hoping someone will know.
I'm looking to use some "press in" self clinching studs, probably about M3 to hold a transistor onto an aluminium box.
Obviously the head is serrated, to stop it falling out, when there's no nut to hold it in, but whenever I've seen these things used you would be hard pressed to move them with your fingers, even when there is no nut on them.
I guess that there's an issue with limits and fits, but because of the serrations, I'm really not sure what sort of seat is best for these things. Do you just drill a hole that's slightly undersize? Or do you counterbore, or maybe countersink?
In anticipation.
I'm looking to use some "press in" self clinching studs, probably about M3 to hold a transistor onto an aluminium box.
Obviously the head is serrated, to stop it falling out, when there's no nut to hold it in, but whenever I've seen these things used you would be hard pressed to move them with your fingers, even when there is no nut on them.
I guess that there's an issue with limits and fits, but because of the serrations, I'm really not sure what sort of seat is best for these things. Do you just drill a hole that's slightly undersize? Or do you counterbore, or maybe countersink?
In anticipation.
GreenV8S said:
I guess the tighter fit the better so I'd just go for a tight interference and not bother about the shape too much. Have you considered using rivnuts instead of just press-in fittings?
I'm sure that rivnuts are a more secure fitting, but I'm using a transistor that only has one mounting hole, so I don't really need the floating type, it could just use a tapped hole.
On the other hand the box is to be IP67, so I'm keen to keep the holes filled. Obviously that's not possible with the floating rivet nuts.
The other thing about using the self clincing studs is that they come more or less flush with the box outer, so they can't get caught on anything, and there's no faffing about getting the screw the correct length.
I guess one of the reasons I'm concerned about getting the fits spot on, is that I have to press the thing in a vice. I don't have a flypress. I think that the rivnuts, would be a far better bet from that perspective.
I'm in a bit of a quandry about it really. I've been thinking about it some more, and I'm beginning to think that it will be better to put the transistor onto the PCB, avoiding the need for a fastener. The problem with that, is not so much the heat dissipation from the transistor, because that's pretty low. The disadvantage of that is that I then have to put about 20A @ 12v through the PCB, and that's not that clever either.
Arrrgh.
>> Edited by dilbert on Sunday 4th September 21:42
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