Preferred method for mounting PC boards in chassis?

[spatten]

Anyone have a good standard of work for securing PC Boards in chassis?

I'm working on a few amplifiers - and bought a set of M3 nylon standoffs. I'm thinking of securing the boards with nylon bolts to these standoffs, and then either gluing the standoffs to the chassis- or drilling M3 screws into the standoffs from the bottom of the chassis. But that means countersinking and lots of through holes in the chassis.

Am I overthinking it?

THanks in advance,
Scott
.

 

[rayma]

I'm thinking of securing the boards with nylon bolts to these standoffs, and then either
gluing the standoffs to the chassis- or drilling M3 screws into the standoffs from the bottom
of the chassis. But that means countersinking and lots of through holes in the chassis.

Standoffs are easy, and they come in aluminum, steel, nylon, and in all sizes, threaded or not.
What's not to like? There's nothing wrong with screw heads on the bottom of the chassis.

 

[spatten]

Thanks Rayma.

 

[rayma]

Thanks Rayma.

It can be tricky to accurately drill holes for the pcbs.
I've used the pcb as a template, placing it on the mounting surface,
and tracing the mounting holes directly on the metal.
Then center punch the marked hole locations before drilling.

 

[nezbleu]

And it's easier to use the PCB as a template before it's populated! Seems obvious, but I always tend to put off case work until after boards are stuffed and tested, then the boards don't lie flat to mark the holes. One of these days I'll do it the right way.

 

[jcx]

I previously had work access to DRO Milling Machines and now maker space access to similar/better CNC so I've used threaded standoff mostly with the ability to put hole patterns accurately where needed

but there are really good acrylic tape adhesive base standoffs - even with push-on snap ends

Sturdy Support Adhesive Lock-in / Release PCB Supports

I would definitely go with them if I didn't have access to the accurate DRO/CNC tools

 

[AndrewT]

......................There's nothing wrong with screw heads on the bottom of the chassis.

If it's an insulated Chassis then every screw head falls into the category
"all exposed conductive parts" !
Be aware, each metal screw head would need to be connected to the PE protected Chassis/metalwork.

 

[jwilhelm]

I previously had work access to DRO Milling Machines and now maker space access to similar/better CNC so I've used threaded standoff mostly with the ability to put hole patterns accurately where needed

but there are really good acrylic tape adhesive base standoffs - even with push-on snap ends

Sturdy Support Adhesive Lock-in / Release PCB Supports

I would definitely go with them if I didn't have access to the accurate DRO/CNC tools

I use a mill with readout too. It's nice not needing to "adjust holes" to make the screws go in.

I don't think I'd trust the adhesive mount standoffs. Nobody has gotten tie wrap bases to stick reliably for long periods of time near heat yet. This is likely the same glue. If the mounting surface is raw aluminum, nothing will bond well to it either.