... my own oversized projects end up in an appropriate rack mountable chassis from my bone pile ... broken network switch ... can be hacked ... front panel fashioned out of a another piece of sheet metal.
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PCBs are typically laid horizontally. And anchored into place with small screws countersunk into the bottom.
I mostly agree
. My preferred solution is recycled 1U full width Netgear rack mount boxes.
After stripping out the guts, there are three pieces - the base, top cover, and a front panel. Top cover holes are patched when shielding is important. The PCB standoffs in the base generally get in the way, and are pressed into the box. So using a drill stand, and a large diameter bit I drill them off reasonably flush, then remove the remaining metal using a 6mm end milling bit with the drill press running as fast as possible. The steel base is then painted with an enamel paint for corrosion protection.
The front panel is a separate piece that can be patched with Aluminium bar, or steel plate from another box. Holes can be enlarged with a nibbling tool.
Depending on what I'm trying to achieve, I will attach plates inside or outside with
- Stainless Steel or Aluminium rivets for corrosion resistance,
- 3mm screws and nuts (again, I gave up on Nickel plated screws a long time ago and use Stainless Steel), or
- 3mm screws tapped into a thicker Aluminium (3mm) plate (generally inside the box).
I do have a 300mm guillotine which helps a lot in making cover plates.
I have tried a few different methods to fit PCBs and components into the box. Generally, whatever is attached to the base is fixed with rivets to keep the base as flush as possible (projecting screw heads would interfere with other boxes in the rack). So if PCB standoffs are called for, they can be tapped into a 3mm Aluminium plate which is then riveted to the base.
My preferred solution to mounting PCBs is to make up a couple of angle brackets with card guides on them. They are spaced 108mm apart, and a 100 x 100mm PCB slips into the case from the front, with switches etc along the front edge, and power to the rear. Dimensions are fixed by JLCPCB cheap deals. (I started designing 50 x 50mm boards fitted into "margerine" boxes. When the larger sized board became the standard cheap deal, I was lost in the woods. With the rack mounting scheme, I'll just move the card guide brackets
. )
Lately, I've been experimenting with 4S LiIon packs. I did play with 18650 cells mounted on tagstrip, but now I look for laptop battery packs. I do enough disassembly to get to the charging PCB, and solder directly onto the cell weld contact points with wiring to my preferred charging/discharging solution. I remove as little insulation etc as possible. Two packs can fit into a full width case. They could be stacked, but if possible, the original mounting holes are used to rivet to the base.
The finished result is generally "prototype" neat, but I'm not aiming for production quality.