OT: Stainless box "cap"/mounts

3M makes some nice permanent-adhesive double-sided foam sticky tapes, and a soft-steel washer permanently mounted to the stainless should work (and not show any marks). I've also used velcro...

I'm not sure I follow?

Imagine a five sided box: front (the side that faces the user if wall mounted), two sides, top and bottom. "back" is open and fits OVER the electronics, snuggling up against the board onto which the electronics are mounted. I.e., the portion of the box that touches the board (and that is the only portion of the box that touches *anything*) is just it's "edges" -- i.e., the thickness of a piece of stainless.

Where do I put the washer? Tape? Velcro?

wall

W W WB WB---+ WB | WB E | box with Electronics inside (on board) WB E | WB | WB---+ WB W Board W

Steel Tee Nuts into the back of the wooden boards (bread boards?) in the corners, such as: Some kind of standoff (probably plastic or nylon) threaded into the t-nuts. PCB are mounted on the T-Nuts. Depending on available room, you only need one T-nut and screw combination to hold the cover to the wooden board. The problem is that you also need a clearance hole in your PCB for the mounting screw. You can work around that by using threaded standoffs, drilling holes near 4 corners, and sharing the board mounting hardware with the cover screws.

If you can't get to the back of the wooden board, you can use various blind fasteners or screw nuts such as: However, they only work with fairly thick (>0.50") boards.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Mounting the PCB's to the boards is easy; I left myself a lot of space for these "units" as most of them have lots of individual field wires that need to be terminated on the PCb (barrier strips) as well.

Wouldn't be effective unless located in the exact center (underneath the handle that my buddy thoughtfully installed on each cover!). I thought of that as one of the boxes mounts "upside down" (i.e., the board to which it mates is on the ceiling). This was suggestive of a ceiling mount light fixture: put a threaded rod in the center that feeds through a hole; then a nut on the rod clinching the cover up to the board!

But, that puts a bolt right in the center of the PCB, etc. And, means I have to have the location of the PCB "settled" before I can fab it. If, instead, I keep the "cover hardware" around the periphery, I have a lot more flexibility in what goes under the cover -- and where!

[E.g., one cover hides several 66 blocks so *they* are a potential conflict -- along with all the loose wire connected to them! Another has a large battery tucked in a corner. etc.]

I also thought of using four of these -- one per corner -- but the elegance of the cover is lost when you start cluttering up the surface with mounting hardware. (that's why I have focused on using the *sides* or top/bottom for that)

Boards are mounted to the wall (ceiling, etc.) with toggle bolts. So, I can easily remove them (with the *possible* loss of the associated wings -- BFD)

I'm thinking more along the lines of magnetic or friction/snap fit along the (2 or 4) edges.

pairs of neodmium magnets or velcro tape.

___________________ |.......... |.......... |.......... |.......... | mmm | mmm | //////////// | ///////////// |___ ///////////

|__ cover

..... ..... foam block glued in position mmm magnet (glued to foam or wood) ///// wood ////

--
umop apisdn

Glue a standoff block (or two) on the wood base that nearly fills the space from base to the large (12 x 12) face of the cover. Attach the iron strike plate (washer or somesuch) with permanent adhesive inside the face, and the magnet to the block. Or, use some construction adhesive to glue mounting ears to the cover sides, on the inside where they won't show, and put the velcro bits there.

What sort of adhesives will stick to stainless? (I've never tried it) Epoxies?

I.e., I could adhere magnets to the inside edges with "strike plates" on the surface of the board so the cover "grabs" the board.

It's actually more like this:

___________________ |.......... |.......... |.......... | mmm || mmm \/ mmm ///////////////////// ///////////////////// /////////////////////

I.e., the board is larger than the box cover. And, the box doesn't have a "lip" (I *think* that's what you were drawing at the lower left corner in your illustration). Rather, the stainless "edge" is folded back on itself (the '\/' in my illustration) so the "cut" edge is not exposed.

In practical terms, it means there is no "flat surface" to mate flush to the board.

I'm going to explore:

___________________ | | | | mmm ||mmm \/===== ///////////////////// ///////////////////// /////////////////////

=== metal "striker plate" fastened to board

For the magnet, I think I can use some COTS "magnetic latches" used to hold cabinet doors closed (e.g., kitchen cabinets). Magnets adhered to inside side of box.

I'd also considered:

___________________ | | ( |BB| | | || | \/ | ///////////////////// ///////////////////// /////////////////////

BB a blob of some sort (round head screw, etc.)

The vertical member terminated in '(' would be a spring-steel finger that deforms inward to allow the "blob" to pass, then snaps into place

*beyond* it to hold the box cover against the board.

Have to wait until I can get to the hardware store. Pro-bono day, today.

The cover plate is probably slightly flexible, which would crack any of the hard adhesives like epoxy. I suggest something flexible, like silicone rubber glue (not caulk or gasket) which works well with cleaned stainless.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

There are pliant epoxies.

Den tirsdag den 10. marts 2015 kl. 02.09.15 UTC+1 skrev Don Y:

two vertical strips of wood that fits snuggly inside, sligtly beveled on the side facing the board so the folded over edge can grap on

-Lasse

Not really. Each "side" is roughly 2"x11". So, you have a 2" strip that has a "crease" along one edge (i.e., as the side folds to become the *face*) and the other edge (i.e., the edge that rests against the wooden board) is folded over on itself (so, 1/8" thick). And, of course, the "folds" as the strip goes around to become the adjacent sides.

These are the surfaces to which I would envision bonding any fastener(s). I can't imagine the sort of abuse the covers would need to experience in order for those small surfaces to be deformed (temporarily) in any way.

Remember, it's just a *cover*. It only has to support its own weight!

Thanks, I'll keep it in mind. I'll have to see what sort of "catches" I can find that are appropriate. I can recall some with a hole drilled through them (center) and metal plates on each side of the magnet (to do the actual grabbing). If that's the case, I may be able to just put a screw/rivet through that hole and be done with it.

Infeasible; that hole has a loose-fitting rivet that allows the pole pieces (metal plates) to float a few millimeters in any direction, and unless all dimensions are precise beyond reason, you NEED that loose fit.

But, as long as I don't "sock it down, tight", there shouldn't be a problem, right? E.g., use a lock nut with nylon insert (resists loosening even when not locked down fully)

I paid five bucks for 100 tiny ones, 5mm diameter 1mm thick good for maybe 5N force between a pair, less off-axis, it's hard to measure.

--
umop apisdn

ah, can you get a thin clip into the U fold? | | ___ || \ |||# / |||#| |||#( |||# ' |_| perhaps you could clip magnetic catches to lip, eg use with those "clip-nuts" over the ears.

--
umop apisdn

I don't think the folded over portion is prominent enough to be much of a "grab" -- especially if there is anything pushing outward on the box cover (e.g., ratsnest/service loops of wires) or for the one that will be "upside down".

The box is ~18 gauge 304 (about 0.050"). The folded over portion is about 0.120" thick at the widest point of the "fold". So, you're dealing with ~1/16" difference -- once you get *past* the folded over portion (i.e., about 1/2" up the side

| | | || || || || \/

I'm going to try the magnetic catches/latches when I get a chance to visit hardware store. It seems the simplest. Anything that counts on deformation or springiness eventually proves to be a disappointment!

If you have the clearance, use wedges - 1 pair per box. One wedge mounts to your wood board, the other inside your box. Diagram:

Wall || || ||____________ ||| | |

Oooo! That's an idea! I suspect there isn't enough of a gap to wedge something in there. These are really well-made boxes (as is usually the case with "G-jobs", right? It's the stuff you do 9-to-5 where the corners get cut! :< )

I'm going to pursue the magnetic catches/latches. I suspect they will be larger than the "folded over" portion -- so, I'll have to put a shim behind the portion where the foldover is absent.

I'm just annoyed at myself for not having considered this when I asked for the favor. At the very least, he could have offered suggestions that would have been *easy* for him to implement (at that time). E.g., a lip along the inner edge, etc.

Can't complain. Without the freebies, I'd be trying to fashion covers out of *cardboard* or somesuch! :) So, thank the nice man and deal with the problem yourself...