Blind Fasteners

[Phlatiron]

I have letters of the alphabet that need to be mounted on the wall. Visible fasteners are not allowed. There is no access to the back side of the wall, fastening from the back is impossible. The leters are 6" x 6" x .395" and made of aluminum. They should be fixed against the wall in left/right and up/down directions. This is an aesthetic application and each fastener should be no more than .5" dia, as the letter needs to cover each fastener when in the final position on the wall. I am imagining ~4 fasteners per letter, hopefully achieving a 20+ lb total pull appart force.

Has anyone seen some sort of christmas tree (push pin type plastic fastener used commonly in automotive applications) that is made of aluminum (or?) and has one end threaded?

Looking for ideas, we have gone over many, but there has to be more...

Thanks,

 

[hydtools]

Adhesive-backed hook and loop tape(Velcro).

Ted

 

[MintJulep]

Wall is made from?

 

[btrueblood]

Plunge a dovetail cutter into the aluminum from the backside, then mill vertically one cutter radius less the shank radius. Screw a flathead screw into the wall, and hang the letter by hooking the slot you milled over the dovetail cut.

 

[btrueblood]

Option #2: Drill a hole in backside of letters, glue a Nd magnet into the hole. Drive a flathead steel screw into the wall. Place letter against wall and slide around until the magnet contacts the screw head.

Note, I'm assuming you want the backside of the letters flush to the wall surface.

 

[dvd]

Automotive badges are attached with double-sided foam tape;

http://solutions.3m.com/wps/portal/...8FSO6Q3GD3000000_nid=MHFC47W8JVbeZV5WZ3NX25gl

 

[Walterke]

Does it have to be removable?
Can the wall be damaged in any way?
What's the wall made of?

NX 7.5.5.4 with Teamcenter 8 on win7 64
Intel Xeon @3.2GHz
8GB RAM
Nvidia Quadro 2000

 

[Phlatiron]

The letters will need to be removed, but the fastener can be sacrificial (needing replacement everytime its removed).

The wall is a composite made up of two layers of phenolic prepreg, nomex honeycomb core, and two more layers of phenolic prepreg, totalling ~.75" thick.

Magnets (various concepts) have been modeled, but are lacking "buy off" by the end users. The perception that there is no mechanical interlock holding them to the wall is hard for them to swallow...

 

[MintJulep]

http://www.pencomsf.com/pdf/ball_studs/Ball_Studs_and_Clips.pdf

 

[Phlatiron]

The ball stud concept could work, but we run into fastening issues with not having access to the back side of the wall. We could pot inserts (see NAS1836, etc..) into the wall but then run into leter coverage issues. The letters need to cover all the fasteners.

What about some type of interference fit soft metal pins? A 1/8-1/4" dia pin that has ridges that run axially up and down the length of the pin, that presses gently into each component...

Has anyone seen or used something like this?

 

[MintJulep]

How about something with a continuous rail, like:

You could use a profile with a snap fit.