Kludge-mounting a 7 segment LED display

I'm confused, you're mounting it to the outside of the box? If so, then put it in a little 'box', maybe.

George H.

A photo of the display would help. ...Jim Thompson

You've not said how large the desktop machine is, nor form factor. (nor whether it is a "desktop PC" or just some "desktop enclosure")

In the former case, consider removing the (or *an*) exposed optical/floppy/disk drive and cobbling a plastic "filler plate" to install in the now empty bay. This can be made to look professional as well as improving serviceability.

Assuming it is NOT a "desktop PC" (masquerading as a drum machine), why not just enclose the display in a suitable enclosure and velcro that to a reasonably blank portion of the front panel (i.e., NOT over something that needs to be accessed in normal operation).

The little, flat "jewel cases" in which you sometimes receive IC samples (usually only 1/2 inch "thick" with a hinged "top lid" that "snaps" to the "bottom lid" when its closed) are easy to carve and have the right sort of aspect ratio (tall and wide -- but shallow) for a PCB.

Add some PCB art?

Fab a small PCB in an aesthetically-pleasing color, use traces and silkscreen to incorporate a design (i.e. band logo) around the LEDs.

You could just 3D print up a wee box to hold the display. It will be ugly though, because the box will have to be around 11mm tall, more like 13-14mm if you want to put a filter in front of the display.

There are thinner displays on the market such as OLED graphic displays.

--sp

Nice, 3D printing a little enclosure hadn't occurred to me. I know a guy...

Just printing up a replacement part for a weed whacker made in 1986.

--sp

Not too bad. Took one iteration (didn't have an original to duplicate).

or used stacked acrylic like this:

mask off and paint on the inside to make a window

Maybe this box?

Double stick tape to case.

Yeah, I think that's the most expedient solution. The price is right!