Here's the parts list for the stuff I picked up from small parts for use with our Gumstix boards, including instructions for building 2mm and 3mm non-conductive spacers out of polyimide tubing.  The screws and nuts are basically just #0 at 80 tpi, but the interesting bits are the polyimide tubes and which screw lengths were most useful.

The polyimide tubes are flexible, like straws but obviously extremely skinny straws... not much use for stirring your coffee.  In fact, to get the necessary rigidity, you actually place the 0.0641 ID tube into the 0.0720 ID tube.  Then cut them to length.  I did this mostly by eyeballing it and cutting with wire cutters or scissors, as there is a small amount of compression you can get away with.  If found the 2mm spacers were the hardest to get right as I always tended to make 3mm spacers because they are so small.  I found that a tiny pair of tweezers or needle nose pliers on the 2mm or 3mm end being cut would keep it from flying off into the distance when cutting.  Razor blades would mostly crush the thing when I tried it, but my blade is probably dull.  Anyway, these tubes are just barely bigger than the #0 screws and they are unnoticeable once installed.

I found a hand drill "pocket drill" thing (looks like http://www.hobbylinc.com/htm/ddd/dddpds12.htm).  The largest bit from that set is just large enough for #0 outside diameter.

As for the screw lengths, I have found that the only ones I actually needed were 5/16" (for one screw that went through two boards, 2mm spacer and left room for a nut.  I ran the head of the screw from the Gumstix board through the netCF board and put the nut just next to the CF card pins.  The other holes went through all three boards, and I used the 1/2" screws for those.  I think 7/16" would have been better but they don't sell that size.  3/8" was definitely too small.  When I used 3/8" screws they would go through all three boards and (before I reamed the holes) they would tap into the STUART board.  However, that proved a poor solution as the stress of frequent handling caused the screws to pop loose so always use a nut.

BTW,  when mounting the  boards to a case, I used netCF's holes, reamed out a bit.  I used #2 screws and nuts for securing the boards.  You can only use two of the screw holes, however so it's not rock steady.  Some epoxy or hot glue?  I don't know.

Cheers,

Mike

[www.smallparts.com]   
--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Item........... WPT-072-12 (or TWPT-072-12)
Description.... POLYIMIDE TUBE TP WL .0720 ID
Price.......... $12.50 (2 PCS 12" LONG)
--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Item........... WPT-064-12 (or TWPT-064-12)
Description.... POLYIMIDE TUBE TP WL .0641 ID
Price.......... $12.50 (2 PCS 12" LONG)
--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Item........... MPX-0080-03P-10 (or MPX-080-3P-10)
Description.... S/S MACH SC 0-80x3/16 PHIL PAN
Price.......... $1.05 (Pk/10)
--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Item........... MPX-0080-04P-10 (or MPX-080-4P-10)
Description.... S/S MACH SC 0-80x1/4" PHIL PAN
Price.......... $1.10 (Pk/10)
--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Item........... MPX-0080-06P-10 (or MPX-080-6P-10)
Description.... S/S MACH SC 0-80x3/8" PHIL PAN
Price.......... $1.20 (Pk/10)
--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Item........... MPX-0080-05P-10 (or MPX-080-5P-10)
Description.... S/S MACH SC 0-80x5/16 PHIL PAN
Price.......... $1.20 (Pk/10)
--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Item........... MPX-0080-08P-10 (or MPX-080-8P-10)
Description.... S/S MACH SC 0-80x1/2" PHIL PAN
Price.......... $1.25 (Pk/10)
--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Item........... MPX-0080-10P-10 (or MPX-0080-10P-10)
Description.... S/S MACH SC 0-80x5/8" PHIL PAN
Price.......... $1.60 (PK/10)
--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- Item........... HNX-0080-C (or HNX-080-1C)
Description.... HEX NUT S/S #0-80
Price.......... $7.95 (Pk/100)
--- --- --- --- --- --- --- --- --- --- --- --- --- --- ---



Dave Hylands wrote:
HI Alex,

  
Maybe this has already been discussed on the wiki but I'm still confused
about it; I'm almost done with the project I'm working on and now I'm
starting to think how to pack the gumstix and what case use.

I'm using a gumstix 400 connect + cfstix + UART (2 serial connector). In
future I'm planning to use netCF n plac of cfstix.
Does anyone have found a way to mechanical fixing the gumstix sandwich
together in a "professional way" and found a nice looking case and a way to
fix the gumstix sandwich in it?
I would like to ship to my customers a pakage that must be resistant and
that they can play with (plugging and unplugging connectors and CF without
breaking it).
    

When I started playing with my robostix/gumstix/netstix stack, I found
the stack to be quite fragile. By creating a little spacer gizmo along
with a single screw, the whole stack became quite robust in terms of
being able to handle it.
http://www.davehylands.com/Machinist/Projects/Gumstix-Spacer/

Now that I've used it for a while, I've come to realize that what I
did a bit overkill. All you really need is a 3mm and a 2mm spacer.
There's no need for the spacers to be connected together (as mine
were). The spacers can be made out of anything that's non-conductive.
Wood or plastic should work fine.

I used a 1/2" 0-80 screw to hold it all together.

--
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/


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