Stacking PCBs on long bolts

[jwillans]

The midibox setup I am planning will have 4 cores and 13 modules.  I'd like to stack the modules in maximum groups of 4 to conserve space .  I'd like to stack them in such a way that there is room to connect/disconnect IDC plugs to the module headers.  I have looked around at PCB spacers etc and they all seem too small to do this.

Here is an idea I have, I'd be interested to know whether it would work.  I am planning to get some long bolts which are narrow enough to fit through the PCB mounting holes, and stack the PCB on these seated on nuts - one below and one above each board.  This way I can adjust the spacing between the modules by adjusting the position of the nuts.  Is this something that has been tried before?

Thanks,

James

[Wilba]

That should work fine, some of those lock washers will stop the nuts coming loose... the ones that look like a ring that's split and bent apart.

But have you considered using IDC headers with 90 degree bends, so the connectors fit horizontally?

[Sasha]

I am planning to get some long bolts which are narrow enough to fit through the PCB mounting holes, and stack the PCB on these seated on nuts - one below and one above each board.  This way I can adjust the spacing between the modules by adjusting the position of the nuts.  Is this something that has been tried before?

James, I wouldn`t recommend this method because it takes much more effort to make desired distance between PCBs than simply staking few regular plastic spacers. I made my Endorphin completely  that way... all sub-panels and PCBs. You can find those spacers in different lengths. I combined 5, 10, 15 and 20mm long spacers with 2mm nuts to get what ever high I needed, and believe me, Endorphin have so many different levels to adjust.

But have you considered using IDC headers with 90 degree bends, so the connectors fit horizontally?

I used this angled headers before and they are a way to go if you have got no space. Of course, they are only useful  for connectors positioned at the sides of PCB.

[jwillans]

Would M3 threaded rods be appropriate for the standard SmashTV PCBs?  I am assuming that M3 stands for 3mm diameter?

Thanks,

James

[Sasha]

Yes, 3mm screws or threded rods are appropriate for any PCB mounting holes.

[cimo]

hi

i agree with SASHA, i used plain steel 2 mm screws and bolts (hard to find!) and plastic spacer (bought 1 meter and cut at need).

Simone

[jwillans]

Cimo - Where did you source the spacers that you can cut to length?  This is exactly what I am looking for to fit 3mm rods.

Thanks,

James

[cimo]

hi

i ve bought it at a shop where you buy stuff for scale trains, radio controlled cars and airplanes etc. not really sure about the proper name..

BUT it will fit 2 mm screw and it s quite thin so it will only work for 1/1,5 cm distances, over that the whole thing would probably be too unstable.

ANYWAY they had other kind of pipe to be sold per meter, different materials and i am sure you can find a similar shop where you live, otherwise take a trip to the amazingly beautiful city of Ringsted,Sjaelland,Denmark and remember not to miss the best Danish  pastry : the Froesnapper.

Another thing you may wish to have a look at is this guy called SureElectronics on Ebay.com, he sells a box with different screws, threaded spacers, nuts etc all M3 sized.If you plan to build up many layers of PCBs threaded spacers are better for the stability.

If you re looking for really thin design (i managed to stack 2 PCBs with encoders and leds in 1 inch!) then go for the plastic spacers and use bolts on top and bottom of EVERY PCB stacked, that will ensure that your pile won t swing around.

In my case it went this way (starting from the bottom):

Flat head screw/throught the bottom of the box/bolt/spacer/bolt/PCB/bolt/spacer/bolt/PCB/bolt (front panel is independently attached to the box)

but you can go the other way round, starting from the front panel, that make more sense in most cases.

Cheers

Simone