Downing’s Screw Post Method
For while now I’ve always had the problem of how to mount buttons, control sticks, screens and other various parts to a casing. Most of the time it involved nylon spaces and a ton of glue and other forms of adhesion, however this proved to be a headache if I ever had to take those components out.
While working on my most recent project, I found a way to make adjustable screw posts that allow you to get just the right height for your tact switch or PCBs. Below is a quick guide that will hopefully make mounting components a bit easier in the future for you, especially if you end up having to take things apart as much as I do.
It should be noted this method will not work in all applications and takes a fair bit of pre-planning to make sure you have the space to work with, but generally speaking, this should do you well in the future.
What you’ll need to get started.
Each project is going to be different and have different heights requirements for their screw posts. In this case, our screw posts are actually going to be standard machine screws. Very tiny machine screws at that but you’ll find the smaller they are, the easier it is to work with. So for this example, here are the materials I’m using.
#2-56 x 3/8″ Long Pan Head Machine Screws.
#2-56 Hex Nuts
Custom Cut PCB mounting board with .088″ holes drilled for the screws.
Plumber’s or Marine Goop
Now, this is just for my specific example, but there are a few things to note before picking out the materials. Though I’m using custom milled PCB, this will work with just about anything flat and stiff, including scrap plastic or breadboard. Once you have your components mounted to the board, then you can begin the placement of the screw holes on the board. Another important note, you will need double to triple the nuts to each screw post. By this I mean that each post will take a minimum of 2 hex nuts, three if the screw itself is too long and the head does not make contact with the top of the board, which we’ll get into later.
When the board is prepped, take the number of screw posts you’re using on the board and place them through the top. Screw on a nut to the bottom of each one, however do not put the screw all the way through the nut. Make sure to leave at least 1 to 2 threads back from being flush.
Take a bit of super glue and dab around the face of the nut, being careful not to get the glue in the threads there by locking the two together. That’s not what we’re going for. Gel Control Super Glue is the best as it won’t run like the regular kind and you can be quite precise with its application.
Now, flip the board over and place over the buttons or whatever it is you’re mounting so everything lines up the way it’s supposed to. One you have it lined up, press down on the screw heads to set the nuts in place. This pretty much aligns the nut as a screw base directly above where the hole in the board where they need to be. Now be careful here though as it’ll only take a slight bump to loosen the glue and screw up the alignment.
Once the glue has set, carefully unscrew the screws from the nut and “boom” there is your screw base aligned nicely.
Next is to make sure they stay there. Superglue alone won’t hold, especially if you screw the screw in to far as then it essentially is just pushing the nut off the back of the casing using good ol fashioned leverage. However, this “Amazing Goop”, either plumbers or marine is absolutely amazing stuff! It holds far tighter than super glue, bonds to everything and stays flexible so that unlike superglue, it’s not brittle at all. Very good stuff indeed. The only downside is it take about an hour or so to cure. Keep that in mind.
Using a cue-tip, take a small amount of the Goop and spread it carefully around the screw edges, being sure once again to not get it in the threads. Also be sure that the Goop won’t come into contact with any of the buttons or components your mounting. Once that’s in place, let it set for at least an hour.
Now this is the part that determines if you need 2 or 3 nuts for the screw post. If the screw itself is the right length that it allows the board to rest up against the head snug while still allowing for the button presses to move fluidly, than you’ll only need two. However, if the screw is too long, you’ll have to thread another nut under the head to take up the space. You could alternately cut the screw, but that leaves jagged edges and chances are you won’t have them the same length which is pretty important.
But, if the screw length is good, place the screws though the screw holes on the board and thread a nut all the way to the bottom of the board, but do not tighten them down yet.
Now, flip the board over and tighten the screws down until it’s flush with the tacts or whatever method you’re using for buttons. You can make slight adjustments this way if your screw is very close to the length needed. If your screws are longer or you need to move the board down further, loosen the nut on the bottom and let it find it’s own level. If you have to do this, you’ll most likely need the nut under the screw head as well to sandwich the board between and keep it secure.
Once everything is in place, tighten the nuts under the board in place and there you have a secure and adjustable screw post system that you’ll really be able to feel.
Again, this won’t work in all situations but with a little bit of planning, you can take away a lot of the mounting headaches when it comes to these kinds of components. Please let me know if you have any questions. Thanks!