5.25" Embedded Motherboard PC (Commissioned Build) – Day 11-12
Note, click on images for higher res. versions.
I didn't manage to write up an update yesterday for the couple of hours spent on some teething issues, so I'm combining yesterday's and today's efforts into this update. Oh, and guess what? I don't have the case anymore… IT IS AT THE POWDER COATERS! Yippee.
Panel Fixings/Enclosure
Due to the thickness (thinness really) of the material on the HDD side that the M3 mounting screws screw into, I was concerned about stripping the threads or not getting a tight enough hold, so I spent some tool considering and experimenting with some alternatives and additions. The first was to make little L brackets out of 3mm aluminium angle, ripped down to 8mm x 8mm. Here you can see the ripping process on a piece of 12mm x 12mm x 3mm. A section was cut and placed close to a mounting hole. This is when I realised that it wouldn't work… the 3mm thickness was too thick and would mean the screws would be trying to penetrate the horizontal part of the bracket. Idea scrapped.
In the end, and after agonising over alternatives, I decided to either consider little plates that will be glued in place after powder coating or to replace the M3 screws with 6-32 UNC or 6 gauge self-tappers. As it happens, the screws have a good hold and I understand the powder coating process will actually enhance the grip and rigidity of the alu. The only real area of concern is with the HDD U-channel bracket as I've had to rip the thickness down to 1mm to fit the HDD.
Hole alignment / enclosure alignment
The next process was one of careful realignment. I'm not sure what happened exactly, but the alignment of the exterior mounting holes to the interior holes causes some misalignment between the two parts of the enclosure. I spent a fair time carefully filing the problem holes, including some riveted bracket holes, to get the alignment of panels near perfect.
Example of a misaligned hole. Some were worse. To correct them, I've used a small round needle file to open up the holes evenly around the internal thread or bracket hole, as applicable. This was a real nuisance and quite time consuming, but to achieve near perfection, it had to be done.
Finishing…
Happy that the panels and enclosure parts were nicely aligned, I did some sanding of the bumps and rises and overlaps.
Bevelling the edges
Finally at piece with the case fabrication, it was time to put on the finishing touches before sending it off to the powder coaters…
First I set up a smooth surface on the router bench to alleviate any little bumps with the table surface given that I was using a ball bearing guided 45 degree bevel bit. I used a piece of double-sided fabric tape to help secure the piece of Masonite around the bit area and then a clamp either end.
Whoops, must have forgotten to take a photo of the set up. Sorry. Basically flip that board up and over toward the bit and that was it.
The result of the beveling/chamfering process. Although all this can be done with sandpaper quite easily, I wanted to good 45 degrees to start with.
Then, after some regulated, even sanding with a stiff sanding block and 280grit paper… Hmmm, nice corners.
To the powder coaters!
All seven pieces for powder coating…
Still to do – Post Powder Coating!:
- properly align and affix LCD with double-sided tape (post powder coating)
- properly align and affix side vent with double-sided tape (post powder coating)
- properly align and affix top fan grill with double-sided tape (post powder coating)
- affix little rubber feet (elevating the whole enclosure a couple of millimetres)
- mount on/off switch
- check thread strength and either include or replace M3's with self tappers or glue in little plates, drill and tap.
Ahhh, what a relief. I am so glad this little enclosure is finally at the powder coaters. Don't expect an update for a several days or a week or two… but keep an eye out, because it should be a ripper!
Cheers
GAM