Hi there everyone, Nerdy a.k.a. "Wannabeamodder Jr." here, and I'm finally ready to post the progress made on my build of the "Blast Door Project."
If you haven't seen my dad's post yet, you might want to look there to see how this whole thing got started
Near the beginning of my dad's thread, he mentioned that we would be building two of these things, one for his system, and one for my system. I waited until the final stages of the first build to start mine, so I could see how the idea worked out, since it wasn't exactly spot on with Crimson's original design (we had to make a few changes to adapt it to our build size and case).
When I started work on my build, I decided to take a different approach to building the linear actuator, not because the original design didn't work, but because I was in the mood to...eh..."tinker." I figured it wouldn't be any fun to build an exact copy of what's already been done.
Also, the first build was not without its problems. Even though the basic design was proven to work by none other than Crimson himself, our build had its share of bugs and problems. I suppose this is where years of experience in this sort of thing pays off, eh Crimson?
Among the few problems included instability of the actuator, sometimes too loose on the gear strip, sometimes too tight, the whole motor assembly wobbled too much within the main guide shaft.
Thankfully those problems have been fixed in the first build. I took note of them and set out to make a build that wouldn't have those same problems.
My original design was not too dissimilar from the original plan. It involved the same actuator/guide shaft/gear setup as before, but instead of the motor/gear assembly riding alongside of the main guide shaft, it would ride above it, with arms "hugging" around to the underside, and connecting to the guide piece that slides through the shaft. The gear strip would be on the top of the main shaft. Also the entire assembly would be made of styrene, because, for one, I don't like working with metal, and two, who needs all that metal just to raise and lower an extremely light blast door?
This was my "monorail" idea, which was basically thought of as a means of hanging the center of gravity of the motor assembly underneath the drive gear, thereby keeping it meshed with the gear strip and keeping the motor assembly more stable.
This idea had its advantages and also introduced a new slew of problems to overcome...
It solved the stability issue, but how would the weight of the entire motor assembly hang on just one gear? An obvious balance issue to overcome. Not only that, but size was still an issue as well. Crimson's design wasn't easy to shrink down to use in a standard case. At one point, the first build had a section of the main guide rail that extended out of the rear of the assembly box, and almost touching the power supply! Like the other problems, though, thankfully this one has since then been fixed. I didn't want to encounter the same problem in my build though, so changes had to be made.
So, a few days passed, a few thoughts rattled in my brain, when all of the sudden, an idea smacked me in the face out of nowhere. I was digging in a box of old junk, and I found a model train. HO scale to be exact. I tore open the train, dissected it, and found this:
I didn't get a photo of the train intact, I was too busy brainstorming. Luckily, however, I found a picture online of an intact train with more or less the same setup as the one I dissected.
Pretty much, this one compact wheel unit was the beginning of an entire actuator motor setup. I only had to find a way to drive the wheels.
I began working, and ended up with this:
Essentially, the actuator is...a tug train/roller-coaster hybrid. I have two straight pieces of track, one on top of the other like so:
The tug rides on the top portion of the track, while a guide set of train wheels, attached to the tug, ride on the underside portion of the track, keeping the tug in contact with the track and to keep it from derailing.
Pretty much my "monorail" idea, re-imagined.
Before this photoshoot, I had the guide wheels already attached to the tug, but the attachment method was rather clunky, so I detached them and am currently coming up with a better way to attach them to the tug unit.
Before that, I ran some initial tests to check the power of the motor and to see if it would have enough grunt to raise/lower the door. I gripped the actuator in one hand, the battery in the other. Touched the wires to the battery, and poof. It spat the track out with such force that it nearly hit me in the face from full arms' length!
As for the main case or "box" that the unit goes in, the design is essentially the same as the first build. There were a couple of problems with misaligned parts and warping due to misalignment, angles not being square, etc.. Pretty much the first build was done by the age old method of "eyeballing." Sure a few measurements were used here and there, but most of it was trial and error. I set out to perfect the first design, by measuring and drawing each part exactly to scale in a design program.
Interestingly enough, I didn't use AutoCAD or Sketchup, or any other program used solely for designing and blueprints.
I used Photoshop
I set up the page size to match a standard 8.5 x 11 sheet, and set up my grid and rulers to do 1cm x 1cm boxes, and away I went.
After a few days, I nearly finished the front view.
A few more days and the side view was nearly done.
Of course I have it set up to where you can view/hide different parts/elements of the design, I just have everything unhidden in the pictures.
As you can see, I have designed this actuator to make use of the full length of the track, with no wasted space at all. This let me fit the whole build snugly into a 17.3cm long space.
I still have to design the method of attaching the tug to the door, the mount for the entire actuator assembly, and to redesign the method of connecting the guide wheels to the tug unit.
As for progress on the box construction:
One aluminum CD-ROM shell from random mutilated CD-ROM drive. This will be used as the base for the box to be mounted inside the PC case.
Closeup shot of one of the sidewalls. Notice the shorter blast door rail as compared to the first build. A part of my "smaller is better" motive in this build.
An overhead shot of the sidewall:
After much gained experience on the first build, I opted to build the blast door rails right onto the walls, instead of building the rails separately, and then gluing them onto the walls, as with the first build. This helped out a lot, there is no bowing or bending to be seen from the sidewalls this time around.
Here is an overhead shot of the layout of parts that I have fabricated already:
Progress is going very well so far. Expect an update in a few days. If not Tuesday, then Thursday at the latest. My college schedule this quarter is quite cramped on Mondays, Wednesdays, and Fridays, so I don't get to work on it as much as I would like during the week
Well there you have it. I hope you enjoy my build as much as you enjoy my dad's.