Dremel weekend

posted Aug 6, 2012, 7:58 PM by Andrew Stock   [ updated Aug 6, 2012, 7:58 PM ]
Allll righty! Time for some pictures! I'll spare you the dialog and jump right into it, commenting as I go and letting the pictures do most of the talking. 

First of all, here was that picture I promised of the crude acrylic barrier I made for the radiator testing:

It also served to show just how ugly an acrylic weld with superglue can be! 

Anyway... on to the case cutting process!

Step 1. I took off the brackets and labeled the case walls, so I would remember which side is which... and not nearly cut the wrong pattern in the wrong side of the case like I almost did. 

Step 2. I isolated the first case wall that I wanted to cut in sketchup, turned it BACKWARD (reasoning explained later) and switched the face style to 'wireframe' so that I could see the cuts I wanted to make "through" the design, and turned the perspective off so that I would get strait lines. Then, I set the camera view to "RIGHT" for this particular view and printed the design out.

Step 3. With the design printed out to scale, it of course spanned multiple pages... so I had to do a bit of "arts and crafts" and cut up all the pages / tape them together. As I went, I taped them to the inside part of the case wall. This would serve as my template, showing me where to cut. 

As I went along taping, I became acutely aware of a problem. The sketchup dimensions were not quite lining up with my case wall!  This caused the design to fall behind the supporting braces, which I cannot interfere with...

A bit of re-measuring confirmed that indeed my sketchup file was not to scale which made me temporarily very sad. Then, I realized it was just a matter of calculating the difference in each dimension as a decimal, and scaling the dimensions of the sketchup to a factor of that calculated dimension. Not too bad!

I noticed that when I selected a grip to resize, I could just type the percentage of size I wanted for each scale, and it would just resize it automatically to that size. Handy! With the sketchup now 'to scale' I re-printed the case wall and went through taping it together again. I lined it up on the case and made some small marks, then cut the pieces out.

Much better! Things actually... well... fit! 

Step 4. With the design all taped down, it was time to break out the Dremel and start some cutting! I used an old two post server rack I had to serve as a hanging mount for the Dremel and power... I have that nifty cable that extends the Dremel into a much smaller and workable hand tool, so this kept the actual Dremel motor suspended in air where it could stay cool and out of the way. 

Much like painting with spray cans, Dremels work best in multiple thin passes. I started with a quick pass... just enough to cut the paper and score the surface, giving a small groove in the case wall to serve as a guide for future passes.

Step 5. All traced, paper removed.  Now for some more serious cutting!

My support team didn't particularly enjoy the sound of the Dremel... but they were happier out here with me than they were alone in the house, despite the fact that I was right on the other side of the door... so they got to sit in my garage and watch/listen. 

First pass down... and I was out of disks.  The kit only came with one 'regular' metal cutting disk, and all the store had at the time was 'thin cut' metal disks... which worked GREAT for cutting small clean lines as they were only half the thickness of a regular disk... but only lasted like 1/5 as long. I could SEE the disk getting smaller as I used it. I think part of the reason they got chewed up so fast was because my case walls are actually rather thick... about 3mm of solid aluminum. Much thicker than your standard steel case wall anyway. 

The regular disk is the biggest one, the rest were thin cuts... anyway, I tried a different department store and picked up another pack of 5 thin cuts, as well as 5 regular cut disks. 

Anyway... more cutting... and more cutting... finally! All cut out: 

You'll notice I was cutting it over a large bin. That was to keep from damaging the surface I was working on... it also helped the case wall disperse heat a lot better, as it was getting rather hot with all the cutting I was doing. It also helped get the surface up higher, so that I could work while standing comfortably. Important, seeing as it took me like 6 hours of cutting to get this far. 

The cuts are obviously still a little rough, too. There is only so much accuracy you can achieve with a rotary tool screaming along at 30k RPM. 

On to tracing the bottom part, and starting all over! At least this part had only four intricate cuts (the curved lines) so it went quite a bit faster.

A little wobbly, but not bad for a free-hand job!  I knew this corner part was going to be the most tricky, as it would be somewhat fragile. Also, because the design needed to be a mirror image to remain symmetric, it would be really easy to tell if it was off by even a millimeter. 

First pass cutting a strait line free hand along the bottom section... looks actually rather clean from the 'front' side of the case, no? That's the whole reason behind reversing the image, and cutting from the back side. The front side will come out MUCH cleaner, and you will avoid having to repair all the nicks and cuts (not to mention if the Dremel gets caught or skips across the surface, as it often did.) 

Cutting and cutting and cutting... I opted to wear a breather shortly into the whole operation, as I figured inhaling all that aluminum probably wouldn't be a great plan. The goggles are obviously important too! 

There we go! All cut out! Rough cutting, complete!

Step 6. Time to remove all the masking, and see what kind of mess I made! 

Pretty wobbly...  Especially obvious since there are so many lines so close together. Note, there is a slight "fish eye" effect due to how close I had to get my camera to show the lines... couldn't find a setting to reduce that. 

Hmm... how should I go about making it more strait? How about comparing it to something that is known for being strait? Metal ruler time!

I found the 'lowest' point in the line, and aligned the ruler with those low points... this exposed the areas that needed a bit more work. Time to mark those areas with a trusty pencil.

Step 7. There we are. Defects: exposed. Now time to grind it down with a trusty old hand file! So I started filing... and filing... and filing... man... I am going to gain some serious muscle mass over this much filing!  Nerds aren't cut out for this kind of physical activity.  Anyway, after a few minutes of filing, I ended up with this:

Much better!  Only... a lot more to go.  Filing... Filing... Filing... first small part: done!

Looking much better! (minus the fish eye lens effect )

At this point... my spectators were very bored. 

Finally! Done filing!

And here's how it looks (roughly) on the system. Note, I'll be putting mesh in the bottom area, and the thin lines will be filled with acrylic. 

Hope you enjoyed the process! It was quite an adventure for my first time really digging into a case mod like this. I'm pretty happy with how the design came out, and I think it will look even better when I get the acrylic lines figured out and filled in. I did some work on that as well this weekend... but I think I'll save sharing it for when I have something more presentable. 

Thanks all! And as always, feel free to comment on any ways I can improve the process or the results! I of course have the other case wall, and the front/top of the case still left to do!