Scion xB '06, in-dash Atom 330, Lilliput 889GL; details, pictures, links. Index: pg 1

**rdholtz** · 06-02-2009, 06:17 PM

Adding "Pop" Rivets

When I was writing about tools for metalworking (post #614), I said this:

Originally Posted by rdholtz

. . . somehow I'm just not a big fan of pop rivets. They have good aspects: the tools are inexpensive, the rivets are inexpensive, they have good shear strength (when they're stressed perpendicular to the axis of the fastener), and the installed rivets look nice and clean from the front. But they have some aspects I don't like: they have low axial strength (when they're being pulled apart parallel to their axis), the backs of the installed rivets are ugly, and they're a bear to drill out if I decide to change something -- and that's pretty often in development projects. I use pop rivets sometimes, but I think they're only okay.

Now, less than a week after writing that I'm "not a big fan of pop rivets", I have a good use for them: holding the aluminum angle to some of the panels on my "no-bend" chassis.

I definitely want to be able to disassemble the chassis. But I can leave the angles permanently attached to some panels, and that's a good use for pop rivets. My plan is to attach the angles to the top and bottom edges of the side panels and to all four edges of the end panel. Then I can assemble those parts with 6-32 machine screws and nuts.

Now I need to get back into Sketchup and do a redesign for the no-bend system.

**HiJackZX1** · 06-03-2009, 03:09 PM

OMG, I am so turned on by sketchup..... thanks for introducing me to it. Google has made it to so easy to understand. Now time to work on freeflashstuff's case.

**rdholtz** · 06-05-2009, 08:43 AM

Originally Posted by HiJackZX1

OMG, I am so turned on by sketchup..... thanks for introducing me to it. Google has made it to so easy to understand. Now time to work on freeflashstuff's case.

Glad you like it. I'm gradually getting the parts designed for the nothing-but-sheet-metal-and-aluminum-angle case. I'll have pix soon.

**HiJackZX1** · 06-05-2009, 01:41 PM

Originally Posted by rdholtz

Glad you like it. I'm gradually getting the parts designed for the nothing-but-sheet-metal-and-aluminum-angle case. I'll have pix soon.

Cant wait to see. Im doing all the new cable runs in my car, there is alot, but I'll get through it.

**rdholtz** · 06-06-2009, 10:24 AM

Parts for the No-Bend Chassis

One of the things I've been doing while I'm away is making chassis parts with basic tools. I'm also banging away in Sketchup, modifying the original design to be flat panels and aluminum angle.

After I realized I'd need the pop rivet tool, I noted that I'd left mine at home; that's okay, it was tired and only semi-functional, and I needed a replacement. So I stopped at my favorite hardware store, one of the real old-time hardware stores that has everything imaginable: Casler's Hardware in Jackson, Michigan. Dad introduced me to the place over 50 years ago, and I've always enjoyed it. Back in the corners of the store, it still has a vague antiquey old-hardware-store smell, which, for me, gets an almost visceral reaction: I just know I'm going to like the experience.

Well, the people at Casler's were their usual friendly selves, the prices were good, and I got just what I needed: a pop rivet tool ($14) and a bag of 1/8-inch (3mm) diameter aluminum pop rivets for 0 to 1/8-inch (0 to 3mm) material (50 for $2.00). My joints will be two pieces of .042-inch (1mm) stock, so that's .084 inch (2mm), leaving plenty of margin between that and the .125 inch (3mm) maximum.

The basic chassis shape is 4.5 inch H x 7 inch W x 9 inch D (H = height, W = width, D = depth). The sides are 4.5 x 9, the bottom is 5 x 7, and the top is 9 x 7. I'll use the sides I made for the original design, plus the top and bottom panels I completed yesterday.

I still need to lay out the end panel, which is the only one that varies at all from simple dimensions. It's 7.08W x 4.5H inches. The end panel is slightly longer because its width needs to include the width plus the thickness of the sides, so 7.000 + 0.042 + 0.042 = 7.084 inch, meaning the actual box will be almost exactly 180mm, the standard for DIN boxes. It's also way too high, at 4.5 inch, instead of the 2-DIN standard of 3.94 inch (100mm), but I have the height in my dash, so I'll use it.

These parts are being filed by hand to their final dimension; even though I'm very careful, there's no way I'm holding .005 tolerance. So the final dimension is roughly 7.08, and I'll make sure it all fits as I assemble.

Until this morning, all I'd used was the ruler, scribe, saber saw and file. Then I pulled out the drill and made the corner hole so I could cut the notch in the bottom panel that fits around the wiring bundle, and filed away until I got it smooth enough. It's tough to make a curved surface smooth with a flat file; if you try this, I recommend you consider getting a round file, too.

Here are the parts I have so far; these are the bottom and top panels and the two sides.

Click image to enlarge.

Yes, it's a lousy picture; you have to click and enlarge for any detail, and the lighting is poor.

You can see I'm using recycled aluminum for the panels: the right end panel has an old IBM part number stamped into it. I laid out the top panel on the scrap part so the hole that was already there can be used for one of the fan mounting screws, though I'll have to drill it out a bit larger.

**rdholtz** · 06-07-2009, 02:11 PM

More Chassis Parts

I sawed the end panel and filed it to size. This part -- unlike the others, which are aluminum -- is 22-gauge aluminized steel. I also cut and filed the aluminum angle parts for the end panel, and marked them for drilling. These will be riveted to the end panel, and will slip inside the side, top and bottom panels, which will be screwed to them.

Here's how those parts look:

Click images to enlarge.

Here's how they'll go together:

You can see a slight overlap all around; it's the thickness of the material where the top, sides and bottom will fit, and should give the chassis a nice, smooth look.

**rdholtz** · 06-07-2009, 11:30 PM

Pop Rivet Lesson

I planned to use pop rivets to permanently attach the aluminum angle parts to the end panel and to the top and bottom panels, so I got some 1/8-inch (3mm) aluminum rivets. Wrong choice. The mandrels break off before the joints are really tight. Apparently, I need stainless steel rivets. Or maybe these are just too cheap to do the job.

I'll know tomorrow when I go back to the store . . .

**rdholtz** · 06-08-2009, 10:54 PM

First Assembled Parts

I had to make a return trip to Casler Hardware. I needed to get the stainless pop rivets, but I couldn't get the kind I wanted. I ended up taking the large-head rivets, so they look simply gigantic installed -- almost like a caricature. Small-head rivets -- also called button-head rivets -- are what I'd have preferred, but these will do fine because they help keep the project on track. I have to remember that this system will be hidden in the dash.

I cut and filed the four angles that rivet to the top and bottom panels. I had originally intended to attach them to the sides, but I like the idea that, by riveting them to the top and screwing them to the sides, I'll be able to unscrew them and remove the top, leaving clear, unobstructed access to the interior.

I got all the rivets in. Here are the sub-assemblies so far:

Click image to enlarge.

The sides are in the upper corners, and the mainboard support angles are right below them. The top is in the middle, the bottom is on the lower right, and the end panel is on the lower left. I forgot to put the power supply supports in the picture, but they've been in a previous shot.

All the parts are finished, except for the top panel; I still need to cut and drill it for the fans.

Next is drilling for the 6-32 fasteners.

**rdholtz** · 06-09-2009, 04:42 PM

First Time Together

Here's the first time I got the parts taped together to see how it will look when complete. Funny thing -- it's starting to look like the Sketchup drawing.

Click image to enlarge.

You can see what I meant when I said the rivet heads are huge. These are really intended to spread the load over a wider area than is necessary here, but they were what I could get, and I wanted to keep working.

I have to cut the fan holes, and drill for all the 6-32 machine screws and nuts. Then it's time to start laying out the computer part installations. Woo-hoo!

**rdholtz** · 06-11-2009, 12:00 AM

Machine Screws and Nuts Added

I went back to Casler Hardware again to get the 6-32 nuts that complete the supply list. I forgot them last time.

I decided to go with stainless steel nuts; the cost difference was $.60 for the project, so it was an easy decision.

All the basic fasteners are in. Here's the result of that:

Click image to enlarge.

I still haven't cut the holes for the fans. I also have to get the mainboard rails and PSU rails mounted.