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

Originally Posted by 1000101

On your first page, It shows your Fiberglass dash work.. How did you go about doing this? it looks really good, what did you start out with as a mold an or did you just paint the original dash?

If you mean the dash that's painted red, that isn't mine; it belongs to fixerofallthing. He posted the picture in my worklog to show the way he finished his dash. Unfortunately, that's the only picture of his dash; his worklog doesn't show any others. He used an epoxy to bond the parts.

The Scion dash is polyethylene. I've tried a few adhesives, but they don't adhere to polyethylene, so I'm using plastic welding. It's slow, but seems to work very well.

I read about your fiberglass work in your worklog -- it's looking good.

You might also try this thread, in which GiZaK talks about ABS work.

If you decide to try building with plastic, see if there's a plastic materials dealer in the area, rather than buying some sort of relatively expensive manufactured object made of the material you want. See Post #59 of this worklog for information about that.

Head Unit Support, Version 3

Yesterday, I took Version 1 of the head unit support back out of my car. I wanted another look at the bay, because I wanted to see if I could get rid of the wires that conflicted with Version 2 that I've been planning. Here's how it looks in the bay, with the finger pointing to the attach point:

Click image to enlarge.

Sure enough, I was able to move those wires. I detached the lighter and the passenger airbag display unit from the wires, slipped the wire keeper off its left-side mount, and pushed the wires back through the left hole in the bay floor (it's visible in front of the attach point). I brought them back in the right hole (somewhat visible behind the airbag display), where they don't conflict with the attach point, and put the wire keeper on the right-side mount.

And then the Better Idea light went off. Again.

When I built Version 1 of the head unit support, it was a really complex affair. By the time I had it finished, I'd realized that there had to be a better way. Another Scion owner on MP3Car.com, lostreception, said he didn't think he could duplicate that first effort, and that helped push me to work on a simpler solution. Version 2, called for a deck unit that the HU support mounted on. It took a lot of metal bending to get that deck to follow the contours of the bay in which this goes, as you can see in this rerun of those pictures from Ozzy71's bay:

Click images to enlarge.

Version 2 was still too complex. The Better Idea light went off, and I simplified it, deciding that I could make that deck part shorter, so the deck was only as high as the first two side panels -- the vertical one and the angled one above it.

Now it appears that Version 2 will never get built because an even simpler Version 3 seems like too good an idea.

Version 3 came out of a question: what if I eliminate the deck, build a U-shaped support for the head unit, and simply mount the support to that lone unused attach point in the back of the bay (the one getting fingered in the first picture)? I could run a couple of fasteners into the front of the bay walls to make it really secure, but I'll try it first without them.

Version 3 still has a bit of complexity. The base of the bay tapers slightly from front to back, but there's only about 1/4" difference in the dimensions. I can design that into the U, and I can add a tab for the attach point. If this works as well as it seems it will, I'll build just one part, and have a better, simpler, easier-to-produce head unit support.

Then I can add one or two more simple parts and have a DVD mount, too. If I have my way about it, this will be something that can be pretty easily duplicated. The only unusual tools needed will be some tin snips and a small, light, inexpensive bending brake (inexpensive = $30 or so).

Step one is to make the cardboard prototype. That's next.

Here we go again . . .

Refining the Head Unit Support, Version 3

In the headlong gallop toward simplicity, I gave up some flexibility, and I've been considering ways to regain that. I can still use vertical slots where the HU attaches to the bracket to get vertical adjustment, but that doesn't give me depth adjustment. So how about splitting the sides away from the bracket, using horizontal slots to get that adjustment back? Doing that even gives me the possibility of changing the tilt of the unit, too. I can build it with a bottom U-bracket and separate flat side pieces. The U sides get shortened, and I'll bolt the upper parts to it.

A slight increase in complexity = a great increase in flexibility. Good tradeoff. And another benefit is that the parts can be even simpler.

As I made the cardboard mockup, I realized that I can fasten this lower U-bracket to the right rear side, just as I had planned on the left side. Although there's no steel behind the right side, I'm really just looking for stability, and a bolt through that heavy plastic wall to a washer and nut placed behind it will give me a large load-bearing surface.

That discovery let me change my approach on the taper of the bay. Now I can build the unit square; it doesn't need to follow the shape of the side walls, because the rear fasteners will hold it in place. That's another complexity eliminated. If, in the long run, I decide I need fasteners to attach the front of the bracket into the side walls, I can simply add washers to fill the gap, which will only be about 1/8".

I also realized that I can set the fasteners that join the parts just above the vertical wall surface. If I'd placed them lower, they would have deformed the plastic sides when they were installed.

Here's the cardboard mockup of the base:

Click images to enlarge.

That mockup is really rough, but it's as refined as I need to lay out the sheet metal prototype. The challenge in this was going to be the center flange along the back. Because of the limitations of my simple bending brake, I thought I might have to build a special vise fixture to get that bent, but the flange turned out to be exactly 4" long, and my vise has 4" jaws. Problem solved. The mounting tabs will probably be bent in the vise, too, but the ends can be done in the brake, which is a far better tool for this.

There are just simple flange bends in the side panels, so they'll be mostly cutting, drilling and making slots with the rotary cutoff.

One prototype, coming up . . .

Update: I added more information on "dream machines" for the shop in post #113. Northern Tool has a pretty neat mill/drill/lathe unit that I like, plus a shear/brake similar to the other one I mentioned.

Here's the link to go directly to it.

Prototyping the Head Unit Support, Version 3

Note: This part of the project is taking longer than usual because it's gotten so hot and humid that I just don't want to go into the garage. I'm only working out there in the very early morning; the rest of the day, the shop is like a Finnish sauna, and we aren't even to summer in the tropics, yet. Even a 24" fan doesn't make it livable, so part of my garage time is spent working to rig up a portable air conditioner. At least that will let me put in some longer hours. Whew!

This new design makes it very easy to fit the support in the bay. The horizontal dimension of the head unit is 7", and that's just a bit less than the dimension at the bottom of the bay in the back. In the one-piece design, the support extended out around the head unit, so it was wider, and was a tight fit. In this new one, the base is 7" from side to side, like the head unit. The side panels will bolt to the sides of the head unit and the outsides of the support deck.

I was thinking about taking this directly to the final steel, but decided to go with the lighter material and do an actual prototype, just to be sure it fits well. I'd hate to make a mistake and have to re-bend the final piece and weaken it.

Here's the prototype base in place:

Click images to enlarge.

It turns out that it fit just fine, and my design appears to be right on. That looks a whole lot better than the cardboard masterpieces two posts up.

This prototype is made from the galvanized steel stud base channel I'd been experimenting on. In this test -- where I used a block of wood with a rounded edge for bending -- it worked well. When I used the hard steel edge for bending, the material cracked; it doesn't like tight bends. The bay this mount goes in doesn't have sharp bends where surfaces meet; they all have fillets. The rounded bends I used to match them work just fine in this material.

One thing I realized after making the prototype is that the back corners of the bay are filleted, too, so I'll have to file down the back corners of the base unit to get a good, right-up-against-it fit.

I'll build the side panels next, from the same material.

More on Prototyping the Head Unit Support, Version 3

I did run into one problem on the base. I bent the back flange as a hard corner, not a rounded one, and it cracked. Good thing it's only a prototype, because I'd hate to hear that little "Twoingk" noise it made when it cracked while bending the real thing. It'd be the signal to start over or change materials.

As I was laying out the side panels, I was looking at the places where the holes and slots would go. I started wondering if changing the slots would make them more adjustable. Although I'd originally planned to build the sides with vertical slots where they bolt on to the head unit, now I think I'm going to change to regular holes up there, and put in crossing slots where they attach to the base. I'll put horizontal slots in the base, and vertical slots in the side panels, and see if that gives me the positioning flexibility I want: about 3/8" in each axis (up-down and front-back).

The crossing-slot idea worked really well in building Version 1's long right leg, so I'll give it another go here. One big advantage is that it lets me adjust the tilt angle. That will be especially helpful in this particular installation, because the head unit will be sitting in a part of the dash that curves. It will help later on if I need to adjust the head unit's position to suit the bezel-building process.

I like slots because they provide flexibility. Shade-tree engineering takes lots of flexibility, because there's always a surprise right around the corner. Flexibility lets us look at the surprises and say, "Oh, cool" instead of "Oh, $#!+".

So, here come the slots . . .

Making the Prototype Parts

The basic side panels were pretty simple: cut out with tin snips and drill the top holes. Then it was time for test-fitting. The fit check produced a clear need to trim the bottoms off the side panels, and trim the tops off the base side panels. Once I had them trimmed so they worked together well, I laid out what I thought would be the best positions for the slots, drilled the end holes in all four slot sets, and cut away the webs with the Ryobi rotary tool.

The Ryobi -- it's an 18-Volt-battery-powered version of the Dremel -- is easier to handle when the battery is a little tired. The RPMs come down, and that makes it more docile. That realization prompted me to wish for some sort of speed control on it, rather than the simple on/off switch. I'd really prefer something between dead stop and full throttle. On the Dremel-type tools that are powered by house current, it's easy enough to plug in a rheostat to control speed, but the battery powered version doesn't have that capability if it isn't built into the unit's switch. Maybe that'll be in Ryobi's next model.

A few days ago, when I first decided on slots, I dug through my stash of fasteners and set aside the bolts I needed for the slots. They weren't ideal -- they weren't carriage bolts, and they had slotted round heads rather than Phillips heads -- but they'd do the job. Today, when I finished the parts, I got the serrated washers that fit the bolts, and dug through the tray of nuts. Uh-oh. These are 10-24 thread, and I don't have the 10-24 nuts. That means it's time for a trip to Home Depot to get them.

Maybe it's even a good reason to go on a field trip to Park Center Hardware in Riviera Beach, a sort of mini-Heaven for those of us who spend way too much time in our shops (and I guess I qualify -- I was once told the perfect home for me would be a four-car garage with attached house.)

If you're in the West Palm Beach area, Park Center Hardware is in the Sav-A-Lot complex, a block north of Blue Heron on Broadway (Dixie Highway). The address (a new location for them) is 80 East 30th Street, Riviera Beach, FL 33404. The place feels like the other end of the world from Home Depot. It's an old-style hardware store, and it's been run by the same person for 35 years. Every single person who's waited on me is a character in one way or another. I enjoy going there, and I recommend it if you're in the area.

If you're in the Mid-Michigan area, another fantastic hardware store is Casler Hardware. This is truly an old-time hardware store, with the wooden floors and the classic old-hardware-store aromas. It's at 125 N Jackson St, Jackson, MI 49201. They dispense hardware and advice and a good, friendly, small-town feel.

I'll pick up the fasteners tonight.

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Assembling the Prototype

Okay, no field trip to Park Center Hardware. I was in a hurry, and the sky was looking like a major rain was rolling in from the southwest. I just stopped at our close-by Home Depot and grabbed the 10-24 nuts I need, and I got some 10-24 wing nuts for temporary use. The wing nuts will likely make it easier to get the head unit locked into its the semi-permanent position. I'd say "permanent position", but I know a carPC installation isn't really ever finished.

I haven't found mini-carriage bolts like I'd prefer to use. I have one I picked up somewhere, probably when I was disassembling a piece of equipment, but that's the only one I've found. I'm a fastener packrat; I don't pitch them into the metal recycling unless I have plenty on hand.

Here are the assembled parts from the front and rear, and then a shot with the head unit mounted on them:

Click images to enlarge.

You can see that the center flange is missing from the base. It cracked when I made the original tight bend on it, and it finally broke right off while I was test fitting. It's no problem; the final part will have a rounded bend there, and that won't crack.

If you enlarge the middle picture, you can see how the slots work. Unfortunately, you can also see that I really screwed up one of the base-unit slots by drilling holes that were too large (it was late and I was pretty tired; when I saw what I'd done, I quit for the night and started again in the morning). The good part of this error is that it shows how forgiving slots are; even with a wobbly slot or an oversize slot, the parts lock together well. They'll be more accurate in the final product, I promise.

Now for a test fit.

Test Fitting the Prototype

This fit in pretty nicely, but it's tight on the bottom where the fasteners slide against the bay walls.

Click image to enlarge.

I think removing the serrated-tooth locking washers on the outsides will make this easier; there's a good bit of thickness there. There will still be similar washers on the insides by the nuts, so vibration loosening shouldn't be a problem. I'd probably be wise to align the slots in the fasteners horizontally, so they just slide along the plastic walls instead of digging in. Both moves should help make this more of a slip-in fit than a push fit.

With the back flange missing, the pressure against the sides forces the bottom to bow right down and match the curved bottom of the bay. When I think about it, that may be just fine; it spreads the weight of the head unit over a greater area. Because of this, it looks like that back flange in the center will be unnecessary, and that saves a manufacturing step.

If you look above the head unit, you can see there's quite a bit of space there. Mounting the DVD in that location -- rather than underneath the head unit -- will keep it out of the way of the shifter, so I can use either a slot-load or tray-load unit.

That DVD mount is next.