Scion xB '06, in-dash Atom 330, Lilliput 889GL; details, pictures, links. Index: pg 1 - Page 8

rdholtz · 05-18-2008, 01:07 PM

Almost Done

Before getting the deck mounted, I wanted to finish the tabs that hold the head unit onto the deck, because I finally remembered to buy 6-32 speednuts at Home Depot. I slipped the speednuts onto the deck tabs and filed away a bit of the speednut corner to make it conform to shape of the deck tab. I marked the hole locations through the speednuts, and drilled 5/32" holes. I slid the head unit and bracket back onto the deck, marked through the deck tab holes to the bracket tabs, and took the bracket tabs off and drilled them the same size. I assembled everything with the tab brackets just a bit loose, and made sure there was a gap of 1/32" or so -- less than 1mm -- between the bracket tabs and the speednuts, and then tightened the brackets down.

Here's how it looks from the bottom with the head unit fastened to the deck:

Click images to enlarge.

Dimple Laboratory

Next it was time to fasten the deck to the support arms. I marked for fastener locations on the support arms -- centered on the arms, 1" and 4" back from the front of the deck, and drilled 5/32" holes there. I put the deck where it would go, and marked through the support arm holes to the deck, measured the locations to be sure they made sense, and drilled 1/8" holes in the deck.

Because I needed to keep the deck surface completely smooth, I wanted to use 6-32 x 1/2" countersunk-head machine screws and nuts to attach it; I didn't need the extra length, but it's easier to work with them in a cramped area when they're a little longer. The machine screws make it easily removable. Then I had a problem: I don't have dimple dies to make the dimples in the sheet metal that would allow me to use countersunk fasteners. Time to get creative.

I know that dimple dies just squeeze the area around a hole and stretch it downward. How could I do that? Let's see -- what if I took a fastener that had the right size head -- or maybe slightly larger -- and used it for the male die? I knew the hole in the sheet metal was going to grow as the metal stretched downward, so I needed to make allowance for that. I had to start with a smaller hole, which meant I needed a smaller shaft on the die. I found a countersunk-head screw with a big head and a smaller-than 6-32 thread, and that became the male die.

Then, for the female die, I needed to make a countersunk dimple in something. It had to be larger than the matching male die to account for the sheet metal squeezed between them. I thought of using a piece of wood. Could I just whack a larger fastener into a piece of plywood, or, better yet, particleboard, which is somewhat harder than plywood? Some experimenting on scrap showed that I could do that, but it's very imprecise: I couldn't get consistent results, and the scrap sheet metal parts ended up bent in ways they weren't supposed to bend.

Okay, how about steel? Angle irons and hinges have countersunk holes. How would they be? After some more experimenting, the answer turned out to be "only okay, at best," since I didn't have the size hole I really needed. So I got a piece of steel, drilled the right size hole, and chamfered it to the right size with the end of a drill bit. Result: one female die.

Some good ol' shop violence -- with a hammer -- produced good results on some test pieces, so I made the countersunk holes in the deck the same way. Sure enough, the 1/8" holes grew enough to work fine with the 6-32 screws.

Here are the countersunk holes in the deck:

Click images to enlarge.

I drilled the support arm holes out to 5/16", which was just large enough to allow the countersunk metal from the deck to nestle into the holes. I put the arms on with the 6-32 x 1/2" machine screws, fastening each with an external-tooth serrated washer, a flat washer, and a 6-32 nut. The deck metal actually protrudes through the support arms a little, and the serrated washer grips well while it fills the gap. I tightened 'em up, and the deck was attached.

Final assembly and a photo shoot, coming up as soon as the camera is charged.

lostreception · 05-19-2008, 08:33 PM

wow lotsa work going on here i wish it were easy even witht he detailed instustions o dont think id be able to recreate what youve done but if you have free time and want to imrove even more on you design id love to see the prototypes. can wait to see it in place

rdholtz · 05-20-2008, 06:03 AM

Quote: Originally Posted by lostreception

wow lotsa work going on here i wish it were easy even witht he detailed instustions o dont think id be able to recreate what youve done but if you have free time and want to imrove even more on you design id love to see the prototypes. can wait to see it in place

Well, it's in place -- I'll be writing up the worklog tonight. After all the design work, cardboard parts, prototypes, and final parts, plus all the stuff that just didn't work and had to be revised and re-revised, it's done. It's kind of sad that not a bit of the work shows. Installed, it looks like it belongs there: OEM.

I should have the log and pictures up tonight or tomorrow, depending on my work schedule.

Quote: Originally Posted by lostreception

i'd love to see the prototypes.

The prototypes are nothing to look at, really -- just what you see in the pictures. The steel is so light that they aren't strong enough to carry the head unit load in operation, and so they're only for positioning. The deck, head unit brackets and left arm never even got prototyped; they just went from cardboard to steel. The right leg prototypes are interesting to look at, but they don't fit as well as the steel final leg because I did the post-prototype refinement in the cardboard re-re-revision.

Now that I have a design that works, a good sheet metal guy should be able to crank these parts out pretty readily. I would recommend that the legs should be made just a bit shorter; that would allow for shimming in other cars, since units even of the same car are slightly different.

If I were to do a second version, I'd change the deck to allow a slot-load DVD player to mount below the head unit. But that's another development process . . .

I don't think a production version will be in the works; the first version of the Scion xB is no longer manufactured, and this wouldn't fit anything else. With all the parts involved -- deck, two brackets, two support arms, and fasteners -- it wouldn't be a cheap kit, and risking a production run on an unknown market probably isn't very wise.

rdholtz · 05-21-2008, 04:46 AM

Assembled Support System

I reinstalled everything in the car and confirmed proper fit, then pulled it all back out and riveted the right support leg. Before I forgot, I traced the leg for future reference. Here's the final leg:

Click images to enlarge.

Then, just to give an idea of what the whole thing looks like, I assembled all the parts I'd made. Here's how the completed assembly looks out of the car. It's upside down in these shots, from the left and the right:

. . . and here it is from the front (upside down again) and the top:

Then I fastened the head unit into its new home. Here it is, from the right and left sides (still upside down):

Click images to enlarge.

. . . and from the front and back:

She goes into the car permanently, next.

rdholtz · 05-21-2008, 10:25 PM

Permanent Installation

The support assembly couldn't be installed as you see it in the post above; it had to be disassembled and then reassembled in the car. I got the left and right legs in, and then put the deck on them.

Attaching the deck was a trick. One thing I'd change about the deck-to-support fasteners: next time I'd use locking insert nuts with plain washers (I didn't have the locking nuts in my shop, so I went with what I had). The combination of three pieces -- serrated washer, flat washer and nut -- was tough to line up in position in the tiny space available, and just two pieces would probably be somewhat easier. It would be nice to just use the nut alone, but something has to take up the additional thickness -- the nut alone wouldn't fill that gap.

Because of the fastener issue, the final installation was more time-consuming than would be acceptable in a factory situation, but for custom work, it's okay. I got it all installed and checked for fit one last time. Phase 8 was relocation of the head unit, so Phase 8 is Completed.

Here's how the head unit looks in its new home:

Click image to enlarge.

You can see that the dash is stripped back to bare bones. Underneath the head unit, the cigarette lighter and the passenger airbag indicator are functional, but just hanging around, right now. I expect to make a simple plastic insert to fill the area around the head unit, one that will provide a place to mount the both the lighter and airbag indicator, and perhaps a USB plug or two. It will clip in separately from the bezel, much like the OEM Scion cubbyhole unit did. ***Edit: If I can find a spare Scion cubbyhole unit, I'll use parts of it, especially the framework with the clips that plug into the dash, and maybe even the face part that holds the lighter. ***

Connections

This new support system is set up so the head unit can go in and out with just two screws, so pulling the head unit out to make the wiring connections should be pretty easy. Before I can make those connections, though, I need to extend the head unit wiring from the old location down to this new one. That's next.

rdholtz · 05-23-2008, 02:43 AM

Notes About This Part of the Project

Precision
One thing I noticed when I locked down the final position of the right support leg panels: I could have skipped the slots and just riveted the panels together. The front edge lined up precisely, and the top was exactly where it would have been if I'd matched the prototype. That tells me three things: (1) my prototyping was right on, (2) I fabricated the sheet metal parts exactly to plan, and (3) I was really lucky.

Because I'm new to sheet metal fabrication, I tried to design in as much wiggle room as possible, and I practiced on scrap to get the bending techniques down. I took my time, and was careful to hit the right measurements with my bends. I missed a few times, and ended up building new parts.

Sheet Metal Beauty
I made several comments as I was building this support leg that that the preliminary parts were ugly, and that I hoped the final product wouldn't be. Here's the progression: first prototype, second prototype, and the final product:

Click images to enlarge.

My verdict is that it got much better-looking, maybe even graceful, in the final product. Funny thing is, this is the only place it will ever be seen. Now that it's installed, it will be forever hidden from view.

Still, I like all the final parts I make to look good, even on close inspection, because that attention to detail leads me to produce better products, even ones that won't ever be seen again. And one other thing: sheet metal parts can have lots of sharp edges. I wasn't as careful about appearance on the prototype parts, but I still filed off the sharp edges and slivers. By filing every part before I used it, I only made a blood sacrifice once, when I slipped up handling a prototype piece as I was filing it. For a sheet metal noob, that didn't seem too bad.

rdholtz · 05-23-2008, 07:54 PM

Memorial Day

This is Memorial Day weekend in the United States. While it's a three-day weekend and a time to party for many, it's also a time to honor those who gave their lives in the cause of liberty.

For those who gave all, I stand in silent salute. Thank you.

To my fellow veterans . . . to my fellow combat veterans . . . to all those serving now . . . thank you. I salute you, too.

rdholtz · 05-24-2008, 09:07 PM

Machines That Would Have Made This Easier

If I had a metalworking shop, I'd have a bending brake that would allow me to produce a bend across only part of a surface. That ability would have completely eliminated the need for two separate panels on the right support leg; I'd have built the arm right into the panel. Then it would be a one-piece solution just like what could be stamped out in a manufacturing plant. It's an example of what Turbocad6 talked about back in post 103: "the right machinery can pump out many of the same pieces over & over each minute if it was a production piece." I don't have that machinery, and this single piece took eleven part-time days and several versions from concept to completion. Still, I have an insignificant investment compared to the cost of a stamping plant.

To cut the parts, I used tin snips on the lighter metal and a band saw on the heavier steel. The only flanging device I have is a 30" bending brake that I found in a garage sale for 20 bucks. It had never been out of the box, and originally came from Harbor Freight, where it costs $70. It doesn't include a clamping system, so I use my own C-clamps. It looks like this:

One machine that would pretty much have eliminated using those tools, and would have made this entire project a lot easier, is Harbor Freight's metalworking do-it-all machine, a 30" Capacity Shear, Press Brake and Slip Roll, for $400:

***EDIT (2008-06-09): Northern Tool also carries a 30" Capacity Shear, Press Brake and Slip Roll, and it looks very much like the Harbor Freight unit. I'll compare before I buy.

Such a one-machine metal shop would have eliminated most of the filing to get surfaces straight after cutting them on the band saw; they'd just need the sharp edge knocked off, and they'd be ready to go. This machine is also available in 40" and 52" models for even bigger jobs. (If you have an extra one, or something like it, I gleefully accept donations, and can pick up anywhere between the Florida Keys and the Atlanta area.)

For that kind of donation, I'd even make you a whole set of these parts, but I don't think I'd want to go into production on the very basic devices I have now.

I can also see that I need to add a larger, more powerful grinder to my shop, perhaps one with a buffing wheel.

Over the long haul, I'd like to add a small milling machine. For right now, I'd just like an easier way to make slots in sheet metal. Maybe a drill press milling vise on a second, smaller drill press I have would be an answer for making slots; it would probably be pretty hard on the bearings of the drill press, but it might be okay for occasional use until I can justify a mill.

***EDIT (2008-06-09): If I were going to try and justify a mill, the Northern Tool Mill/Drill/Lathe Combo machine seems like a pretty good choice for the sort of work I do:

It's $700. The good news is that I can order it shipped a store for free, instead of paying well over $200 shipping, so it would be worth it to pop the trailer on my Scion and make a 145-mile round trip to Miami to pick it up.

(Yes, I do tow a trailer with the Scion, sometimes. It tows just fine. The Scion is an amazingly capable vehicle.)

rdholtz · 05-26-2008, 10:07 AM

Extending the Head Unit Wiring

The final part of moving the head unit was to extend the audio cables and the antenna. I'd already picked up an extension cable for the antenna at the local auto parts store. To extend the power and speaker wires there are kits that work for some of the cables, but I wasn't able to find a kit for the steering wheel controls.

Metra Parts 70-1761 and 71-1761 -- available here for as little as $21 with shipping -- would make plug-compatible extensions for the power and speaker looms if I soldered the individual wires together. The wires on the parts are over 6" long, so the resulting cables would have been 12" or so, and that was good for this application.

Here are the Metra kits:

Unfortunately, Metra doesn't make the steering wheel control wire kits. I was told by one tech-type that I could use 18-gauge speaker wire and put those eight wire extensions in myself. That's probably overkill; the factory looms appear to be mostly 20-gauge or 22-gauge wire; a few were even 24-gauge.

I noticed something interesting. Three of the wires arrive together and, about 3" from the fitting, split up. They're black, white and a bare ground with a shield that wraps them until they split. I suspected these were the power and ground wires for the steering wheel controls, shielded to keep from messing with data signals in the other wires. I decided I'd better shield them in the extension, too. I used stranded, bare-ground 20-2 shielded wire for those, and stranded 20-gauge wire for the rest.

I started the job at my workbench by cutting 24" of the shielded wire and five 13"-long 20-gauge extension wires. I put two pieces of shrink tubing on each extension, then stripped 1/2" at each end.

I ran the three extensions with shielding first. I trimmed the three wires to the right length, leaving plenty of shielding extra. After soldering them and putting on the shrink tubing, I shielded the entire joint area by wrapping it in the extra shield material, and I covered the whole joint with black electrical tape to hold the shielding in place.

Then I did the other five wires: cut a wire, strip the cut ends, put in the extension, twist the wires together, then move to the next wire. By doing each wire individually, I made sure not to cross any of the connections. After I did all five wires, I soldered all the joints, folded them down, pulled the shrink tubing over them, and shrank the tubing with heat. I wrapped the whole loom of eight wires in black tape, just like OEM. The end sticking out of the black wrap looks absolutely stock.

The only problem I ran into is that my little butane soldering torch stopped working just before the last of the soldering, and I couldn't seem to get it to go again.

I resorted to an old electric soldering iron which, after I used emery cloth to get the tip to fresh copper, worked just great.

The work was more tedious than difficult. Just to be sure I'd done everything right, I plugged in the head unit and added power. It worked fine.

Since I'd already had to extend the eight steering wheel control wires, I'd been through the ugly part of the learning curve. I decided to just do the other 14 wires -- for power and speakers -- the same way. But I hated all that time cooped up in the passenger seat, so I took advantage of the color coding on the wires and just cut all the wires about 3" from the plugs. I made the extensions wires of different gauges, depending on what was in the original harnesses, soldered all the extensions to the plugs at the workbench, and shrank on the shrink tubing. Then I climbed back into the car to make the other half of the joints, and just took extra time to check that I got the wires connected right.

Payoff: in the last check before installation, I plugged in the cables, added power, and had tunes. I ran through the fade and balance settings to be sure all the speakers worked, and everything worked fine.

Yeeeee-hawwww!

Then came the most painful part of this whole exercise: getting the wires through the tight spaces available behind the dash to their new home -- a place they were not designed to go. I didn't know my hands and forearms could twist like that -- maybe I should go for a job as a contortionist. Finally, after finding out I'm more flexible than I thought, and after leaving a little skin inside the dash, I got the new longer cables and the antenna extension run. I put the head unit in its new home, wiggled the extra length of the cables back into the dash as I slid it in, and screwed it down tight.

Here she is in action, this time with the original bezel around it so you can see where the small plastic face will have to be:

Click images to enlarge.

That plastic face will fill the gaps on the sides and top, and, as I mentioned earlier, provide the mounting point for the cigarette lighter plug, the passenger airbag indicator, and USB plugs.

After all this time without music in the car, it's good to have it again.

***Edit: In the picture above, the colors of the head unit and the face above it are actually closer than the image shows. The head unit is black and smooth, so it absorbs most of the light and reflects only a little of it. The control surface above it is dark charcoal gray and textured, so it diffuses the light and it appears in the camera image to be much lighter than it appears to the eye.***

rdholtz · 05-27-2008, 08:09 AM

Would I Do a Production Version of This?

With the design work completed, producing these parts is a straightforward process, except for the right support leg. That throws a wrench in the works; it's a real pain in the behinder because of the accuracy required by the long cantilever.

I commented earlier that I didn't think a version of this could be produced economically, but I've still been considering how to redesign the parts so they'd be easier for others to make, or for me to make again. A production version would need adjustability to account for the variances among cars. I think I would add slotted adjustments, just as the OEMs do (that's how fender washers came into use -- great big washers with small holes that give assembly workers lots of room for adjustments). I would probably slot the left leg fastener opening (post #99) for height adjustment. I might keep the right leg (posts #105 & 109) as two slotted parts, with two or three slot sets to tighten down after positioning.

As I mentioned before, the deck-to-support-leg fasteners weren't very easy to get into place (post #110), so I'd want to revise that, too, maybe even using rivnuts or nutplates. I might also consider indenting those two strips where the deck bolts to the legs; that could eliminate the countersinks (post #106) and make it easy to use slots.

I would definitely change the head unit mounting brackets (post #91). In the revision, I'd combine the brackets and the mounting tab plates, I'd shorten the brackets so they mounted only to the lower two bolts on the sides of the head unit, and I'd add horizontal slots to their mounting holes. That would make it so the deck could be adjusted for depth relative to the dash, and that flexibility would make it much easier to fit the bezel. The shorter brackets would improve cooling because they'd allow more airflow.

All those ideas might be good if I just went with the unit I developed in this process. But, realistically, they amount to redesigning every part of the existing unit. The HU brackets would be simpler, and the legs and deck would get even more complex. More complexity isn't necessarily a good thing. This system is already tedious to make.

But going through this reconsideration exercise has gotten me to thinking that maybe there's a better way to do this -- faster and much, much easier. Hmmmm -- the sketchpad calls. Stay tuned; I'll be back tomorrow after I noodle this out.

rdholtz · 05-28-2008, 08:47 AM

What If I Just Started Over?

Okay, I've reviewed the approach I took to mounting the head unit, and the reasons I took that approach. I originally felt that it would simply be bad practice to mount anything to plastic with no fasteners going into metal. But, while I did the design and redesign work on this project, I've looked at the dash from different angles and gotten a lot of hands-on experience with it. I recognize now that the inner walls and floor of the cubbyhole bay are surprisingly stout, even though they're plastic.They appear to be well supported by the minimal steel structures in the dash.

If I were to do this over, I wouldn't go through all the complexities of the long right leg and short left leg. I'd seriously consider mounting a sheet metal support deck directly to the plastic inner walls and floor of the cubbyhole bay. I'd match its bends exactly to the contours of the bay; that means it would taper to the rear and have a couple of bends on each side, but it could easily be manufactured in my bender.

The deck could be attached using small bolts that run through the plastic walls. I thought about using fastener plates behind them, because that would spread the loads pretty well, but there's very little load on the fasteners. I think short sheet metal screws that run through the walls would be enough -- they're needed only to hold the deck in position, not for support; there's little likelihood of tear-out because the deck itself would spread the loads widely.

I'd make head unit brackets that attach the head unit to the deck plate; they'd be slotted vertically so the head unit position could be adjusted up and down, and slotted where they attach to the deck plate so the head unit could be adjusted in and out. It might even allow for a little tilting if the installer chose to do it.

I noted what could have been a stumbling block at first: the bends need larger radii than my bender produces, to fit the shape of the plastic. But that can be taken care of by using a bending block with a larger radius, so there's no issue other than getting some practice with how that different block would affect the bends.

This completely different head unit mounting system would be far easier to install and far more adjustable, and it would still be removable. And, even more interesting, it could be much more easily duplicated: three simple parts and some fasteners. It would take longer to extend the head unit wires than to install the mounting system.

Ah, isn't hindsight wonderful?

There's an unknown in that new design: I haven't actually built such a system, so I don't know absolutely that it would work, but I'm pretty confident.

The system I did build is in place, and it's solid, so I'll keep it for now. Building it helped me learn more about sheet metal design and fabrication, and I successfully solved a tough and interesting problem. Good use of my time.

But I think I'll do it differently next time . . . and next time may be coming up on Ozzy71's xB. We'll figure out if we're doing that project this week.

I know this design is primarily of interest to xB owners, but maybe it points the way for owners of other cars, too. I think the project is worthwhile enough that I may take my head unit mounting system out and see if I can produce the new style, just because it sounds interesting.

rdholtz · 05-29-2008, 09:09 AM

Head Unit Support, Version 2

This support is basically a big U-shaped piece of sheet metal with some extra bends, and a couple of wide L-brackets bolted to the bottom of it. The head unit will ride between the brackets.

I haven't taken the "old" head unit support system out of my car -- yet. I'm off to Atlanta for the better part of a week (without the car), so I'll leave it as-is until I get back. But I grabbed a flashlight and began to recon the cubbyhole bay, and I notice some interesting things as I prepare to develop this simplified support:

the floor of the cubbyhole area only goes back part of the way (and then there's just open space), but the upper walls are full depth. There's still enough deck space for mounting the brackets, because the OEM mounting bolts that go into the sides of the HU are close to the front of it.
there's a cable -- for the cigarette lighter -- that comes up through a hole in the floor of the bay; I'll have to move and possibly extend it, depending on where I want the lighter assembly to mount. I'll keep the lighter in the car for auxiliary power.
the walls of the mounting area taper inward as they go back; it isn't going to change the way the mount works, but it will make the layout on the raw material a little more challenging.
in the left side of the back, close to the bottom, there's an unused fastening point on a dash support bar where the deck could be attached to steel for stability. It's right below the point where I mounted the left support leg in the previous version.

Here's a look into the bay, with a finger pointing to that fastening point:

Click image to enlarge.

The more I think about this support, the more I think very little -- other than the weight of the head unit -- will be required to hold it in place. It will be locked in place laterally by the walls and vertically between the floor and top of the bay. No significant forward-backward force will ever be exerted on it, and If I add a tab at the back for that fastening point, perhaps the entire system can be held in just by a single bolt through that tab and into the dash support bar. That would hit the installer's ideal: no drilling required to install it. I'll have to get the deck plate angles and the side heights just right.

The challenge is going to be designing the slotted attachment between the deck and the support brackets. I want the bottom absolutely flat, to spread the load out over as wide an area as possible. I need a fastening system that doesn't interfere with that. Hmmmm.

Everything else looks to be pretty simple. I'll be peering into Ozzy71's car tonight, since his cubbyhole bay is vacant. I'll do a cardboard mockup and see if this is really as simple as I hope it can be.

rdholtz · 06-01-2008, 05:03 PM

More on the Head Unit Support, Version 2

Since there are already large open areas in the floor of the cubbyhole bay, I may be able to take advantage of them. The area on the right side of the floor means there will be no issue with bracket fasteners that protrude through the deck floor. On the left side, there won't be a problem with the rear fastener protruding. That leaves only one fastening issue to resolve: the left front. So the logical question is: do I need it? What if I built the HU bracket as a U instead of two separate brackets? That would mean three well-spaced fasteners should be enough to hold it solidly in position. Once again, I think carriage bolts and wingnuts will do a fine job. The only problem there is figuring out how to get my round bits to drill square holes.

Another potential issue would be the need to hold the top of the deck system against the side walls. That could be eliminated by adding a fourth side -- a ceiling -- to the deck system. Then the whole unit could just slide into place and be attached by the rear tab. It might even be a very good place to mount a thinline DVD support. Oh, this is sounding better and better.

If the floor of the support unit isn't strong enough -- if it flexes as the head unt weight is added -- I can double the thickness, but that scenario seems unlikely; I bring it up as an issue that's easily solved if it arises. To double the floor, I'd add material to the front and bend it up and in. Another approach -- probably the easier one -- would be to put flanges at both the front and rear of the floor.

-----

All it takes to pull the Scion dash apart is a flat blade screwdriver for prying and a Phillips screwdriver for the fasteners. When I finally tore into Ozzy71's dash, I ran into a roadblock. I forgot that we'd already modified his dash to build the support for the external 15" monitor, so I had to do some additional disassembly that took tools beyond the screwdrivers I had with me. Here's the way his looks:

Click images to enlarge.

The rivets in the upper part of the back wall hold nutplates I installed to provide strength so we could fasten the back plate of his screen mount to this plastic dash (and they worked great until thieves broke into the car and stole the screen; fortunately, they were in a hurry or stupid -- probably both -- and only took the touchscreen and the custom mount, but left the computer; they didn't damage the dash). The pictures show the layout of the area where the head unit will live. You might also note that many of the wires in the image are not OEM; they're wires we added for power, data interface, touchscreen interface and sound for the now-missing screen.

Once I got into the dash, I took an hour or so and built a cardboard mockup of the way the deck unit will work. That helps me decide how and if this can be done, and how easily, and it tells me what obstacles I need to beat. In this case, there are a few, but all appear to be pretty easily overcome:

The sides change shape a lot; that'll just test my bending skills.
There are some protrusions at the bottom, and a cable in the way; I'll form the back of the bottom with a flange in front of them to add strength and eliminate any interference.
The floor area is not directly beneath the area where the head unit fasteners will be; I'll have to make a little zigzag in the brackets. That will be easier to visualize in the mockup.

The next trick -- one I'll save for when I get back to Florida -- will be to duplicate the cardboard mockup in light sheet metal and see if it's pretty close. I'll refine the result and then make a first attempt at a 22-gauge steel system. Once I have the exterior shape done, I can configure the U-shaped bracket to hold the head unit, and another shallow U to encase the DVD.

rdholtz · 06-03-2008, 07:45 AM

Even More on the Head Unit Support, Version 2

I've looked at this new design critically for a couple of days, now, and wondered if I've gone overboard. I wanted to spread the loads as widely as possible, and I wanted to avoid fastening into plastic, so I thought it would be wise do some extra work to be sure I don't have a failure later. The design followed all the contours of the bay's sides and went all the way to the top.

Here are those pictures of the bay again, for reference:

Click images to enlarge.

I wonder now if maybe this fancy metal-bending exercise is overkill. I could use a simple U of steel with a 7"-wide bottom and 3" sides that come up and bend onto the lower angled surface of the bay. That would require just two parallel bends on each side. I could still fasten it to that mount point in the back of the opening. Although I could add some sheet metal screws that lock it into the sides of the bay, that would likely be unnecessary because the head unit bracket will lock it against the side walls.

The full-height version doesn't seem to add much support, but does add significant complexity. Although it might be a nice challenge to get the relatively complex form bent, I like simplicity if it works as well, so I'll start with the shorter design and see how well it does what I need.

This shorter design will mean working with a single piece of sheet metal that starts out roughly 13" wide and 6" deep. If the double-thickness bottom is necessary, it will add a few inches to the depth.

Thinline Laptop DVD Drive

A separate DVD support can be added by attaching a top to the HU bracket. If I want to adjust for height, I could use slotted fasteners, or just rivets if no height adjustment is necessary.

One interesting thing I discovered in looking at a number of laptop DVD drives is that many of them seem to have two small threaded holes in the back face, a perfect place to fasten a keeper bracket. That resolves the concerns I had about DVD unit positioning and retention. A U-shaped bracket the same height and width as the drive would contain it laterally and vertically, and the rear keeper bracket would maintain its depth in the dash. The keeper bracket could attach to slotted holes to allow adjustment for depth in the dash.

Actually, as light as these DVD drives are, they could probably be attached with some high-quality hook-and-loop (Velcro-type) strips, but I'll go with the more traditional steel.

Creative0Mind · 06-03-2008, 01:47 PM

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