Head Unit Brackets
The head unit brackets were going to have mounting tabs that match the deck tabs. But, to be honest, I forgot to include them in the drawing, so I forgot to include them in the metal parts. Instead of making another set of brackets with the tabs, I made add-on tabs that make up for the omission; they bolt right on top of the brackets. I went directly to heavier material for the brackets and tab plates, but these are made from the the web of a galvanized steel stud drywall track. I'd been experimenting with this material and, although it's a relatively light gauge, this seemed like a good application for it. Here are the original cardboard brackets, the metal brackets, and the extra tab plates.
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Click images to enlarge.
Here's the head unit with the brackets and tabs bolted on, then the deck started into position, and finally the complete assembly (the deck is inverted in these photos).
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I still need to drill the holes in the tabs so I can fasten the HU in place, but I'll wait to do that until I get the speednuts. Putting the extra material (the speednuts) between the tabs will mean a little readjustment, but that will be easy. With the holes in the brackets somewhat larger than a simple clearance fit -- they're 1/4", like the holes in the OEM brackets -- there's a lot of adjustment room. I can move the parts around until the fit is exactly what I want, then tighten the bracket screws down and slip the deck back out, ready for more work on that part.
Because the deck plate has to slip into a relatively tight opening between the head unit and the brackets, I did an assembly-easing trick to the brackets' bottom flanges: I used wide pliers to bend about 1/8" of the rear ends down just a bit so the parts will slide together easily during installation. You can see those slight bends in the bracket photo and in all three of the assembly pictures, but you'll probably have to look at the enlarged view.
I have a little final cleanup work to do on the cooling hole; I'll do that when I'm filing away on the next parts.
This portion of the project has really worked out well. I'm happy with the way the parts fit and feel and look.
Next I'll go to the light sheet metal to make the left leg, the deck support strengthening flanges, and the right leg. Then I start the hardest part: making it all fit in the proper alignment. That's where the inherent inaccuracy in cardboard really shows, and it will take a lot of fit checks as I build parts. Once it all aligns perfectly, I'll make the parts in the heavier steel and do the final assembly.
Very well organized worklog, nice setup, keep up the good work.
Thanks, Almera. This is fun, and I appreciate the props.
Originally Posted by almera
when u get your prototype done let me know as id be interested in buying a bracket to relocate the HU your work is very good keep it up
I hadn't thought about going into production on these. Maybe a kit would be interesting. Hmmm . . .
Originally Posted by lostreception
Let's wait 'til I get done with this to see if it's something that could be produced easily, or if it would simply be too expensive in production time to be reasonably priced.
nice documentation of the project & the thought processes behind it. I did notice mention of concern with a PC DVD drive drawer & interfering with the shifter, have you considered a slot load? the slot loads can go in places you wouldn't normally consider a drive... even if it's not up front & center, the convenience of having it for even the one or 2 times you may actually use it may be worth the consideration...
I agree, a slot-load is a good idea -- that's what's in the existing head unit, and I like it. Since I already have a slimline tray load DVD unit, I wanted to avoid buying a whole new drive for a small convenience. I'd decided to stick with what I have and just add a slimline case.
Originally Posted by turbocad6
When I first considered this, I thought the DVD could live in the glovebox and use a Firewire connection (meaning I'd have to add Firewire to the PC). Now I'm wondering if I could mount it externally on top of the PC case and use the slimline-to-IDE converter I have.
Still, there's plenty of room for a slot-load below the head unit. I could easily fabricate a mount. And it would be very, very handy. Hmmmm . . .
Right Support Leg
This piece turned out to be a classic case of designing something I couldn't build, at least not in my shop, or at least not in one piece. Sometimes it's a long way from theory to reality. In this case, it's a long way from cardboard to sheet metal.
Actually, what this part shows is the limitations of my shop. Compared to the way Original Equipment Manufacturers would produce this part, I use relatively primitive methods: OEMs are automated, while I do everything by hand; they use gigantic machines and a series of dies, while I use small machines and hand tools; they do stamping and some finish work, while I do cutting, bending, drilling, grinding and filing; they do thousands of parts at a time, while I end up with one or two pieces.
But I do have the advantage of speed: they have to go through design, design review, approvals, change orders, tooling orders, setup times and production schedules; I can design, prototype and produce a finished product in a few hours.
Actually, I'm making an unfair comparison. I operate more like an OEM prototype shop -- sometimes known as a manufacturing model shop -- and the products from my shop are pretty similar to what a prototype shop produces: sample parts. If you ever get to watch a prototype-maker in action, it's an experience. The ones I've worked with were masters of their shops, and they quickly knew how to build stuff just looking at the sketches or drawings. The best one -- Frank Moses -- had experience on the manufacturing floor, and taught me to refine my designs so they're easier to make and lower in cost.
So how does all that apply to this support leg? Well, here's where I'd gotten: Version 4 of the basic shape, showing the fastening tabs at the bottom and the deck support arm at the top:
Click images to enlarge.
Version 4 was different from Version 3 because it has added width; I wanted all the strength I could get in this part. I thought I'd add flanges on the front and rear edges, and a doubler plate through the middle of the web to make up for the narrowed area (a doubler is essentially an extra layer of steel; it makes the part thicker and stronger).
Then I took off my designer hat and put on my prototyper hat. It didn't take me long to realize that I couldn't build it in my shop unless I wanted to beat it into shape with a hammer. :) I couldn't use my bender to make the front flange (on the left in the photo) because it won't bend just part of a surface; it would bend the arm, too. I couldn't bend the separate back flanges, either, because they're not in a straight line.
Decision time: get bigger, better equipment, or do yet another redesign. Since redesign is an immediate-results, no-cost option, that's what I chose. As it turns out, Version 5 made it much easier to get the whole mechanism aligned.
I had to figure out how to get a part that would fit and still be strong. At its narrowest point, the part is 2" wide. It can't get any wider at that point because it squeezes between the dash and the HVAC system. With that limitation, and with the limitations of my shop in mind, I decided to produce a quickie prototype with 2" channel and add pieces onto it: a separate panel with feet, plus an upper angle arm to support the deck. All the parts were made of light-gauge galvanized steel.
I put the foot panel in place in the car and modified it -- bending, re-bending, nibbling bits away -- until I got it so the feet sat flat on the mounting points without fasteners. I marked for the mounting holes and drilled them (oversize), and bolted the foot panel into the car.
Then I put the main channel in, got the alignment between the channel and the foot panel figured out, and marked them. I took both parts out and riveted them together, and bolted the assembly into the car.
Finally, I put the support arm in place, put the new deck and the cardboard HU in, and marked on the parts where they should connect. Everything came back out and, after drilling holes for rivets to connect them, I got this configuration, seen from both sides:
Boy, that prototype is seriously ugly -- it looks like a stunted toucan. I can promise that the final part will be stronger and cleaner-looking. For now, it works, and I know the most important thing: that I have the final alignment pretty close.
I want to prototype the support arm and tab for the left side, so I can set the whole assembly in the car, put the real HU on it, and be sure it all works as expected. Then I'll refine the alignment, clean up the designs and build the final parts.
The prototype left side parts are next.
Left Support Leg Prototype
The whole head unit support assembly will have to make up for unfortunate engineering in the vehicle. While the dash is very strong, the HU is moving down into the lower area where there are only a few structural attachment points within reach; the dash is mostly plastic in this area. That means I need a very strong system that makes up for badly located mounting points. This left leg attaches at the back, with only one fastener, so it's cantilevered. I'll build the part in sheet metal, but I'll use a heavy steel lug -- actually a piece of steel plate cut to size -- under the fastener head to keep the part from bending.
Building the left leg was a test of my ability to envision a part, get an outline, and make a single piece of sheet metal into a 3-dimensional part. I knew pretty well what it had to be from my cardboard mockup, so I traced onto paper as much of the cardboard part as possible. Then I added pieces that would make it strong enough to hold the actual head unit, including the flange where the leg will attach to the deck, and a brace that would keep it from deforming under load.
To get it to fit correctly, I bent it, but didn't fasten it together. Once it was in place, I checked for fit and found that the angle was slightly off, and it sat too high (meaning the leg was too long). After trimming the brace twice, re-bending once, nibbling off some of the leg twice, and lots of fit checks, I got it to fit well. I fastened it together with a sheet metal screw and did a final fit check.
Here's the sketch, modified with the changes I made, and the prototype:
Click images to enlarge.
For size reference, the part is 5-3/4" long from the left end to the bend. The blade is 3/4" wide.
Final Left Support Leg
I decided there was no sense waiting to build the final part, so I modified the tracing based on the partially-unbent-and-flattened part, and built the final part in heavier aluminized steel. I used the heaviest sheet steel I had, because this part bears significant load. The trick was allowing for the additional thickness when I made the bends. After a couple of adjustments -- the leg was too long again, and I had to fine-tune the brace -- I got it just right and riveted it together. The back edge of the vertical brace sits firmly against the leg, strengthening it.
There was one change: in the final version, I placed the attachment panel on the outside of the vertical brace, simply because it was easier to put it there, rather than inside. It isn't quite as pretty, but it's a hidden part, so it'll be okay.
Here's the final part:
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I'd have preferred to have the vertical support arms come down both sides of the support, but it would have been very difficult to get a screwdriver onto the fastener when I installed it.
The last element of producing this part was to makee the steel lug. It's just a piece cut from a 3/4"-wide galvanized steel bracket. I used an existing hole in the material, so I didn't even have to drill it. The lug is there to spread the load of the large fastener head all the way up the bracket leg, so the cantilevered part won't bend under the rough-road loads it may get. Here's the bracket without the lug, then with both the lug and the OEM fastener:
You can see that the lug adds considerable thickness to the leg, and should make it stronger.
Now I'll go back and make sure everything is aligned well before I produce the final right leg.
Re-revised Right Support Leg Prototype
I discovered as I was installing this right leg that it can go in from the top instead of having to work it up from underneath the dash. That made things a little easier for all the fit checks. There were a lot for this prototype. It's almost a saga.
I had the new final version of the left side in, but a funny thing happened when I got the prototype right leg in the car with it: they didn't match. Fit checks showed that the left leg held the head unit deck exactly where I wanted it, but that I needed to readjust the right leg's deck support arm so the deck sat level. I also needed to make the front of the arm tapered like the left one, so it, too, was hidden behind the deck's front flange.
To start the rearrangement, I wanted to flip the deck support arm around so its flange pointed toward the outside, as it does on the left support arm. The vertical channel was just a bit too tall, so I cut the top back corner off it to avoid interference. Then I cut the support arm so its taper matched the left side, and started the re-fit. I made changes to both the height and deck angle. I modified, did a fit check, modified, did a fit check, etc., until I'd installed and uninstalled it several times, but I never got it so it fit just right.
I was really struggling to get this thing aligned in the tight space available, so I devised a quick workaround. I bolted two small Meccano angle brackets to the channel, using existing holes near the top, and ran a machine screw and double nut through each of them. That gave me two adjustment points so I could see where the deck support arm needed to be.
Here's the channel and feet with the adjustable positioning screws:
Click images to enlarge.
There was no attachment between the screws and the arm -- I just used them to position the height and angle of the support arm until I got it in just the right spot. Then I marked where it went, removed the temporary angles, and screwed it all together.
It still wasn't quite level with the left support arm. Grrrr . . . . . mutter, mutter, mutter.
Okay, if the easy workaround was unsuccessful, it was time for a different approach. I pulled the Meccano parts off. How about using slots for adjustment? That's what I did next.
I wanted a vertical slot in the channel and a horizontal slot in the arm. I cut the slots by drilling starting holes at each end, then putting a cut-off blade in the Ryobi rotary (Dremel-type) tool, and cutting out the metal between them. After filing them smooth, I fastened the parts together using a small carriage bolt and a wingnut. The carriage bolt has a small square area under the head (see the picture above) that doesn't let it turn in the slot, and the wingnut is easy to tighten by hand, so I could hold the channel and arm in position with one hand and tighten the fastener with the other. Serrated locking washers under the head and the wingnut kept them from slipping. (The serrated washer under the bolt head is a bit larger because the square under the head has to fit through it, where the other one just has to clear the threads.)
Here's how the parts looked:
The camera couldn't see the vertical slot very well, so I outlined it with a marker. You'll see that it ran into a previously-used hole; it's just a prototype, so I ignored that. I did have to make a new support arm, because I'd chopped the old one up so much I couldn't get a slot that would work. That was quick and easy, because it's made of the galvanized steel stud track material, and even has the bend already formed.
I got the assembly finger tight, but loose enough to let move it a little. I installed it in the car and made adjustments and measurements 'til it was perfect, then tightened the wing nut down tight. I marked the outline of the connection point on the parts -- just in case I bumped it out of position later -- and, at last, I had a finished prototype. :drum:
The slots worked great. Wish I'd gone down that path in the first place . . .
Here's the comparison -- the old prototype is on the left, and the new prototype is on the right:
Yep, it's still ugly. Perhaps not quite as ugly . . . and it works.
It's time to refine the design and see if I can get strength and beauty into it. Okay, maybe not beauty -- but at least I should be able to produce something that doesn't look like it was made in an 8th-grade shop class . . .
On a side note, that comment leaves me wondering if very many schools still have 8th-grade shop class. It was a long time ago for me, in Homewood, IL. Our shop teacher was Mr. Millush, and I think his primary lesson was to work without hurting ourselves. Safety was the focus; technique was secondary. Every time I use a knife, even all these years later, I can hear him saying, "Cut away from yourself!" And every time I go near a grinder, I can hear him saying, "Wear your goggles -- you only get one set of eyes. Replacements are not available." Good guy. And, apparently, a really effective teacher: I still have all ten fingers and both eyes.
Designing the new style prototype is next.