Monday, January 26, 2009

Lower Seat Reinforcement Preparation

About a thousand years ago there was a thing I used to do, it involved a car, a welder, and a dream-like delirium induced by blood loss and rust inhibitor fumes. Oh yeah! I was restoring a 1968 Ford Mustang convertible!

Well, I'm back at it and when I left off, I had welded a new floor into the beast. Part of my absence was due to cold weather but the real catalyst for procrastination was the prospect of grinding 200 welds. I finally suffered enough cabin fever that even weld-grinding seemed like fun so out I went into the cold, dark, confines of my little garage and set to work. I began by grinding the welds on the top side and then... well... more procrastination because the prospect of grinding the bottom of the floor was even less palatable than grinding the top since it involves me laying on my poorly functioning creeper. So, another two weeks of inactivity flew by before I was again bored enough to continue but continue I did... after I bought a new creeper from Harbor Freight with an adjustable head rest!

I started by grinding the main part of the welds down with my trusty 4.5" angle grinder with the edge of a grinding wheel. This shows the rough grind in comparison to the untouched welds. This is the grinding wheel used for the first step:

This is my alien disguise that I wear for Halloween and grinding welds. I always wear face shield, ear protection, and a respirator when grinding because even something as benign as grinding produces potentially harmful fumes. Not from the metal per-se but rather from the grinding disks themselves. Also, primers, sealers, etc that may be vaporized during grinding make me sneeze up some nasty stuff many hours after finishing work if I don't wear a respirator.

After I finish the first, rough grind, small holes were exposed where I didn't quite touch one side of the plug weld hole or a gas bubble had formed so I needed to touch up the welds. Again, I wear breathing protection. This particular mask contains charcoal filters and although it isn't as good as my primary respirator, it does an adequate job of filtering the smoke and vapors generated during welding and it fits under my welding helmet.

Next, I clean up the touch-up welds with a 24 grit flap disk wheel which also is aggressive enough to smooth out the grinding disk gouges.

And finally, I follow up with an 60 grid flap disk. This is as smooth as I bother to take the welds.

The finished product...

Followed up by a coat of primer. In this case, I only covered the exposed metal over which I intend to install the lower seat reinforcement pans since I intend to do a fairly extensive re-prime of all of the freshly-ground welds. This area, however, was going to be covered permanently when I weld in the new reinforcement panels so it needs to be protected now.
Finally, I'm ready to test fit the lower reinforcements. I placed each one in position individually and then bolted on the cross-tunnel plate an supported the back end with a floor jack. The front end is supported by a flange that tucks between the floor and the front floor support rail.

A close-up of where the reinforcment flange tucks under the front floor support rail. Note that the rear inch or so of the front floor supports have to be cut to be allowed to drop down under the reinforcement panel flange. This is much simpler to do BEFORE the floor is installed. I did this correctly on the passenger side but forgot to do the driver side so my reward was carefully cutting this flange laying on my back with the car's floor interferring with the angle grinder but I got 'er done.

After I had gotten the lower seat reinforcements fitted in their correct position, I was going through some old reference pictures I had taken just to make sure I had the cross-plate on correctly and discovered something was missing; the slots for the emergency brake lines! The e-brake cables are supposed to pass through the lower seat reinforcements. I was a little miffed because if I had gone ahead and welded in the reinforcements, I probably wouldn't have noticed the missing slots until the car was nearly reassembled and it came time to install the e-Brake cables!

I'm happy that I dodged that bullet though. I went out to my pile of rusty metal and recovered the old lower reinforcements. I had cut them up to remove them but enough was left to make measurements which I transferred to the new reinforcements.
I then used an angle grinder cutting disk, jig saw, and 1/2" drill to make the various slots.

Next, I re-fitted the lower seat reinforcements into position and soon decided that I didn't like using jack stands to support them so I stole an idea from another VMFer who was restoring another 68 convertible. He suggested I hold the lower reinforcments up using long bolts and fender washers (thanks yelostang!). Since I had no fender washers, I improvised by using 1/4" plastic plate that I had cut into 2"x2" squares with holes in the center. I think it's good because the plastic won't scratch the primer plus they can be tightened and yet still give when I smack the reinforcments with a dead-blow mallet for that oh-so-precise adjustment.

Here's a shot of the clamps from the bottom.

Having the reinforcements in position, I then used a white grease pen to mark the outside edge of the various flanges on both sides. I then marked reference points at either end of each flange offset 1/2" in to represent the center of the flange. Then I drilled 1/8" holes at each point.

Why did I drill 1/8" holes at the ends of each flange for the lower seat reinforcements? Because I'm lazy of course! I don't want to lay on my back to weld so I want to drill plug weld holes in the floor and weld down into the reinforcement flanges. But how do we know where to drill the plug weld holes? Well, I could just drill them all up from the bottom but see above statement regarding my lazyness. I want to drill the majority of plug weld holes down on the floor as well. So, the 1/8" holes were reference points between which Icould use a white grease pencil to draw reference lines which represent the approximate center of each of the lower reinforcement flanges.
Finally, I marked every 3 inches along the lines and drilled my obligatory 3/8" plug weld holes with my favorite Blair Premium Spot Weld Cutter (god, I love that thing).
Wow, this was a loooooong blog entry but that's what you get when I procrastinate and spread a relatively simple task over as long a period as I can. Next I need to weld in the reinforcements.

Saturday, January 10, 2009

My New Old Dash Clock (Repair)

It's been awhile since I last posted an entry. This is mostly because it's winter and I hate winter and would rather hibernate than doing anything productive. Sure, I've got loads of excuses such as "The house furnace is in the garage so I can't generate noxious fumes or I might kill the family", or "I don't want to scare the pack of badgers hibernating under the dashboard".

I've pledged to myself, however, that I will crawl back under the car to finish grinding the spot welds on the new floor when the temperature reaches 50 degrees.

However, this doesn't mean that I can't do other stuff. One thing I found to do was to buy a dash clock. I don't like that blank spot between the speedo and gauges so I decided to fill it. Tachs are great for racing but I'm a cruising and commuting kind of guy so I wanted a clock. A kind gent in a town to the North met me in a McDonald's parking lot and traded me two $20's and a $10 (you do the math) for a clock out of a 67. The picture looked good and you can buy quartz conversion kits for them these days so I bought it.

Here's the pic he sent me. The clock looked this good in real life too so I was pretty happy with the purchase.

I was a bit disappointed when I attempted to fiddle with the one knob that the clock has and it was really difficult to turn. Rather than force it, I decided that the internals were very dirty and assumed that since it was cold out, the old lubricants were clogging things up. I mean, how bad could it be.... right?

I didn't know anything about how these clocks work but ignorance has never stopped me from taking things apart before soooo...

I got the back off (by undenting 3 divots) and I'm no rocket scientist, nor a horologist for that matter (Horologist: Noun, Someone who makes or repairs watches), but even I could tell something was cuckoo about this clock. This picture is fuzzy but can you spot the first problem? The stack of gears to the left in the movement, which I later discovered to be the winding mechanism is out of it's pivot and tilted all, well, wrong.

I needed to loosen the top posts to allow the winding assembly to drop back into it's pivot so I needed to first remove the solenoid on the top which was held on by 3 screws. I also discovered a broken contact tab... uh-oh. The tab is laying on the table between the clock movement and the solenoid and belongs on the top of the winding assembly (the stack of gears that was out of whack in the picture above).

These clocks use a pretty ingenious principal to operate. They are basically just a wind-up clock for which the spring-loaded winder only winds about a half turn at a time. The winder contains a weight and an electrical contact (the broken tab above) . The solenoid's electrical contact remains static but when the winder winds down, the winder contact approaches the solenoid contact and they eventually touch causing the solenoid to fire with enough force to cause the winder to fly back to it's fully wound position (assisted by the mass of the weight attached to the winder). This process is repeated every 2 1/2 minutes or so. This understanding of how these clocks work was an important step towards the frantic realization that this particular clock is a goner without it's winder electrical contact which was now laying forlorn upon my dining room table.

Now, a less cheap person... that is to say, a person who is not me, would simply purchase a quartz movement online, plug it in and call it good. But here I am with a clock already disassembled, a broken $50 clock. Those new quartz movements cost around $70 so stay with me here while I do the math. 50 + 70 = 120! I'm not paying $120 for a clock! I would have just bought an entire, working clock for that with a refurbished face or maybe even a repro tachometer. Have I mentioned that I'm cheap? Okay, okay, it's not all about the money. I also like a challenge (have you seen that 68 convertible I'm working on?)

Before I started to repair the clock, I felt the overwhelming need to clean it first. I didn't want to risk damaging the numbering on the face so I removed the face and it's backing plate first from the movement.

The movement is held on by 3 posts inserted through rubber grommets and fasteners. Here's the movement just after being removed from the face backing plate. The old grommets were brittle and destroyed in the process. The gear on top is the where the clock's hands are mounted.

I basically dipped the movement into acetone after first testing the a small amount of acetone on the plastic gears with a Q-Tip. No problem. The movement cleaned up nicely and I finished it off by spraying it lightly with electronic contact cleaner. Radio Shack carries it in a type that includes lubricant.

Before reinstalling the movement on the face backing plate, I needed to replace the 3 rubber grommets. I bought some 1/8" ID x 11/32" OD grommets from a local hardware store that fit perfectly. Here are the grommets installed on the backing plate.

The next task was to get the clock generally running before I went to the trouble of fixing the broken contact. I loosened the 3 posts on the back side of the movement which are threaded and hold the assembly together. I was able to position the winding mechanism back into its pivot points and after some trial and error was able to get the escapement wheel thingy tick-tocking away when the winder was ratcheted to it's wound position.

So, to use this thing in an actual car, I need to get the contact back on the winding weight. I chose to solder the tab back onto the brass plate portion riveted to the top of the weight so I needed to remove the weight from the rest of the clock movement which, sadly, required me to basically break what I had just gotten working. This was a necessary evil if I ever wanted the clock to work beyond 2 1/2 minutes, however.

Here's the back retaining plate popped off and laying next to the now-free winding weight assembly.

I carefully aligned the broken tab with it's estranged wheel and filled in behind it with solder making use of my Harbor Freight pen torch which came in handy to get the winder weight assembly hot enough to flow the solder well. The last thing I wanted while the contact was being pummeled by the solenoid was for the tab to pop off again. I filled solder in behind the contact to provide structural reinforcement, kind of like a gusset.

I then reassembled the movement with it's repaired winder contact. It's hard to give advice here since there's so much you have to ensure is back in it's correct position. However, the most important things to check are that the winder's ratchet spring is loaded against the ratcheting gear and that the balance wheel spring is not loaded to either side (i.e. - it's balanced) and is in contact with the escapement lever.

I re-tested the mechanism by winding the winder and the balance wheel started doing it's balance thing and the escapement wheel started doing it's escapement thing, so I smiled.

The next thing to do was to reinstall the solenoid board. It had a nasty 41-year-old rubber washer that separated the positive and ground but holds the ground tab against the casing so I removed it and replaced it with a rubber grommet that I had cut off one side of to make a similar stepped rubber insulator.

I wound the winder, attached an old 12V laptop power supply and waited for the winder to wind down and contact the solenoid. CLICK! The solenoid slapped that winder back to it's full extent and has been doing so every couple of minutes for the past several hours.

You can see the contacts at the back of the clock next to the alligator clip on the circuit board. The winding weight rotates counter-clockwise (facing the .. um.. face) and brings it's contact (the lower contact) toward the solenoid contact (the upper contact). You can't see it in this picture, but there's a speed control on the other side of the movement that contacts the spring of the balance wheel. Moving the adjustment one way or the other makes the clock speed up or slow down slightly to allow for calibration.

After I finish calibrating, I'll put the back back on, paint the hands, and box the clock to be installed in Ol' Rusty sometime early this Summer (I hope).

Update 1/13/2009: I've calibrated the clock to within 5 seconds every 12 hours and put the back casing back on. As a last note, these clocks have a self-adjusting mechanism in them. Once you get them calibrated close using the internal speed lever, you can just adjust the time using the adjusting knob. Setting the clock forward speeds it up and setting it back slows it down.