I can't come up with cleaver titles anymore.

More work on the Uzi.  Last time I showed off my overly complicated CNC'd receiver bit.  This time I'm going to start putting it together.  I'm not using a jig, so I'll have to use the parts themselves to keep everything aligned.  The first thing I did was weld some bits into the new receiver.  After some careful hand fitting, I welded in the barrel restrictor ring/feed ramp, rear grip mount(removed from my original receiver chunk), and most importantly the blocking bar.  The blocking bar is necessary for all semi-auto Uzi builds.  It's sole purpose it to prevent a full auto bolt from being installed into the gun, and it must be put in before the receiver is complete.  Even before it's complete, without the blocking bar installed you are in possession of a machine gun receiver in the eyes of the law, so it's best to put it in as early as practical.  Here you can see the parts in place, as well as the weld going down the center where the two machined halves meet and where the rear grip mount welds have been ground down for clearance.

I'm going to be using my barrel to help keep things aligned.  The problem with that is that my original SMG front trunion and semi-auto barrel don't exactly match.  One of the things IMI did when they started exporting a semi-auto version of the Uzi was make the semi-auto trunion smaller in diameter so that a full auto barrel wouldn't fit.  That means that the hole in my FA trunion is .040" bigger than the barrel.  That makes for a sloppy fit and way too much wiggle room for my liking.  I was going to machine a bushing to press in, but then I decided that was way too much work because it had to be so thin.  It occurred to me that shim stock would work great for this.  I used some brass shim and made myself a bushing, carefully filing the ends so that it fits perfect.  Since this is a pistol build and I'm legally allowed to use a short barrel if I want to, I'm not worried about it being removable.  You can also see how this front stub looks practically new.  Even though it came as part of the same parts kit, it definitely didn't come off the same gun as the rest of my parts.

With that set, it was time to put things together.  I had already welded the sling swivel/front grip mount section of the receiver to the front stub using my machining jig to hold things square, so it was time to attach that to the main bit of receiver.  I'm using my barrel for alignment, and here's how everything fits together.  The rear barrel restrictor ring/feed ramp ring aligns the new receiver to the front trunion. The Uzi headspace is determined by the bolt contacting the trunion, so nothing here needs to be ultra precision.  Since the barrel is new, I've got the exposed parts covered in blue tape to keep them from getting scratched.

Now the exciting bit, welding without a jig.  I have to make sure everything stays straight, and I want to get full penetration welds, without burning through the sheetmetal. Enter the copper backer.  Steel won't stick to copper when welding, so you can weld and get full penetration without leaving blobs of weld on the back side.  I didn't actually have any thick copper sheet, and it costs more than I wanted to spend for the little amount that I needed, so I decided to think outside the box and into the home improvement store.  I bought some copper plumbing connectors, and smashed them flat.  Presto, $.49 instant copper plates.  The barrel takes care of our axial alignment between the pieces, but I still had to get the right length so that everything fit together like it was supposed to.  Since the rear grip mount is welded to the new receiver, and the front of the grip locates off the protrusion welded to the front stub, I could use the grip frame it's self to set the length of this section.  I carefully fit the parts so that there was zero gap between them, then I used a variety of vice grips to hold everything in place, backed by my copper plates.

After tack welding and checking to make sure everything was straight and in the right place, I burned in some welds.  With that done, I decided it was time to cut the ejection port in the receiver.  I also dressed the welds some, because I'm impatient.  Here's where we sit at the end of the day, actually starting to look like something.

Spoiler Alert!

This post is going to have a lot of words and few pictures, I'll try not to write a novel, but no promises.  I'm a bit disappointed that I didn't take pictures of this process because it worked really well. 

Originally I bought an Uzi receiver flat with the intention of making a bending jig like I did with the AK.  But after reading up on it, it's not a straight square bend like the AK, the nose section of the receiver has to wrap into a tube.  I wanted to reuse my original front end and Hebrew marked rear section anyway and I decided it would be a shame to cut apart a $70 receiver flat just for the bits I needed.  So I decided to do it the hard way.

Spoiler Alert!  I have a CNC mill.  It is not big, and it is not fast, but it gets the job done.  It's a Seig X2D that I converted to CNC myself.  Maybe some day I'll give it it's own build thread.

I decided to make my receiver section on the CNC.  Why?  Because I have way too much time on my hands, apparently.  It seemed like a good idea at the time.  More important than why is how? How do you make a .070" thick sheetmetal part on a CNC mill?  Milling it from a solid block of steel would be way harder than it sounds because as the walls get thin the part looses rigidity and the side walls want to get either pushed away from or pulled into the cutter, making a vibrating mess with no chance of holding a tolerance.  So that method is out.

I decided to think more outside the box.  And into the tube.  I got some 2"x2"x3/16" wall steel tubing.  I'm using A500 grade tubing, which is about equivalent to 1020 carbon steel.  It might seem like it would be too weak for a receiver, but it's stronger than the 1010 steel used in the commercially available receivers(and flats like the one I bought).  Like the AK, the sheetmetal of an Uzi receiver doesn't see much load, so all it really has to do is hold the parts in.

So, how did I make 2" square, 3/16" heavy wall tubing into a 1.6" wide, thin sheetmetal piece?  I cheated, obviously.  This is the bit I'm kinda proud of, and I'm sorry I don't have any pictures of it.  After drawing up a CAD file based on measurements of my receiver pieces and available blueprints, what I did was machine the the sides of the receiver into the sides of the tubing, cut the middle out, weld the halves together, then machine the bottom.  In the pic of my mill above, I'm just finishing up the finish facing pass to get the bottom thickness set.  My welding jig to put the halves together was just a bar of aluminum cut to the right size, and it also served as a backer to support the thin sheetmetal sections so they wouldn't collapse in the vice for the last milling operation.  I elected not to cut the ejection port until later too so that the piece had a bit more stability while milling.  The holes for the blocking bar welds are sloppy as heck because I forgot them in the program and just used my mill as a drill press and I suck at hand drilling holes.  I'm not too concerned, they get welded over anyway.  Here's what I ended up with, one CNC made sheetmetal receiver section.

The Hebrew Heater

As is apt to happen, I sometimes drop off the face of the earth for very long periods of time.  Lots of things between where I left off and now, but I'll spare you the details.  What's important is that it's the middle of hecking winter and I have another wholly impractical project to work on.

Yeah.  The Hebrew Heater, ready to dispense some Jewish Justice.  The Uzi.  Why the Jewish jokes?  Because despite being the star of every 80's action movie and the Secret Service's sidearm of choice, the Uzi was actually designed way back in 1950 by Jews, for Jews, and manufactured by Israeli Military Industries(IMI) from 1950-present.  Like the AK, it's one of the world's most recognizable guns, and millions have been produced(so many that even my well used one is serial numbered in the 9 millions).  The Uzi been used by military or police units in over 90 countries, including this one.

There are a few varieties of Uzi parts kits on the market, original Israeli kits, and, in an historical irony, German kits.  The German military bought this Jewish weapon for over 25 years.  I decided I wanted the original, a genuine IMI built, Israeli used Uzi.  Like all machine gun parts kits, the receiver on my kit is torched to BATF specifications, and there are large chunks of the receiver missing.  Technically, it's now a pile of scrap metal, and no longer a machine gun.  Both the receiver markings and the safety selector markings are in Hebrew.

I'm rebuilding this parts kit as a legal, semi-auto pistol.  Why a pistol?  A couple reasons.  First pistols don't need to worry about 922r(which you may remember was a big deal with the AK, and I'm going to keep track or parts count anyway).  Second, by using a 16" barrel, I can convert it to a carbine with a shoulder stock, as is becoming popular with many off the shelf Glock pistols these days.  There are several Glock to carbine conversion kits on the market.  If it were built as a rifle, it could NEVER be made into a pistol.  Legally you can go one way, but not the other.

There are tens of thousands of semi-auto Uzi's here in the US already, so I could just buy one, but where's the fun in that?  To get this former machine gun together and be legal, I am going to convert the original open bolt system to a closed bolt, striker fired semi-auto.  When it comes down to it, Uzi's are dirt simple, and I've got some special, and overly complicated plans for this project. 

One last little bit of business.  In order to make it clear that I have no intention of using this as a machine gun, one of the very first things I did when I got my parts kit was grind off the firing pin from the original Uzi bolt.  It CAN NOT be used in a functional gun anymore.

The last bit

With the hood done, there is only one part of major bodywork left on the Viper.  When this car hit whatever it hit(probably a pole), it slid along the driver's door and into the quarter panel.  The side sill had already been replaced when I got the car.  The door was a total loss.  Even a cheap bastard like me could see that it was more trouble that it was worth to try to fix.  The quarter panel is another matter.  It could be replaced, but the damage wasn't too bad and I'm me.

Let's have a look at the damage, shall we?  You can see from the panel gap that the bottom of the quarter is shoved back almost 3/4".

The quarter is shoved back to the point where the quarter is almost touching the sill.  It's also got some cracking along the edges where it flexed too much, and you can see from here the split in the sill.

The inner sill is all cracked up too.  None of the underlying metal is bent, but the fiberglass is cracked in several places.  You can kind of see how the bottom of the sill is shoved back a bit too.

Here's the main crack in the quarter panel.  You can see that it's buckled a bit just below where it's riveted on.  You can also see the spalling radiating out from around the visible crack indicating that the crack extends under the paint a ways.

 
Fixing these areas will be just like all the other areas, with one minor addition.  But we'll get to that next time :)

All bondo'd out

I joked earlier about having the Viper out again before finishing last fall's updates.  Turns out it wasn't that funny, because it's true.  In my last post I started bondoing the hood.  It's time to finish it off.  One of the most prominent features of the Gen II Viper is the hood scoop.  The scoop is a plastic part, and after 15 years in the sun it's not the same shape it originally was.  Additionally, the scoop on my car isn't from my car.  I assume that the original was damaged in the crash so it was replaced.  What all this adds up to is a scoop that doesn't fit like it did when it was new.  The shape doesn't quite match the hood, and, since I re-fiberglassed almost the whole perimeter of the scoop hole, the gaps are all over the place.  Since I have the bondo out already, now's the time to fix it.  The easiest thing to do is to just bondo over the whole thing and sand it down.  First I covered the scoop in blue painter's tape, then I bondoed over the whole area.  The tape both keeps the bondo from sticking to the scoop, and provides some protection so it doesn't get too scratched up while sanding.

The bondoed area is so big because it needs to blend smoothly into the rest of the hood.  We don't want the scoop area to be a distinct high spot.  You also have to make sure to allow enough room in the panel gap for primer and paint.  If your gap is too small, the scoop won't fit once the primer and paint are applied.  After blocking the area down, and some minor tweaking of the panel gap, the scoop fits good as new(actually, probably better than new).

With all the bondo done on the hood, it's time for more Dura-tec.  If you remember back when I first described Dura-tec, you'll know that it's very similar to fiberglass resin.  It catalyzes differently than standard paints and primers.  When you mix regular car paint or primer with catalyst, while the work time, or "pot life" is only an hour or so, it can still take a few days for a cup full of liquid to actually start to solidify.  Dura-tec isn't like that.  Much like fiberglass resin, once it starts to cure, it gels up quick, and the more catalyst you use, the faster it kicks off.  If it does solidify in your paint gun, you go buy a new paint gun.  Why am I mentioning this?  Because when I Dura-tec'd the hood, I had a VERY close call.  My gun started spraying like it was empty, but it wasn't.  The Dura-tec started to gel up in the paint gun.  It took a few minutes of frantic acetone scrubbing to get my gun clean before the stuff turned solid.  At any rate, I did get my hood covered, and the hood is done until it's time for final primer and paint :)

I heart bondo

Seriously, at this rate I'll have the car out again before I'm done posting all the stuff I did last fall...  With the hood fiberglass done, it's time for bondo.  I've already posted why Bondo brand bondo is terrible and should be avoided at all costs.  My biggest complaints are that it spreads poorly, and sands hard.  I mean, it works, but you end up using more effort and going through more sandpaper than with other fillers.  There are much, much better products for not a whole lot more money.  My filler of choice is Evercoat Rage Gold.  It's about $20 more per gallon than Bondo, but the time and sandpaper it saves are well worth it.  Concidering the $800 I'm likely to spend on just primer, paint, and clear, an extra $20/gallon for filler is nothing.

The first thing I did was sand down all the fiberglass with 80 grit sandpaper.  All the 'glass was sanded close to the final panel height, and all the left over paint was removed from the repair area.  Then I mixed up a big batch of bondo and covered the whole area in one go.  The big blue tarp not only helps keep the dust out of the engine compartment, it also catches drips in the bondo.

If you catch the filler at just the right point while it's hardening, you can remove a whole lot of material very quickly.  Using my longest sanding block and 80 grit paper, I sanded the whole area down.  You want to use the longest sanding block you can because you'll end up with a flatter result.  NEVER use power tools for your final filler work.  If you do bodywork all day every day, you're probably good enough to get away with it, but if you're inexperienced, power sanders will leave you with a very wavy surface.  It quickly becomes apparent when sanding where the highs and lows are.  The highs get sanded down some more, and the lows get more filler.  Ideally, you want no more than 1/8" of filler thickness, any deeper than that could conceivably crack(though that's unlikely) and should be filled with fiberglass instead.  Pinholes in the fiberglass should be ground out too, to avoid problems down the road.

You'll notice that I bondoed right over the edge of the hood scoop hole too.  Since much of that area is new too, it also needed some work.  With the scoop as a guide, I used my die grinder, some square files, and a sandpaper covered popsicle stick to remake the scoop relief.  Here it is in progress:

I want to be sure that the curve of the hood matches the curve in the fascia.  To make sure they match, I made a simple template with foam core posterboard.  It'll get me closer than I can eyeball(and no, I'm not holding it straight in the top pic).

LEDing the way

The headlights on my '95 Impala SS are just awful.  The combination of poor lens design and barely adequate wiring makes for little light down the road.  They are so bad that I can drive around with my high beams on without passing drivers flashing their lights at me.  Generally speaking, upgrading the headlights is a lot of work.  The wiring is sized just big enough for standard wattage lamps, switching to higher watt bulbs requires relays be added or risk melting the wiring.  I'm also on my 3rd dimmer switch in this car, the previous two melted.  I've avoided upgrading the headlights partly because of cost, and mostly out of laziness.  But I came across a new solution, LED bulbs.  The price of LEDs has dropped significantly over the past few years, and they now make drop in replacements.  LEDs also use much less power for the same(or more) light output than standard bulbs, which greatly reduces strain on the wiring and switches.  So I took the plunge and bought some.

To my surprise, the headlights already in the car were already upgraded to PIAA "Star White" bulbs(which explains my melted dimmer switches).  Far from being white, they put off a fairly standard yellowish beam.  You can also see that around the base of the bulb the plastic is charred and melted a bit.  These bulbs run HOT.  I bought the LEDs on e-bay for around the same price as many of the "upgraded" standard bulbs.  They are 80w 8000Lm bulbs, that's an entire 50 watts less than the PIAAs, and they put out more light.   Here's what the new bulb looks like.  The old bulb is on the left, the new LED bulb on the right:

Installation is as simple as removing the old bulb, putting in the new one, and plugging the harness into the existing plug.  It's immediately apparent that the new bulbs are brighter.  Once again, old on the left, new on the right:

So, how do they actually work?  Well, the jury is still out on that one.  There is no question that they put out more light, but how they put it out leaves me a bit underwhelmed.  The pattern is much more diffuse with the LEDs.  They light up the sides of the road better, but don't seem to project out as far.  Since half my driving is at night down country roads, my biggest concern when driving is deer jumping out in front of me.  Having the sides of the road illuminated better could help avoid them.  Though the highs are definitely brighter, there isn't as distinct a difference between the high beams and low beams either. 

Lows:

Highs:

I'll give it awhile to get used to them, but for now I'd call it a wash.  On the plus side, I shouldn't melt any more dimmer switches :)