Tuesday, February 23, 2021

Don't underestimate 3D printed tools

Previously, in the build...

I'm using a third-party fuel tank in the car. This means I can't use the firewall that shipped with the kit, so I have to make my own.

I've elected to make it by riveting together flat panels with aluminum angles. So this is an angle here - nice and square. But I don't want it square, I want to open it up a bit, to about 112 degrees, to match the sloping front face of the fuel tank.

The first step is to anneal the aluminum. This is 6063-T52, which is heat treated to make it strong. But I want it soft.

Neat trick I learned - regular old Sharpie makes a pretty good heat indicator for this - just heat your aluminum until the squiggle disappears, and then let it air cool.
Then I just squeezed it in the vise between these 3D printed shaping dies. These aren't anything special, just PLA plastic. I got the idea by watching the YouTube channel "Stuff Made Here" - one of the things he does is to use 3D printed (much nicer and stronger than these) dies to stamp sheet metal parts. I figured it would be worth a try.

I am simply amazed at how well it did work, though. I put some grease on the dies, and just clamped it in the vise, loosened it, moved it along an inch, and repeat for the length of the angle.
Came out spot on, over the whole length. Way plenty good enough for my purposes.

The dies do show some deformation and wear after the one angle, so I am currently printing a new set with a slightly modified design. I figured the first set would be completely destroyed, though, since I only used 30% infill. The new set will be 100% infill, which more than triples the print time.

It's amazing when a half-assed plan comes together like this.

Tuesday, February 16, 2021

Worked on brakes this weekend

This was a weekend for brakes. Here in the front, I installed a third-party bracket that allows me to put these big Brembo calipers on the Subaru knuckles.
I'm using the same (massive) discs in the rear brakes, and the emergency/parking brake calipers don't quite open up far enough to squeeze them.
So I bought some .080" aluminum stock and made a couple of shims to space them out a little.
Success! Here is a rear knuckle with everything bolted up.

I also did a bunch of thinking and planning about the firewall at the rear of the cabin. I believe I will not be using the firewall sections provided with the kit, but I have not yet decided 100% what to replace them with. Options include .063" aluminum, .125" aluminum, mild steel, and carbon steel; and welded or riveted construction.

Tuesday, February 9, 2021

Installing the rear knuckles

So after I got some brackets and links set up the other day, today is the day I actually got them on the car. Here's the rear knuckle assembly on the driver's side, bolted up to the trailing arm and the lateral arms.

Note the spiffy adjustable forward lateral links - those should help dial in the rear alignment.

Here's both sides at once! Excitingly, the next section of the build manual is called "Install Driveline." I'm not sure if I'm actually going to drop the engine and transmission in next, but it's very, very tempting.
Here's a look at just one knuckle, with most of the connections faked up. There's also a coilover that goes in here, but I think it's going to be a while before that goes in. I certainly have to get the engine, transmission, and drive axles in before that.
On a side note, I finally took the time to organize all of the hardware that came with the kit. Not every cell in these totes is full, but a lot of them are. This should make finding particular fasteners easier, compared to my old method of rummaging through a cardboard box.

Sunday, February 7, 2021

More rear suspension - brackets and links

I'm to a point now with the seat mount that I can't do much until the harnesses show up - then I will get to mounting tabs for the hip and anti-submarine belts, and finalizing the position of the seat. Instead, I got some work done today on the rear suspension. 

First, I bolted up some brackets to the  rear knuckles. These will allow the attachment of the coilovers and some control links.

Here are the control links being assembled on the bench. They have end links threaded into the tubes. Half of them are left-hand thread, so they will be adjustable when mounted in the car, to tune the rear alignment.

They have recommended initial lengths, measured from center to center, so I needed a way to measure that well.

A little 3D printing gave me these doodads. They fit in the end links and let me get a measuring tape on the centers of the holes.
Then, just by twisting the center tube one way or the other, I could tune the length of the assembly. Once I had it to length, I spun the jam nuts down and snugged them up to prevent any slippage.

I have new lateral links to put in as well, and then I should be able to get the rear knuckles on the car.

Tuesday, February 2, 2021

Seat mounts, again

Yesterday, I got the outboard, driver's side seat mount built. Today, I finished up the inboard mount and got it all mounted.

There's still a bunch to do on the mount; I have to make a mounting point for the hip belt portion of the harnesses, which is going to involve a little welding. Then the whole thing wants paint. And I have to make a tab for mounting the submarine belt, and get that mounted to the frame.

 But overall, here's what the driver's seat will look like. Of course, the passenger side will be an additional story.

Sunday, January 31, 2021

Back on the seat mount

I ended up not liking my work on the previous seat mount setup, so I started over today. I took a fresh piece of 2" flat steel, and started measuring and marking it to get bolted both to the frame of the car and to the seat bracket.
We're getting a little closer here. All the green pieces lying around are marking tools I 3D printed to help me get lines drawn on this piece of steel. Here we see the first two bolts in and all of the holes drilled.
And here it is all bolted up. It's not quite done yet - it's going to need a bit more work there on the aft end to trim it to length and get a tab welded on to mount the harness to. I'm designing as I go. But the holes are drilled in the frame, so this is where it goes, forever.


Monday, January 18, 2021

Brazing aluminum in order to modify the firewall.

Since the fuel tank I will be using for the build is not the tank Factory Five supplies with the kit, I am going to have to make some modifications to the supplied firewall. It comes in two portions. One of them, shown here, will want to be stretched a bit in the horizontal leg; the other one will need to have some material removed.
Since I'm not set up for welding aluminum, I have been doing some tinkering with brazing. I bought some test pieces, and I cut them into chunks. This is 1/8" aluminum flat bar, cut into nonspecific lengths - but these are maybe 3 1/2" long.

Using a flap wheel on my grinder, I beveled the edges where they will be joined, and also went over the margin to remove the normal oxidation.

Then I clamped them to a piece of steel scrap and sprayed them with non-chlorinated brake parts cleaner to remove any traces of grinding dust or oil or other contaminants.
Then I heated them with a MAP torch and filled the groove with brazing material.
Here's a previous piece I did - after this one was cool, I used a flap wheel again to smooth out the braze a little bit. It's bent into that S shape because I tested its strength by beating it with a hammer. The aluminum bent, but the brazed area did not bend or crack at all.

Seems like this just might work out.