Projects Tomcat’s Crazy '31 Model A Build Thread (2010-?)

Just now seeing this thread and catching up. Incredible skills and amazing save! Well done!

 

Thanks for looking drdave , and thank you for the kind words.

 

Just finished reading this entire thread. Fantastic build!

 

Wow. Thank you!

 

Well before tackling the fuel tank I decided to re-visit the rear sheet metal. After adjusting the fit on the rear most heavy sub-rail and then bolting the tail light panel to it, I discovered the gap to the trunk lid was too large, probably 1/4"+. Seemed like it fit better before. Sometimes sheet metal can be really annoying!


I made some optional 1/16" shims for the bottom.


They are set back and not really noticeable from the outside. Who knows, maybe this stuff will fit better later


On the inside of the tail light panel there's some backing plates where this panel ties into the quarters. I didn't like the weird crappy mismatched holes/slots and they did not match up well with the quarter panels either. Out they go.


To get a good match to the factory holes in the quarters I partially welded some holes up then using a dremel bit was able to effectively move the holes.


New backing plates fabricated with match drilled holes.


Plug welded in place.


The top edge radius on this piece needed to be trimmed for a better fit under the lip. Man, so many things I didn't notice before.


I made the rear most floor section removable so that needed some holes.

 

Unboxed the fuel tank and got a nice surprise. The box was not damaged and the tank was wrapped in a plastic bag. They obviously have no quality control or don't give a crap.




Got the damage ironed out and pressure checked the tank. The weld seam is still good so I moved on to mock up.

 

Well hell, it's been a while so here's an update on my crazy ass project. With a good idea of how much the fuel tank weighs full with 16 gallons of fuel in it, I needed to come up with a pretty solid way to mount it. In the event of an accident the forces involved would be fairly substantial.

I wanted to strengthen the floor and spread the load out as much as possible. My thinking was to bridge the floor seams and tie the floor panel to the sub-rails as well as incorporate some re-enforcement for the seat belt mounts. I also wanted to minimize the number of weld joints and make the whole deal bolt in. Later I'll tie the rear bulkhead/firewall structure in as well. I'm still refining the design, but here's what I've done so far.

Unfortunately, I started off with 16 ft. of bad material (1/8" x 1-1/2" flat bar) that I had to throw away.

After a few 90 deg. test bends it was obvious this steel was junk.


Using some poster board and some new steel I started wrapping my head around the concept.


I set the filler neck in place and slid the tank back far enough to "hopefully" make it easy to fill. After finalizing the placement I had an angle for the rear strap mounts, so I made these from some rectangular tubing.


A shot from the rear.


After plotting out the curves and flat sections of the sub-rails I eventually got the end pieces bent on a crude fixture cobbled together. Of course each side was slightly different so it took some time to get a good fit.




Bend fixture.


Starting to look like something here.


After fabricating the center seat belt re-enforcement plate it got clamped up for welding.


Here's a detail shot of a weld prep. Every joint gets this on both sides for full penetration welds.


After all the pilot holes were drilled and the final rear strap mount positions were figured the curved pieces were cut to length and radiused then tacked and welded.


A little metal finishing on the bottom side.


The next step was to match drill some holes, pop in some Cleco's, and drill holes in the sub-rails for the 3/8-16 threaded weld bungs. The outer seat belt holes will soon get 1/2-20 threaded weld bungs. Everything else 5/16-18. I'll be able to install bolts and washers from the bottom side to further beef up the tank and belt mounts.


Here it is prior to match drilling the rest of floor panel holes.


I ended up shortening the tank support pieces to allow room for the rear bulkhead/firewall attachment and then added a couple more pieces directly under the tank supports that contour the floor. These will get some vertical gussets as well. The tank strap details are up next but it's a 100 deg. here and I need a beer!

 

So here's my version of the fuel tank straps. I started with the Tank's Inc. SST straps kit and some 2" wide x 1/16" thick Neoprene strip. Then, after looking at some big truck tanks for ideas, I went looking for some T-bolts. Ended up finding some rated 3/8" T-bolts and the 3/16" SST rivets at McMaster-Carr.

The straps come flat with one end folded over and punched with a bolt hole. So, starting at that end, I drilled my support frame for the 3/8" bolts then slowly formed the bends over the Neoprene strips.


Next, I made a template to figure out the slot and rivet placement for T-bolt ends.


Using the template as a mock up gave me a pretty good idea of where to cut the straps.


Being a bit nervous and not wanting to screw this up, I decided to make a test piece out of the excess strap material. This would also let me try out the rivet installation. After figuring the bend line (2-1/2"), and convincing myself I could pull this off, I transferred the pattern to the straps.


I only drilled one side for the rivets and cut the slots. I figured now was a good time to polish this area.


Here's a shot after bending the loop and some more polishing.


After clamping the test piece and match drilling the holes I tried a couple rivets with my trusty long barrel air hammer. The bit kept slipping off the rivets and I damaged the test piece. To prevent this from happening on the real parts I made this gizmo.




After polishing up the rivets I went for it. This was quite tricky as things were shaking like hell and moving all over the place.


After trimming the Neoprene I did a final fit check before welding the T-bolt mounts. Like everything on this project, it took a lot of work and patience, but I got it done and I'm pretty happy with how it turned out.


Detail shot of the front side.




Now I can move on to the rear bulkhead/firewall and seat belt mounts. Happy 4th of July everybody!

 

Outstanding work TomCat, as usual your work is flawless.

 

Awesome work!

 

Thanks man. I have to admit I've had my fair share of mistakes and redo's . More than I expected for sure. Lots of trial and error to get this far but I guess that's all part of the deal.

 

Thank you sir. I'm eating this elephant one bite at a time!

 

@tomcat11 hoping you've made some progress and looking forward to an update. Cheers!

 

Great work so far. Keep the updates coming.

 

@34 5W Paul & @Hot Rod Ron thanks for your interest. I have made some progress but it's been slow going. Originally, I had intentions of making this a street/strip car.

A while back I had the seat installed and was deciding on whether or not to put a roll bar in it. This would make mounting the seat belts a lot easier and would add some roll over protection, but it could also create a hazard on the street. Well, after strapping on one of my old racing helmet's, I sat in the car and found I had only about an inch of head room.

To get a proper legal (and safe) roll bar in there I would have to start over with some bucket seats that had a lower seating position and ditch a lot of the work I've already done on the seat, the seat mounts, and the steering wheel position. Not to mention more $$$!

Since the car would be mostly street driven I decided against a roll bar but, still needed a way to mount the belts. I absolutely hate modern retractable seat belts. Do they work? Sure. But in a Hot Rod they don't look like they belong and you still have to mount them. You start to see the dilemma here especially working with this tiny ass car.

Well that's enough blabber. I'll post some pictures of what I came up with. It is still a work in progress and has become a bit complicated.

 

Thank you for posting & describing, the construction details. Learned a few things. .
Marcus...

 

Just read through the whole thread again. Excellent fab work. Lots of good ideas for mine.
Thanks for sharing all you are doing. Very inspirational.

 

@nrgwizard & @Bugguts thanks for the kind words guy's. Long way to go yet, stay tuned...

 

Well it's time for a long overdue update. I have been working on this rear Bulkhead/Firewall for months and months and it's probably the most ridiculous thing I have ever fabricated. It may look like overkill to some but I had three main objectives in mind 1) Seal off the trunk area which will house the fuel tank and battery, 2) Make it removable and bolt in, 3) Make it strong enough to mount the seat belt shoulder harnesses.



The previous "builder" welded a piece of 1" x 1/8" wall tubing below the rear window. The body around the window opening is welded to that tube so rather than run into issues removing it I left it in place. Had the original wood been in place I would have done this differently.

Vertical tubes with flanges at top bolted with 5/16-18 Gr.8. Bottom bolted using 5/16-18 Gr.8 in double shear.


Holley float bowl fitting gaskets which are .020" thick were used to space out the bottom tabs to allow for paint and ease of assembly. The tabs will be just tacked because I'm sure this stuff is going to move around after welding.


Added some gussets to the top flanges.


Center structure pieces fabricated from 1" x 1/8" wall square tubing and tacked in place. Behind it you can see the piece of flat bar that will also tie it to the body. Sorry for the blurry photo.


Here's a shot from the rear showing the re-enforcement plate that will sandwich the double layered body material using ten more 5/16-18 Gr. 8 bolts. This tucks in nicely below the lip and is hidden with the deck lid on.


Made a long scribe tool to mark a reference plane on the body.




Since this will be a three piece bolt together bulkhead, I started making parts for the two outer sections.


Here they are bolted to the main structure. Also added pieces to the top for a mounting point and sheet metal support.


Curved end and vertical pieces added.


Main structure set up for welding.


Made the harness mounts from 3/16" plate.


Half sections of 1" x 1/8" wall round tube were welded onto the back side of the square tube to provide a radius for the belts to ride on, They are positioned 4" below shoulder height. Same as you would have on a proper roll bar.


Harness mounts welded in.




Belts mocked up with Schroth Racing pivot bushings.


Tabs for Sheet Metal mounting.


Strips and Tabs welded to main structure.


Passenger side end piece with mounting tabs welded.


Bottom tabs welded to the
fuel tank base.


Outer frame attachment points to stock Model A body.






Main structure rear mounting.


Here's the whole enchilada assembled. 75 pieces in all. I think it will be strong enough. Hopefully I will never get the chance to find out!

From the back.


Next up is fabricating the Aluminum panels. Two pieces of 5052 H32, 28" x 28" x .050" thick cost me
just over $200.00! Crazy prices on material these days, Yikes!

 

Lots of thought has gone into that bulkhead! I can see where the time has gone!

 

Perfection always takes longer than we expect but the results are indeed perfect. Well done, amazing detail.

 

Holy cow. I think that should be strong enough even if by some freak event your gas tank is turned into an 800 pound gorilla!
Nice work!

 

That sounds like inspiration for an art piece

 

Great work...and nice to see this thread again!

 

Thanks all, hopefully the progress will come a little quicker from here on out.

 

Ck your PM

 

There is no kill like overkill.

 

It is recommended that each anchor point withstand a minimum load of 15 kN. That's 3,372 lbf.Physics is a funny thing, until it's not.

 

Tack welded some flange nuts on the floor crossmember for easy assembly.


Started the rear bulkhead sheet metal yesterday.


Today I drilled and tapped 10-32's and screwed it on.


From the back. Still has protective plastic so scratches just peal right off!


Started making patterns for the outside panels. Gotta eat some more cereal now so I have enough card board.

 

Switched gears to the outer seat belt anchors. Holes in the sub-rail walls (top & bottom) for the weld bungs were drilled and opened up with a die grinder and Dremel.


The 3/4" O.D. bushings were opened up to 7/16" I.D. but were about .050" too long.


I put them on my high dollar lathe and machined them down.


Since they were already machined it worked quite well and was very precise.




90 degrees here today so welding these in the moring. Stay tuned, more metal madness to come.....