Fear Commitment? It's a Chassis Update!

Well, It's been another 6 weeks. Work has been insane. Family matters have insisted on their due attention, but I have the rear suspension about 75% complete. I still need to finalize a little geometry for the top link before i weld it out and start on the shocks. I have something special in mind there, so stay tuned. Here are links to previous updates and a small thread I started about easy CAD design and CNC Plasma cutting of my rear suspension brackets. The rear axle is pretty much ready to weld out. I need to tack everything into final position and loose my TIG welding pro on it. I'll let the pictures tell the rest. Look for more when i get the shocks worked out.
Previous Episodes:
http://www.jalopyjournal.com/forum/showthread.php?t=169436

CAD designed brackets:
http://www.jalopyjournal.com/forum/showthread.php?t=178235

 

Is that top A arm a slider joint at the diff end? Works better if it is, assuming from the brackets that you're doing a 4 link + A arm locator.

 

No, It's a triangulated 3 link. The top half of the outer axle brackets will be removed after welding. If you look at the brackets, you'll see a curved cut almost all the way across. I put them on there to help with the jig work.

 

Excellent design !

 

Everything is tacked together now. The zip ties, magnets and bungees have been removed. I need to make up the top housing tabs and weld everything out. Next I'll add a light weight crossmember behind the axle and get the shocks in place.

 

WOW! Looks like it is gonna be fast

Rusty

 

Hey Rusty! I hope so. When are you gonna come see it in person? Is it gonna take another 'Round Up to get you down here? Maybe for the Drags in October? How about an update on your new addition?

 

I was going to ask if thats what you had them there for, I was like those cuts look kind of odd, then im like, well I guess its kind of hard to line up brackets on a cylinder, maybe they're for that purpose, I think those small details are what defines the genius in a well built machine, often times those little things are always overlooked.

 

I don't know about genius, but I do think I had a neat idea. Here's the next step on that piece.



And now, on to sweeping the frame rails. Bob Bleed, I hope you approve.

First, level the table, and then level the frame on the table. I used small pieces of masonite and used saw blades to get it just right. The screw jacks will lift a piece of tubing under the rails so that it moves smoothly. They have been raised up under the frame here and just slightly preloaded.



Then you find the right place for the kerf cuts and mark both sides evenly. I used a tungsten-carbide steel cutting blade in a 7.5" circular saw. You really need to try one of these. It is 3 times faster and cleaner than abrasive saws.


I cut the last inch that the saw couldn't reach with an abrasive wheel in my grinder and then used the screw jacks to raise both rails evenly to close the cuts. Two cuts in each rail gave about 3 degrees of incline.


This is what 5.5 degrees looks like with four cuts...


I will keep the rail true with C-clamps and Vee the joint slightly before welding them shut.


I plan to cut out some stylish fish plates to use on the outside of the rails for insurance, though the strength of such a joint is pretty reliable anyway, if welded properly.
The axle housing is out to be welded by my tig welding fool, Cam Bierman. I can't afford to pay him what he is worth, so please take a little time to check out photos from his shop on my MySpace page or look over the race team website below. He's the crew chief and chassis guru for Howard Brown, Brown Motorsports. He taught me most of what I know and I count him among my best friends. Stay tuned for more. I'll have that axle housing back soon.

 

Are you going to gusset the crossmember that supports the upper suspension link? Seems like a couple of tubes to the frame kickup would add substantial strength.....

 

Yes. I plan 2 things. A drive shaft loop of some fashion to make 2 down tubes from there to the lower crossmember, and I think a webbed gusset large enough to be creative on both front and rear of the intersect with the frame rail. Still mulling that over.

 

wow. now I'M jealous!!! nice work!

 

Finally! I got the chassis back yesterday. The rear suspension has been welded out as far as I have built it so far. I finished welding the sweep up front, but still need to grind that out and finish it. I'll get back on that when the front suspension goes in. Like that shiny NEW Muncie? Auto Gear Equipment M21 with .86 OD 4th gear.



Right now, I am working on the rear shock install. Some of you have caught on that I am doing something different. I was going to hold all photos untill completed, but I have never been much good at keeping secrets. Here's a look at the general idea. These are coil-overs, but I didn't want to see them from behind the car, so... This is a ball park location. I will be playing with several different positions to see what will make the most sense. These also show the rear suspension in better detail.

 

Very nice and well thought out !

 

That's some good looking fab work.

I don't get how the coiliver is going to attach to the rear end? Your pictures
show both ends attached to the frame rail.

Instead of coilovers, have you thought about torsion bars?

 

Thanks Guys.
I did consider torsion bars, but they wouldn't be as easy to adjust ride height.
The shock is anchored at the top to the frame. The bottom ties to that rocker arm which has very near a 1:1 ratio. It is longer on the axle side to give slightly more travel than the shock has. The axle will be linked to the other end of the rocker by a short link having spherical rod ends on both ends. The link will adjust ride height by about 2 inches without disturbing the spring preload and installed height. It also gets them up out of sight.

 

You might want to check the front crossmember and make shure it still matches the caster you are going to run in the axle as having it welded in before you swept the frame would = giving it more.

 

Won't be an issue. I'm leaning toward 1/4 elliptical springs now, so the crossmember is just keeping the radiator out front. Still tossing around the choice between hairpins or heavy bones. I'll mock all that up for real after I finish the shock install and motor mounts.

 

Well, the rear suspension has been worked out at last. The whole idea was to have a fully adjustable suspension that wouldn't be seen and distract from the vintage salt racer look I am aiming for. I flipped it around to the rear after deciding the front install was too cluttered. The last pic is an idea of what will be visible from the rear. I need to put in the other side and get the gussets made up. Also a peak at the motor mounts I designed in 5 minutes flat using my cad stuff. CNC plasma cutting is the bomb! The frame uprights will mirror the sides of the rear suspension crossmember.






To do list: finish rear shocks, install motor mounts, install trans crossmember, design and cut gussets front to rear, blah, blah, blah...

 

Really nice work! I like the rocker shock mounts.

 

Very nice! Awesome fab work and design.

 

The real job just never lets up! Very little progress of late, and now I am preparing to hit the road for a year with a new position for my company. It's an opportunity I can't pass up, so the best I can hope for right now will be getting a little done on some of the weekend visits home.
I did get the frame down on the ground with the cab sitting on it for a little perspective update. I'll say the frame is about 80%. I need to weld it out and install the front end, finalize the motor mount position and weld out those and the transmision cross-member. Then I can add running gear to get my roller. It's a couple of inches lower than it will actually wind up. I planned it no lower than 5.5 inches, but it will come in at a speed bump friendly 6.5 inches.

Here's the latest view from the shop...








Stay tuned. I may be pushing it back to Round-Up '09, but I have vowed to keep it going. My wife insists that I finish it before I start the next project. At least I can spend some of my time on the road planning the electric boattail! (I'm not a tree hugger, I just like to shake the branches a bit. )

 

Man that sucks it ain gonna make Roundup 08. I still think you can do it, Get your son out there to help. Great progress. Who do you use to do the cutting, How much do they charge per piece?

Rusty

 

that's clean. nice rear shock set up

 

Neat set-up - you'll have a great looking rear end when it's finished.

 

That looks MINT ! I was looking at building the same thing only a tad bit different. I was going to flip the shocks forward so the cam was lower. I will gain 6in of bed floor. Very nice work.

 

It's an inspiration to see what talented people can do! Some of us just have to muddle through. What's ahead for the body?

 

Where did you get your frame from? And where did you pick up the two adjustable jack stands? Those are nice,,,.

 

man nice work ! love that shock set up .

 

Thanks guys. I appreciate the encouragment.
The body needs to be trimmed for tranny clearance at the base of the firewall so I can pull it all the way forward to the right location, then I will need to finish mounting it so I can get on with welding it out and building the tunnel.
Those screw jacks were loaners from the shop. Probably out of a commercial catalog like Grainger or something. I'll check.
The basic model A frame I started with came from Randy at LRS inc. Very nice work, very fast and very well priced. I stretched and tweaked it into the thing you see here. http://www.streetrodderstuff.com/
I was home again this weekend. I've only been here 3 days since Jan. 5th. I am back to Miami today. I did get the motor mounts in and a temporary trans crossmember that will allow me to build the real one in place. Here's a few more pics. My welding has improved enough to be sound, but still not anything as pretty as Cam's tig welding. Oh well... The cab is back about 10 inches too far until it gets trimmed. I set the motor about 1.5" forward of the usual to help with cab placement. I think I will be OK with a short water pump. We'll have to see what radiator I can fit. I'll be on to the front suspension very soon.