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PostPosted: July 14, 2021, 4:23 pm 
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My 2 cents is, bring your bars as close to the balljoint as possible, I hear you not being able to weld straight to the balljoint. If there's room for the knuckle to pivot, bring the bars along the side of the balljoint tab with an angle cut at the ends for a closer clearance.
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PostPosted: July 16, 2021, 10:34 am 
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@niko
The wood idea is a good one. Generally, I'm going you got to a more traditional design, more along the lines of the sketches sony1492 did. I actually have my 1" x 0120" DOM tube for the arms already.

@sony1492
Thanks for the nice sketches. They are more like what I'll end up with in my version 2 design.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: July 19, 2021, 10:34 am 
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By the way, what's the material of that bush ?
You mentioned MIG . I wouldn't be too comfortable with migging 4130 to mild steel .
Not to say it can't be done, but somebody with plenty of experience should put in a wise word .

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PostPosted: July 19, 2021, 3:34 pm 
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@niko
Thanks for that tip. However, all my parts are just grades of plain carbon steel.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: July 25, 2021, 11:38 pm 
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I've done a version 2 design for the lower control arm. I've upper the steel plate to 3/16" from 1/8". All other materials are the same (1" DOM arms, coilover bracket, etc).

I just finished it, and will look at it again tomorrow with fresh eyes, but wanted to put it up for comments tonight. I'm not sure yet how I'll cap the DOM arms on the ball joint end. It's simple enough that I feel I can make it with the tools I have except I will need a hole saw for the balljoing ring.

Cheers,

Attachment:
LCA V2 #1.jpg

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LCA V2 #3.jpg

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LCA V2 #2.jpg


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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: July 26, 2021, 10:38 am 
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I'd think your best bet for caping the ends would just be to weld them shut. Half a DOM tube is a pretty small area.

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PostPosted: July 26, 2021, 12:10 pm 
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Do you have room to add a couple gussets?...


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PostPosted: July 27, 2021, 6:08 pm 
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@Trochu
Hmmmm, I thought the opening might be too big. We'll take a look when I get them done as see if that will work.


@RTz
I do have room, Ron. Thank you for the suggestion.

Cheers all,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: July 27, 2021, 8:37 pm 
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Lonnie-S wrote:
seven13bt wrote:
Suggest attaching the front and back tubes directly to the LBJ collar. An example from my Locost:


That was my first thought, Ron. However three things persuaded me not to:

1) My DOM is 1" as is my screw-in ball joint ring, so the fishmouthed DOM will come above the edge of the ring - no shoulder. So, for me, not a good welding target;

2) With my MIG skills, I'm almost certain to spoil the threads because of too much heat added with such a large, continuous weld bead;


This is still the strongest and safest approach. Do you know anyone that can help you weld this area?

FWIW I've had issues with threads distorting during welding on past projects and did not have an issue when I used off the shelf threaded collars for my arms.

Another option would be to step down to 7/8" tubing in a heavier wall thickness.

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PostPosted: July 28, 2021, 1:51 pm 
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@a.moore

With the direct-to-ring approach, I'd definitely have to hire someone to weld it.

Although I understand the direct approach would be simpler and lighter, Andrew, I'm actually pretty happy with the plate approach. Mine's just a cruiser, so not a race or track car and weight isn't as big a consideration for me as with some folks. Plus, I have all the materials to build it now too.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: July 28, 2021, 5:41 pm 
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Hey Lonnie,

Even for a street vehicle you hit potholes which will pass loads through that critical outer end of the LCA. What is your front corner weight? It is reasonable to multiply that static corner wheel weight (converted to pounds force not pounds mass) by 4 as the extreme load the suspension would see on the road and ensure that the stress in the mild steel components are in the safe range for fatigue and yield. Due to those pesky leverage ratios the lower spring mount is trying to punch its way through your bracket. The 1/8" plate without gussets I do not think would be safe. Here in NZ you have to TIG all suspension components for road cars and I agree with the other guys (I also like MV8's suggestion) that the tried and true method of welding direct to the threaded bush seems the best option - it has nice wide load spread over the welds and is materially efficient.

We have threaded a brass or copper plug into holes when we have to repair machined castings, it helps absorb and distribute the heat and avoid distortion. You can actually weld right up to it and the steel won't stick to it, and then it can be unscrewed out after it has cooled.

I hear that you have the all you need to make it work, and I applaud you for opening up for other ideas - it is very easy to fall into a mindset. Watching this with great interest.

:cheers:

Marcus.


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PostPosted: July 28, 2021, 9:25 pm 
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Lonnie-S wrote:
With the direct-to-ring approach, I'd definitely have to hire someone to weld it.


Do what you'd like Lonnie, as I suspect neither will fail, but if you can weld like this:
Attachment:
DSC05717.JPG.jpg

I'd have zero concerns about doing it yourself!

One is easier to build, lighter, simpler, and stronger, but both will likely work.
I wouldn't worry about distorting the ring, they are pretty stout.


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PostPosted: July 30, 2021, 4:45 pm 
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@Kinetic Research

I don't have any accurate figures for corner weights yet, Marcus. I just have a "guesstimate" for them. I'll multiply by 4x just to see what I get. I've been pretty conservative and I suspect the finished car will actually weight less than my estimate, which I made for 2 people on board, 10 gallons of fuel and 100 pounds of cargo that includes the spare tire and a scissors jack plus lug wrench.

My guess on front/rear distribution is just based on what others have observed in their builds.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: July 30, 2021, 4:47 pm 
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@Trochu

Thanks for the implied positive comments on those welds. They're some of my better "weld boogers." :mrgreen:

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: July 30, 2021, 5:13 pm 
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Now that I'm on my own, I feel like I've got three jobs, and not a lot of time to work on the build. I'm working at getting more efficient, but now have a lot of "distractions" now that my wife used to handle. Aaaargh! It's very frustrating.

I do keep plugging away. I'll finish the LCA tonight or tomorrow, and then get to building it. Two of my recent distractions were doing a refinance on the house, and getting the Corvette back on the road. The latter was more of a financial distraction than anything else, but it took time to research things, find products and locate a competent shop to do the work, and then get the financials covered.

It's back now, and a much improved car. I need to drive it every day for a few weeks to get some miles on it before it goes back to the shop for a go-through inspection on the work done to date, plus gets the MGW shifter delayed at reassembly time by a parts shortage at the manufacturer.

Here's a photo of the rear suspension cradle with half shafts, differential, transmission and torque tube all cleaned up, gone through, and ready to reinstall. That's my Z06 on the hoist.
Attachment:
The driveline - July 2021.jpg


Cheers,


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Build Log: viewtopic.php?f=35&t=5886


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