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PostPosted: August 10, 2012, 5:17 pm 
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You will have to use the 1 3/4 turns to get 4 1/2" travel to see if that is enough to move your steering arm through it's full travel. 1 3/4 turns sounds pretty fast.


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PostPosted: August 13, 2012, 7:45 pm 
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So to make sure I have everything right here with the steering... It looks like I will need a 22"-24" Steering rack correct? Anything wrong here or that i might have missed?

The 1st pic is of the steering rack in relationship to the control arms and instant center
The 2nd pic is of the rack in relation ship to where it will be mounted and the steering arm

Attachment:
Steering Rack Length.jpg


Attachment:
Steering Rack Length2.jpg


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PostPosted: August 13, 2012, 11:17 pm 
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mjalaly wrote:
Anything wrong here or that I might have missed?


http://en.wikipedia.org/wiki/Ackermann_ ... g_geometry


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PostPosted: August 14, 2012, 9:29 am 
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cheapracer wrote:
mjalaly wrote:
Anything wrong here or that I might have missed?


http://en.wikipedia.org/wiki/Ackermann_ ... g_geometry



You are correct. I didn't mentioned that and there is a bit of confusion here. If I have zero ackerman, 1st pic, then the new location for the steering arm wont fall in the ideal location for bump steer placement.

Attachment:
Ackerman.jpg


Attachment:
Steering arm change.jpg


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PostPosted: September 24, 2012, 12:22 pm 
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Getting around to attaching the suspension tabs to the chassis and I wondering if anyone might have any suggestions on doing so and keeping things accurate. It looks like trying to measure for the center line of the car to the tab is fairly hard to do. I doubt the tubes are exactly where they need to be so measuring off of those might not work. I can measure from the ground up pretty accurately it is just in the Y direction that will be tough.

The tabs have not be notched in this model because i plan on doing it as i go to make up for movement during welding.

Attachment:
car mounts.JPG



pick up this magnetic tab holder really cheep ($11) which will help a bunch here and a few other places...

Attachment:
2012-08-27 15.24.37.jpg


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PostPosted: September 24, 2012, 2:52 pm 
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If you have the uprights and control arms fabricated, definitely use them to hold the tabs in place while tacking. I would mock it up and paint mark the locations of the tabs so you have a good reference.


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PostPosted: September 27, 2012, 11:15 am 
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Can any one point me in the direction of a rear steer quick steering rack that is 22"-24"?? I am not finding too many options.

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PostPosted: September 27, 2012, 11:35 am 
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http://www.woodwardsteering.com/

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PostPosted: September 28, 2012, 9:26 am 
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horizenjob wrote:


I had a long call with them a while back and pretty much they don't make manual racks in the ratios i need any more and that i should go to power steering. I will need to look at what i can really get away with and call them back.

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PostPosted: September 28, 2012, 9:32 am 
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I figured I would be smart and print out a full scale drawing of the tube so that I could make sure the tubes curvature matched the model.

Attachment:
IMAG0846.jpg



But.....Agggrrrr!

Any one know of how I can roll the tubes with out having it twist?! I think this tube is pretty much shot.

Attachment:
IMAG0852.jpg


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PostPosted: September 28, 2012, 9:41 am 
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mjalaly wrote:
Can any one point me in the direction of a rear steer quick steering rack that is 22"-24"?? I am not finding too many options.

I needed a rack with the same requirements as you. I found online that a '95-'97 Geo Metro rack is rear steer and about 23.5" between pivots. I just go mine yesterday and haven't taken the boots off to get an accurate measurement yet. If I remember correctly, it has about 5in travel but can't remember the numbers of turns it took to get there. I'll post more details later after I measure it.
UPDATE: The Metro rack is 3.7 turns lock to lock with 5.5in of travel.

FYI
I found this list of steering racks over on a Datsun forum that helped me.
http://datsun1200.com/modules/mediawiki/index.php?title=Rack_and_Pinion_Steering

mjalaly wrote:
Any one know of how I can roll the tubes with out having it twist?! I think this tube is pretty much shot.

Well, in short, it's not easy. I ran into the same issue rolling my tubes. I welded on cross tubes across the end and had a person on each end try and hold them while running it through the dies (you can see this in my build log about 3/4 the way down on page 1). I also tried to make sure the 3 dies were all in plane, especially the top die to the two bottom ones. If they are off, it will induce twist. I think I shimmed the die left to right on the shafts to help. But in the end, I still had some slight twist in them but not enough to worry about.

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Last edited by JL1 on October 2, 2012, 7:57 am, edited 1 time in total.

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PostPosted: September 28, 2012, 10:32 am 
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JL1 wrote:
mjalaly wrote:
Can any one point me in the direction of a rear steer quick steering rack that is 22"-24"?? I am not finding too many options.

I needed a rack with the same requirements as you. I found online that a '95-'97 Geo Metro rack is rear steer and about 23.5" between pivots. I just go mine yesterday and haven't taken the boots off to get an accurate measurement yet. If I remember correctly, it has about 5in travel but can't remember the numbers of turns it took to get there. I'll post more details later after I measure it.

FYI
I found this list of steering racks over on a Datsun forum that helped me.
http://datsun1200.com/modules/mediawiki/index.php?title=Rack_and_Pinion_Steering

mjalaly wrote:
Any one know of how I can roll the tubes with out having it twist?! I think this tube is pretty much shot.

Well, in short, it's not easy. I ran into the same issue rolling my tubes. I welded on cross tubes across the end and had a person on each end try and hold them while running it through the dies (you can see this in my build log about 3/4 the way down on page 1). I also tried to make sure the 3 dies were all in plane, especially the top die to the two bottom ones. If they are off, it will induce twist. I think I shimmed the die left to right on the shafts to help. But in the end, I still had some slight twist in them but not enough to worry about.


Yeah let m know on the measurements and thanks for the great input.

Do you know what lock to lock on the rack would be??

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PostPosted: September 28, 2012, 11:49 am 
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mjalaly wrote:

Any one know of how I can roll the tubes with out having it twist?! I think this tube is pretty much shot.



Put a perpendicular tube through the end that a helper uses to keep the tube from twisting.


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PostPosted: September 28, 2012, 2:36 pm 
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JonW wrote:
mjalaly wrote:

Any one know of how I can roll the tubes with out having it twist?! I think this tube is pretty much shot.



Put a perpendicular tube through the end that a helper uses to keep the tube from twisting.


Is it not as simple as some guides? Does the tubing twist all on it's own without it being a slight feed error?

The only tube bending I've done has been commercially and all we used were some guides. But then we weren't bending the whole length, just sections.

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PostPosted: September 28, 2012, 7:49 pm 
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About tabs and control arms...
I'm building something similar to you and here's what I found.

*Start with a chassis with tabs welded on.
*Make a fixture to hold the uprights in their desired location.
*Place your heims with some tubenuts in the tabs and uprights.
*Fit tubing to make up the control arms with everything located in your 'jig'.

There's no reason the control arms can't vary a little and be specific to each corner, the suspension geometry can tolerate that.

This method allows you to get fancy with chassis tabs and not be forced to fit existing arms, my own attach to compund angle/radii\ which would have been impossible working with finished arms.

For jigs I used 2 lengths of 1/2 x 5" alum bars going accross the axle centerlines. They can be aligned with creative metrology, no need for a full body jig.


BTW, a Porsche 911 steering rack is about 22" and adjustable more or less by screwed in inner mounts, approx 1-2" range Iwould guess. Mine is set to 22" and the mounts seem to be just inward of mid range, I machined some pieces that allow heim joints instead of the rubber bush. You could also use a turbo rack that uses a spherical type inner mount.
The 911 rack is centered which has some benefits.


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