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Uni ball cups

rdc

- users no longer part of the rdc family -
My brother and I just welded together one of the lower arms for his truck but when we looked at the finished product we realized the uni ball cup was snap ring side up. We meant to put the snap ring grooved side down but a momentary lack of concentration now leaves me with the question: Will it be ok to run it with the snap ring on top or should it always be on the bottom?
 

Flea

Well-Known Member
I would imagine that it would be strong enough. you have to press the uniballs in anyway so they pretty much stay where they are. the snap rings are pretty thick and look pretty strong but???? we need some expert advice on this one

GOD BLESS AMERICA! and hopefully my poor truck too.
 

BradM

Well-Known Member
I suggest y'all pay a little more attention to your work in the future. What is your application? How hard do you intend to drive the truck? It would probably be fine for everyday use and occasional weekend fun in the desert but it you plan to drive like Dan Vance, cut it off and get a new cup. What size uniball are you using. I don't have one in front of me but from memory, I believe a 1" ID uniball has a bearing OD of 2.125". Industrial Retaining Ring quotes a 2.125 Internal 3000 series snap ring to have a static thrust load capacity of 23400 lbs to shear the ring and 11300 lbs to the failure point of the groove. More than adequate except under extreme conditions.

Also, the spherical bearing should not be a pressed fit into the cup. If you have distortion in the cup from welding, you should bore it or at least clean up the tight spots with a sanding cone. The bearing life will be adversely affected by an improper fit.



"The only source of knowledge is experience." - Albert Einstein
 

vwguy

Well-Known Member
i used to work in a buggy shop and of the long travel a armed cars i would say half of them have the snap rings on the top but then again its a buggy not a truck but i would say it would be good for now

how ironic is it that most people slow down for speed bumps yet almost all of us here im sure pin it
 

rdc

- users no longer part of the rdc family -
Well, considering this is the first complete truck that my brother and I have built (started with a frame and parts of the cab) I am pretty stoked that this is the only f'up we've had. The arm is 24" pivot to center of the uni, we are using an 1" ID uni and the cup has not warped (although it looks like it is all for not). The truck is a toyota and we are using a 22re, it is not going to be street legal just a prerunner (not racing it) that will see action only a couple times per month. I think I will cut out the cup and put a new one in right side up. I'd hate to be stranded miles from camp because of something I could have taken a little more time to fix when I had the chance.
 

Mikey

Well-Known Member
BradM, how tight of a fit should there be between the ball and the cup. Should it fall out when the snap ring is removed?

Moto, is your life worth $21.75 for a new cup?
 

FABRICATOR

Well-Known Member
Moto,
There are 3 things to consider here:

1) The unit will work fine, until the snap ring pops out,

2) The uniball should go in by hand or very light taping,

3) If you're going to fabricate anything, you need to be ready, willing, and able to re-make that part.

I re-make parts fairly often and I'm sure even BradM has too...Some are complete screwups, others are quality control, and some are the realization that it could have been made better or improved. The peace of mind from doing it again right is well worth it.

<font color=orange>The best ideas are the ones that look obvious to the casual observer.</font color=orange>
 

BradM

Well-Known Member
It seems that every manufacturer of spherical plain bearings has their own specifications for the housing bore. For a bearing that size, the average is from 0.0002 to 0.0008 under sized for a slight pressed fit. That takes into account that the tolerance for the OD of the bearing race is +0.0000/-0.0006. Thus a slight press fit is acceptable if the cup is machined round. The problem with a press fit due to distortion of the cup is that it does not apply an even load distribution to the bearing race. In that case, you would be better off to have a "slip fit" or a "tight fit". I bet the cup "as machined" from HM or someone else is at least +0.0005/0.0010 over the OD of the outer race.



"The only source of knowledge is experience." - Albert Einstein
 

BradM

Well-Known Member
You could always keep those for spares and build another set for the truck.

And yeah - I have made my share of parts more than once. The key is to hopefully learn from it so it only happens once.



"The only source of knowledge is experience." - Albert Einstein
 

rdc

- users no longer part of the rdc family -
Ya Mikey, my life is worth $21.75 but add in the 8% sales tax and, I don't know.

I am going to cut out the cup and replace it but oh well, I bought 6 cups just incase something like this happened. The good thing is I won't be putting any upside down again. I just wish I had noticed the mistake when the arm was just tacked together and not after it was all welded. Thanks for the help every one.
 

Dave_G

Well-Known Member
Re: I bet the cup "as machined" from HM or someone else is at least +0.0005/0.0010 over the OD of the outer race.

And probably out of round in three places where the three jaw chuck clamped it. ;-) You gotta bore that stuff after it's been welded or your just fooling yourself. Stick a dial bore gauge in there after welding it and you'll see how bad it is. I guarantee it!

Dave

"I know it all, but I can't remember most of it..."
 

Dave_G

Well-Known Member
Re: how would one go about boring it out back to spec?

You leave the cup undersized when you make it, weld it in the structure, set the a-arms up in the mill and bore it out to finished size. We've done that for a lot of TT's over the years. Works every time....

Dave

"I know it all, but I can't remember most of it..."
 

Dave_G

Well-Known Member
Re: Do you make your own cups?

Jason,
Yes. Whe have the technology. ;-)

Best,
Dave

"I know it all, but I can't remember most of it..."
 

DPpatrol

Well-Known Member
Dave,
I just read your profile and realized that you work for a machining company, so ya, it would make sense that you have the ability to machine your own cups (very cool). But how would you reccomend the average garage fabricator go about getting uniball cups back in spec after welding?

jason
 

Dave_G

Well-Known Member
Re: ). But how would you reccomend the average garage fabricator go about getting uniball cups back in spec after welding?

Jason,
One way is to insert a solid piece of steel that has been machined on the O.D. that simulates the fit of the Uni ball. If the Uni ball is a standard size like 2.000 you can use a cut piece of 2" cold finished mild steel bar stock. Press it into the cup before welding using high temp antiseize and this will help hold the cup round while welding. Then when your done welding just press the slug out after things cool. It's certainly not the best way to do this but you stand a better chance of keeping things round than doing nothing at all.

Best,
Dave

"I know it all, but I can't remember most of it..."
 
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