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 Post subject: Roll pin strength
PostPosted: December 31, 2017, 9:37 am 
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Joined: February 28, 2009, 11:09 pm
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Location: Connersville, Indiana
Putting electric power steering into the Alpine. Yes, off topic car, but very generic problem.

Anyway, the installation has the power steering unit mounted between the steering box and steering wheel. The steering unit is adapted to the Alpine steering (3/4" tube with .150" wall) with a sleeve adapter. The adapter will be fitted over the tube and spring roll pinned into place. My problem is I have no idea about size of pin to use. It appears that most any size pin has the shear strength to do the job, but I'm wondering about shock loads which will go through the stock steering box and be absorbed by the electric steering unit.

Any insight into the problem is appreciated.

Bill


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 Post subject: Re: Roll pin strength
PostPosted: December 31, 2017, 10:01 am 
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Joined: January 2, 2009, 1:45 pm
Posts: 1173
Location: Halifax, Nova Scotia
What will your vehicle inspector (if any) say about a spring roll pin connector? We have used (spring) roll pin connectors for years to connect the tiller head to the aft steering post on DN ice-boats and compliance or outright wear and slop have always been issues. More recent designs have tended to replace the roll pin-based design with something more positive, or 'locking up' the joint by assembling with an epoxy/high density filler mix to unload the roll pin and use up all clearance. I am not sure I would be comfortable with an automotive steering application, but that is intuitive rather than an engineering opinion.


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 Post subject: Re: Roll pin strength
PostPosted: December 31, 2017, 12:33 pm 
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Location: Connersville, Indiana
Warren, thanks for input. Clearance is 2-3 thou. I would like for this to be removable. So the thought of cross pining comes to mind. Also, low temperature loctite to fill the gap.

Bill


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 Post subject: Re: Roll pin strength
PostPosted: December 31, 2017, 1:05 pm 
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Joined: January 31, 2008, 5:34 pm
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Location: SW Wes Consin
I might suggest a solid pin pressed in with snap rings for suspenders.


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 Post subject: Re: Roll pin strength
PostPosted: December 31, 2017, 1:06 pm 
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Joined: February 8, 2014, 10:47 pm
Posts: 492
Location: Cornholio OR "Where the magic happens"
No a pin (solid or rolled) is not a correct way to join a steering shaft.

Years ago, a boat I built steering parts for experienced a steering failure and killed a girl right in front of me.
The person who installed the parts did not use the recommended splined connections and a key sheared.
That girls mother screaming is burned forever into my memory.

You must use a spline or double D shaft to take the torque,
a set screw or pin can be used only to maintain engagement not for ANY torque load.

I get my steering parts from the wrecking yard or from someplace like https://www.speedwaymotors.com/Search?q ... g%20joints

I am a big fan of collapsable steering shafts as well. There are collapsable shafts available new and also Double D collapsable shafts at the wrecking yard.

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 Post subject: Re: Roll pin strength
PostPosted: December 31, 2017, 5:00 pm 
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Location: Carlsbad, California, USA
I don't have a real clear picture of exactly what you're trying to join, but I did get the idea of an adapter sleeve. Does one end go over (or inside) your 3/4" tube? Does one end have (or require) a spline on it?

Long story short, I went through some of the same design issues on my Locost setup your are doing here with your Alpine. The best advise I got for joining two components where you didn't had a "D" or Double D end or a spline, was two 1/4" bolts at right angles to each other where the edges of the drilled holes were at least 2 diameters apart (1/2" in the case of a 1/4" bolt).

I talked to 3 different steering component companies. The problem with using smooth shafts is that a high quality, all-around, TIG weld is the recommended way to fasten components. However, you can't weld commercial steering U-joints as you will damage the internal bearings, and alter the properties of the metal. Double drilling and bolting was the only method anyone would suggest as an alternative.

I finally went with the method that Wooward uses. They have splines (of several types) that will accept U-joints, and are meant to be fitted into the inside of your tubing and welded in place as follows:
Attachment:
File comment: Woodward weld-in spline method
Woodward-Spline-Weld-Detail.jpg
Woodward-Spline-Weld-Detail.jpg [ 41.37 KiB | Viewed 1002 times ]


I don't know if this helps or not because I'm not certain I am visualizing your intended setup, but I hope it helps.

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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 Post subject: Re: Roll pin strength
PostPosted: December 31, 2017, 8:35 pm 
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Joined: March 30, 2011, 7:18 am
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Location: central Arkansas
It has been a long time since I had a Woodward catalog; they weren't selling those spline bits then. Looks like a nice solution to the splined shaft problem.


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 Post subject: Re: Roll pin strength
PostPosted: December 31, 2017, 10:30 pm 
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Joined: February 28, 2009, 11:09 pm
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Location: Connersville, Indiana
Lonnie-S wrote:
I don't have a real clear picture of exactly what you're trying to join, but I did get the idea of an adapter sleeve. Does one end go over (or inside) your 3/4" tube? Does one end have (or require) a spline on it?

Long story short, I went through some of the same design issues on my Locost setup your are doing here with your Alpine. The best advise I got for joining two components where you didn't had a "D" or Double D end or a spline, was two 1/4" bolts at right angles to each other where the edges of the drilled holes were at least 2 diameters apart (1/2" in the case of a 1/4" bolt).

I talked to 3 different steering component companies. The problem with using smooth shafts is that a high quality, all-around, TIG weld is the recommended way to fasten components. However, you can't weld commercial steering U-joints as you will damage the internal bearings, and alter the properties of the metal. Double drilling and bolting was the only method anyone would suggest as an alternative.

I finally went with the method that Wooward uses. They have splines (of several types) that will accept U-joints, and are meant to be fitted into the inside of your tubing and welded in place as follows:
Attachment:
Woodward-Spline-Weld-Detail.jpg


I don't know if this helps or not because I'm not certain I am visualizing your intended setup, but I hope it helps.

Cheers,

Lonnie, you've pretty much got it. The adapter is two inches long. Female spline on one end, 3/4" smooth on the other. The steering shaft is 3/4" dia with .150" wall thickness. It would accommodate 1/4" bolts safely and they could be installed so they would be in full double shear. 1/4" hex socket capscrews have single shear strength of >5,000 lbs, so that would give a total of >20,000 pounds shear. Assembled with lock nuts, do you think that would be acceptable?

Bill


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 Post subject: Re: Roll pin strength
PostPosted: December 31, 2017, 10:44 pm 
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Location: Holden, Alberta, Canada
BBlue wrote:
The steering shaft is 3/4" dia with .150" wall thickness. It would accommodate 1/4" bolts safely and they could be installed so they would be in full double shear. 1/4" hex socket capscrews have single shear strength of >5,000 lbs, so that would give a total of >20,000 pounds shear. Assembled with lock nuts, do you think that would be acceptable?

Bill


Thats what I did with the exception of using two 3/16" AN aircraft bolts and nylok nuts drilled at 90* to each other spaced about 5/8" apart.

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 Post subject: Re: Roll pin strength
PostPosted: December 31, 2017, 11:41 pm 
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Location: Connersville, Indiana
horchoha wrote:
BBlue wrote:
The steering shaft is 3/4" dia with .150" wall thickness. It would accommodate 1/4" bolts safely and they could be installed so they would be in full double shear. 1/4" hex socket capscrews have single shear strength of >5,000 lbs, so that would give a total of >20,000 pounds shear. Assembled with lock nuts, do you think that would be acceptable?

Bill


Thats what I did with the exception of using two 3/16" AN aircraft bolts and nylok nuts drilled at 90* to each other spaced about 5/8" apart.

Perry, what is the shear strength of 3/16" AN bolts? 3/16" (#10) socket head cap screws have a single shear strength of 3060 lbs. A very brief search indicated the AN bolts do not have the shear strength of the cap screws. Mostly wondering if it would be worth my time to find them. I have lots of cap screws in my basement.

Bill


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 Post subject: Re: Roll pin strength
PostPosted: January 1, 2018, 10:20 am 
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Location: SW Wes Consin
AN screws would have the great advantage of being reliably sourced. Garden variety SHCS not so much.


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 Post subject: Re: Roll pin strength
PostPosted: January 1, 2018, 10:29 am 
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Joined: October 24, 2008, 2:13 pm
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Location: Carlsbad, California, USA
To answer your question, Bill, the double bolting would be a workable solution in my opinion. Perry has a lot of practical experience, so I think you could take that as a pretty good endorsement of the method.

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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 Post subject: Re: Roll pin strength
PostPosted: January 1, 2018, 10:40 pm 
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Location: Cornholio OR "Where the magic happens"
Even Karts have splined connections.

Unless the bolts are pressed in there will potentially be slop.

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 Post subject: Re: Roll pin strength
PostPosted: January 2, 2018, 2:34 pm 
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Location: Connersville, Indiana
Bent Wrench wrote:
Even Karts have splined connections.

Unless the bolts are pressed in there will potentially be slop.

That takes us back to roll pins. :)

If slop is the issue, how about using a sleeve retaining material in association with bolts? Is the problem with not using splines or double D fittings failure due to component failure, or failure due to improper assembly or parts substitution? Today, the proper solution seems to be tied to TIG welding. What was used prior to this technology?

Bill


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 Post subject: Re: Roll pin strength
PostPosted: January 2, 2018, 11:19 pm 
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Joined: March 30, 2011, 7:18 am
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Location: central Arkansas
A common solution was the flexible coupler. A piece of what looked like used car tire was sandwiched between two bars 90 degrees apart. The bars were attached to the shafts via splines, via an offset bolt and slot, keyed, or simply welded on. Remove two opposing bolts from through the coupler to disconnect. Simple, cheap, and it was the standard way of hooking up steering bits for many decades.


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