Clevis Pin Size 1

[stewartcs]

This is not a topic I have any experience in so I'm hoping someone could give me a book reference as to the theory behind the design of these or something along those lines.

I need to determine whether or not a pin of 5.00" diameter can be used in a hole designed for a 5.25" diameter pin.

I imagine all I would need to check is for contact surface deformation, pin bending and shearing stesses...correct?

Would the extra clearance caused any problems?

Thanks...

 

[40818]

A quick answer is yes. There will be a reason that the bolt is 5.25" diameter. Source out the original calcs before proceeding.
There are many reasons why what your proposing is plain dangerous.

 

[stewartcs]

I would imagine the pin is 5.25" so as to support the size of original load without exceeding the yield point of the pin or shearing the pin.

Is there something else that should be checked for in relation to the clearance of the proposed smaller pin? Or, is it just a matter of the previously mentioned items?

 

[boo1]

Spotts gives the elastic analysis equation for max compressive contact stress (Po) for two different radius cylinders (in your case R1 smaller 2.5" pin and R2 larger hole), P1 load per axial inch on cylinder:

Po=0.591*Sqrt[{(P1*E1*E2)/(E1+E2)}*(1/R1-1/R2)]

Note stresses can be very high due to the small contact area. To reduce the stress reduve the clearance between the two bodies.

 

[GregLocock]

Also, dynamically, you will get hammering, as teh clearance allows a relative velocity to build up between the two parts.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[hydtools]

What are the parts that are being pinned? What is the length of engagemnt? Is the joint a static joint?

Ted

 

[vc66]

My first question is... why can't you put a 5.25" in? Beyond that, knowing whether joint is static or dynamic would be a help.

I would say that, at first glance, I would be wary to use a pin .25" less in Ø, but it all depends on the variables involved.

Good Luck

Victor

Mechanical Engineer/Consultant
Medical Devices
"When I am working on a problem, I do not think of beauty, but when I've finished, if the solution is not beautiful, I know it is wrong."

- R. Buckminster Fuller

 

[stewartcs]

The clevis and pin are under contant tension, but the magnitude does change slightly. Essentially it is a static load with a maximum value high enough to allow for reasonable dynamics.

 

[civilperson]

If the pin can not change, perhaps a modification of the hole size is posible. Weld to fill the outside diameter and then use reamer or drill to produce correct size hole.

 

[hydtools]

Use seamless or dom steel tube to make a bushing.

Ted