# Thread: Beam Deflection

1. ## Beam Deflection

I am planning on making a press that will consist of a steel tube for a 'spine' with the cylinder mount and the center of the work support about 6 inches out from the spine. The picture shows a sketch of the spine lying down.

What deflection can I expect at the midpoint with a force of 10,000 lb as shown using 1/4" wall 3" x 6" tube?

2. ## Calculating Beam Deflections

Anybody that went through a mechanical engineerng class will have formulas for the problem and lots of supporting thoughs on beam support, but the easiest way to do the problem today is google "beamboy" then download the freeware. With beamboy you just have to realize that your beam is simply supported and torque loaded.

Tom

3. Hi Geof

Please ignore this calculation as the deflection is wrong and I have removed it. Thanks to kevin for pointing it out

I have not checked the elastic limit to see if the beam becomes permanently bent. For a given weight of steel section an "I" section would be a more normal configuration in a deeper section than 6". Any structural steel supplier should have deflection information for both point loaded and distributed loaded beams simply supported at each end. Otherwise calculate using the full steel spec. There is often safety factors to be consideration with these sort of forces.

Regards - Pat

4. Pat I think you should run your numbers again or that was a typo.175 inches might be what you meant

5. Hi Geof

Displacement -3.380942e-02 inches

Thanks to Kevin Swan pointing out that I had boobed. I think this is now the sort of deflection you would get. I must have failed to up date the material to steel from the light weight alloy I am used to.

Regards - Pat

6. Originally Posted by wildwestpat
......-3.380942e-02 inches........
Thanks Pat. That deflection sounds quite acceptable. Actually what I showed in the sketch is more or less the extreme conditions. Probably the press will be used at about 5000lbs with a separation of less than 48 inches between the two ends. Also the tube will be reinforced by a length of 3/4" x 6" flat bar that will be machined to provide ways to adjust the operating length of the press. From your results I think I can expect that the finished device will have negligible deflection under its most common working conditions with negligible being less than 0.01". The purpose of it is to push aluminum fittings onto the ends of stainless steel tube for a product we make.

### About CNCzone.com

We are the largest and most active discussion forum from DIY CNC Machines to the Cad/Cam software to run them. The site is 100% free to join and use, so join today!

### Follow us on

Search Engine Friendly URLs by vBSEO ©2011, Crawlability, Inc.