Bending Davit Arms
Bending Davit Arms
(OP)
We wish to construct a press that will allow us to cold bend A36 solid round bar 90 degrees for use in davit arms. In sizing the press, we need to know how large of a hydraulic ram to use. There are a lot of tube and sheet bending formulas out there,but little on solid rounds. Any suggestions where to find formulas for force required and springback?





RE: Bending Davit Arms
RE: Bending Davit Arms
RE: Bending Davit Arms
The problem is the difference between pipe O.D. and solid bar O.D. We current 'farm out' the bending of 5/8" to 2.00" solid round bar and we wish to build a press to do it ourselves. Nomimal pipe O.D. won't work.
Deanc:
We currently have the bar cold bent and it works well for our application. Heating would make life easier in some respects, but it's another step and cost we wish to avoid, and cold bending seems to work with the product we are receiving.
I guess I could get more specific: how much hydraulic force is required to cold bend a 2.00" diameter solid round bar 90 degrees with a 4.00" inside radius? It is doable and our supplier doesn't want to give up any information, naturally.
RE: Bending Davit Arms
bending? I would think a coil spring
manufacturer could give you some formulas
from their experience. How many pieces
are you making?
RE: Bending Davit Arms
RE: Bending Davit Arms
Where the first moment of area is the integral of dA*z
where dA is a small area and z is its distance from the bend axis.
Sorry I haven't got time to work it out, but it would be roughly 3/4*d/4*d*d/2*2 or a bit less
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Bending Davit Arms
500 ton press should be adequate if you have a 12" spread on the bottom. Once you get your stroke set your off and running. Be prepared to scrap a few for set up.
Make sure you build it strong and anchor it well so it does not take off on you.
If you have a good press brake operator who has done AR plate....they should be able to set this up.
Another option would be a "wrap around" such as an Erhle Former. Moving table which wraps the part around a fixed die. Not many of these around,job shops have most of them.
Note: If I did not have the equipment or the right people I would still form it hot.