Need Help With A Forming/bending Die

http://www.cpmfab.com/img_extras/Betenbender_gooseneck.jpg
The above is a goose neck top die. The bottom die should be a v die as in the above proto tek link. bottom the gooseneck into a 90 degree v and the angle will not spring back. The gooseneck allows the ear, so to speak, to bend. Then slide the piece in for the second bend. The ear from the first bend will contact the back of the gooseneck. The ear cannot be larger than the middle measurement. ie, You can make a channel 1x1x1 or 2x2x2 but cannot make a piece 2x1x2. To do that requires a die spacer so that the ear is free to come around into an empty space above the top die.
Chuck
 
Yes Chuck this is what I meant by off set. I may up and build a couple like that just so I have them when the time comes that I need them.

kd, yes that may be the best way but I don't see that happening any time soon. Maybe in 10 years when I retire and move to a place with more shop space. It would have to be pretty stout to bend 11g.
Mark
 
Here is a quick sketch of what I meant. Hopefully it is pretty clear what is what. The work is clamped between the two flat bars on your press, the piano wire in in the corner of the channel, and the die is pressing on the top.
bend.jpg
 
Got you now. Yes I see how I could make that work. Thanks I may just play with this a bit for future use.
Mark
 
OK Guys I got back to the shop some lately. I have been playing with an idea based on all the input from you guys. My thought is that by tapering the top die in toward the top to provide relief for over bend. But since I can not cause the sides to be flexed passed 90 deg. to adjust for spring back my plan is to pocket the bottom face of the top die in such a way as to allow the center of the part to flex up. the final thing is to use some thing as a shim in the center of the bottom die to force the center of the part upward. By doing this I hope to add just enough additional flex to compensate for the spring back.

Here is my rough made top die I finished today so you can see what I did such a bad job explaining.20150910_205214.jpg
 
If that works it's pure genius. You'll still have the springback but forcing the center of the bottom up causes the angles to be just over 90º.

Interested to see if it works.
 
I am still trying to get back in the shop and finish this up. Yes you are correct on the spring back. I'm hoping for genius, even if it is only close I will be happy. I am testing on some 11 gauge I have laying around.
Mark
 
If I looked at the right chart 11 gage is 1/8 of inch thick. How much spring back are you getting? I am thinking if you heated up the steel just before bending if that would relieve the stresses in the bends reducing the spring back. I don't recall bending wide sheets of 1/8" material. I have bent 1/8" HRS bar stock.

Good luck with your project.
 
Yes bill I think Heating it first may help. but I am now just sort of trying to work this out after I made the part. The spring back was in the order of .0312" over 1.25" on each side of the u shaped bracket. The bend is 6" long.

The end fix to the original part was to heat the corners while pinching it in the bench vise.

This is more one of them things of where did I go wrong and how do I fix it? And was there a better way?
Mark
 
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