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Old 03-14-2016, 09:00 PM
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MetalShaper of the month Feb.-11, July - 2018
 
Join Date: Mar 2010
Location: Leonardtown, MD
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Had a question about placement of the thinning groove, so I thought I'd post the results of the test sample...




Quote:
Originally Posted by WoodsTruck
Question about the use of your tipping die for bending a straight line.


What would happen if you made the divot on the back side of the bend instead of the front? I realize you are referring to this as "thinning" the metal, but aren't you actually forging it in a sense since you aren't actually removing metal but compacting it primarily? To my inexperience it would seem that a tight bend could be made without the resulting trough if the tipping die was used on the backside of the bend.


Fantastic work though, wish I had half the knowledge and tools to do that stuff. I'm a graduate of the BFH school.


Here's the test from tonight. The 16 ga thickness measured out to about .057, at the "thinning" groove it was .053, so we lost about .004 in thickness, or less than 10%. Put the thinning groove on the outside for this bend, it tended to stretch the deformity back out again where it looks like it could be more readily cleaned up with a file..











So where the bending process allowed the groove to stretch back out....







...it also gave us a wider radius than when the thinning was placed on the inside of the bend...







So I'd say to use placement based on if a tighter radius is needed or whether you need it dressed out. Given our original intent was a tighter/sharper radius, I'd place the thinning inside the bend to support that..
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Last edited by MP&C; 03-15-2016 at 07:56 AM.
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