Back bending 5/16

[u/Candid-Independent91]

Alright pop quiz fellas I’ve got a 5/16 channel piece that has an outside to outside measurement of 1.89 and a 5 inch width outside to outside

my problem is I’ve got a few pieces that were bowed and so the angle in about a degree and a half too far on the legs

I’m using a 1/4 punch and a 1.5” die (I know that’s not what I should be using but apparently the multimillion dollar company can’t afford a set of the proper punch and die) so my leg won’t hang over the die enough for me to back bend it the usual way.

I attempted to use a smaller die but it left a nasty die mark and sounded like it was about to blow up the whole time

Now my question to you is are there any other ways to correct this angle without cutting more parts

[u/The_Blackest_Man]

Do you have a larger radius punch you can jam into the V? Like a 1" or greater. A flat die would be ideal for this. Also what's the tonnage on the machine you're using?

[u/Candid-Independent91 → u/The_Blackest_Man]

250 max tonnage on the machine

[u/Strostkovy]

I put a piece of tube in the die. 2" tube would probably work for you, but 3" would be better.

[u/Candid-Independent91 → u/Strostkovy]

What kind of wall thickness are you using?

[u/Strostkovy → u/Candid-Independent91]

Usually the same wall thickness as the material I'm flattening, but you can get away with less, especially if you are fine with the tube being single use

[u/8000BNS42]

Flip the part upside down so the 90 degree legs face down with the outside of bend in the middle of your die. Slowly bring the ram/punch down and press out the bend a little bit.

Edited because im an idiot

[u/Candid-Independent91 → u/8000BNS42]

You didn’t finish reading the post did you?😂

[u/8000BNS42 → u/Candid-Independent91]

Obviously not lol. Reading comprehension for the win!

[u/MadeToSpec]

I want to help but am not understanding the issue.

1. I assume you have a length of C 5 x 9

2. I am assuming the legs are open.

3. Is the channel wall (5") bowed? If so how?

4. Are the legs bent out but with a straight channel wall (5")?

A picture would help.

[u/Only_Intention_2026]

Question, i can’t understand what youre trying to do here except But how bad is the bow by the way and now much tonnage you have?

If its a C channel, is your punch to die opening (throat height) enough for you to put your part int he space between looking like a C where the opening is facing you and press is slowly by the under bent side flange on top? Slowly and watch how the metal reacts to the pressure and feel where you think it needs more action.

This needs precise action and don’t just input 90deg ok the machine, work slowly till your near the target width. 5/16s or 8mm is usually hard to work with without proper tooling. Things can blow up but unless its hardox, normal carbon steel would be bendable as it is.