45 degree bending

[Chuck Pool]

Hi to all.
I have 360 brass 1/2 hard flat stock to bend. At present the dimensions of stock are 1/8 inch x 3/4 inch x 5.615 inches.

How can I place a precise 45 degree bend on each end of this flat stock? The bend will be 7/8 inch from the end.

I place 4 of above bent bars together to form a perfect square.

I tried a local shop with brake machines but they could not make a dead-on 45 degree bends.

I would like to bend one end at a time because there are different length requirements for other projects.

Thank you.
Chuck Pool
Cedar, MI

[Dukerc51]

I don't see why a press brake couldn't bend these darn near perfect. What I do on jobs like this is print a full scale template of the part and form to these. If your having dimensional problems I can show you how to trig out the B/D. It won't be half of the b/d of a 90.

[Chuck Pool]

Hi Dukerc51 and all:
Yes, please show me how you would trig out the B/D.
Thank you.
Chuck
Any other ideas out there?

[dumptruck]

If the bends are a little too much or too little, can they be re-bent to fit? Or is the bending in a brake a one-shot deal?

I'm just curious, I never worked a brake, but I find this post interesting.

When I was an aprentice, I did have an experience of trying to bend a 10deg "V" in several pieces of steel using a hydraulic press, "By eye" to fit a sample part. By pressing the center while the ends were supported on blocks. Then stop the press when you think it was 10degrees. HA !!!!It was a horrible and very sloppy way of doing things, But when in Rome and there's no proper equipment, GET A BIGGER HAMMER kind of shop. Oh, Those were the days my friends, those were the daze !!! I always and still do wonder just how a brake works, I think they are a neat deal, with bend allowances and radius compensations, I like Shop Mathematics , seeing math for real.

[Chuck Pool]

Dumptruck:
Hello. The bend should be a one shot deal. The material is very stiff and just about impossible for me to rebend for corrections. I am looking for a clean and "do-it-right" means of bending these small parts.
Thank you.
Any more ideas out there?
Chuck

[PhoenixMetal]

You can certainly do this in a press brake. Without question.

The way to do it is to first make the bend with the ram depth shallower than needed (making a 30 degree or so bend), and then gradually increase the ram depth little by little, re-hitting that same piece until you get the perfect 45 degrees. Increased ram depth = increased bend angle.

Once you get the ram depth right for that first part, your setting may or may not be good for all your subsequent bends (on a less rigid machine), since on that first part the machine was "helped out" by the reduced tonnage needed to make incremental depth bends on a part that was already mostly bent. So on your second fresh bend, you may need to adjust it a little deeper still. From this point on, the angle should be repeatable for all your parts.

I don't know why the shop you went to thought they weren't capable of this. Maybe their press brake was really crappy and had severe repeatablity issues and they knew they couldn't trust it. Or maybe they had it set "just right" for their existing work and didn't want to mess with its settings for a small job.

Also, you will obtain greater accuracy if you measure your angle using a simple protractor gauge (like this) rather than the 45 degree side of a combination T-square... Many shops with press brakes only ever make 90 degree bends, so they may not have a protractor. Since your material is quite thick, and needs to mate with other parts, decent accuracy is pretty important.

[Chuck Pool]

Hello PhoenixMetal:
Thank you for you information regarding bending brass bar stock.
This is helpful.
Thank you.
Chuck