Bending sheet metal

[Metriccar]

Right now I have a bottle jack shop press, with a brake in it for bending metal 90 degrees.

I see of no realistic way to, say, bend metal 45 degrees accurately and consistently.

What kind of tool would be best for this? I can bend metal 90 degrees all day long.

Are box pan brakes reliable in that regard? Or hydraulic press brakes?

[little blue choo]

Metriccar, I use a box brake from Grizzly and a magnetic angle gauge I purchased from Harbor Freight for less than $5.00. It's the best $5 I ever spent. I'm including a link to it on their website.
http://www.harborfreight.com/dial-gauge ... 34214.html

Hop this helps
Rick

[Dana gear]

We use apron and box and pan brakes all the time with very good results. we have shop/factory built back stops and graduated degree bending systems.
Sometimes we make a sacrifice bend to test for the results we want then set the stops and get great repeat ably after that on the mechanicals.
You could fabricate an adjustable stop on each end of your die to achieve the bend angle repeat ably you want with a bottle jack press your using.
Anything that would stop your die travel at the point of degree you are trying to achieve for the metal thickness you are using.
Crude yes, but it could work.
As for your question about the forming accuracy of hydraulic press brakes the answer is simple, we have both mechanical and hydraulic press brakes here. Set up correctly both the mechanical and hydraulic press brakes can form dead on

[Gamelord]

Could you build a new jig for your hydraulic press that only bends to 45'. Plasma cut out some shapes that are at 45 degrees (like a bow tie but flat on the bottom), weld them together with a flat bar across the top and then do the reverse for the top part. Slide the jig into the press and go for it.

[flimmy]

Don't forget that you may need to over bend the material to get the 45deg that you want because the steel may want to spring back.

[KIDTech]

I bent quarter panels for a Challenger this weekend using a press brake kit from SWAG Offroad. They turned out great and had four compound bends in them.

[rwskinner]

If your using a brake like one from swag, you can cut some spacers or stops to stop you in the same place all the time. After some minor adjusting, you just pump your jack down to the stops then release. That's what I do for my radius brake and I have perfect bends every time.

Mine is just tubing spacers that go on the alignment rods. Then the top punch comes down until it hits the spacer on both sides.
Start with the spacers a tad long, then trim each side a little until you get the perfect bend. You can mark them and save them for the same setup later.

[KIDTech]

If your using a brake like one from swag, you can cut some spacers or stops to stop you in the same place all the time. After some minor adjusting, you just pump your jack down to the stops then release. That's what I do for my radius brake and I have perfect bends every time.

Mine is just tubing spacers that go on the alignment rods. Then the top punch comes down until it hits the spacer on both sides.
Start with the spacers a tad long, then trim each side a little until you get the perfect bend. You can mark them and save them for the same setup later.

Good point, that's great for when you have a part you may make quite a bit or a few a year that have a unique degree. Find the angle, measure, cut your spacer and now you have repeat-ability.

[rwskinner]

Depending on the style of your press brake, adjustable stops would work well. Once you got the angle perfect, measure the stop and record the value.
Something as simple as a coupling Nut and bolt with lock nut. My Radius brake doesn't have return springs. The Radius punch is secured to the hydraulic Ram so when the ram retracts it lifts the punch up. This allows me to drop spacer tubes on the alignment rods and not worry about the springs being in the way.