Tight radius bending

How wide? For a one or two off try to press a form into a die using a bench vice?

"Den" fired this volley in news:48035d14$0$30919$ snipped-for-privacy@per-qv1-newsreader-01.iinet.net.au:

The standard method in the 'ordinary' sheet metal fab is to use radiusing noses on your fingers, and set the platen away from the center of radius by the radius of the noses, plus the thickness of the metal. Polished parts make a big difference in quality of the finished bend.

LLoyd

A slip roll can only roll as small as the roller size, plus some springback. And it cannot generally make a U shaped piece with straight sides, the entire piece you feed in will roll into a circle. It is possible to insert the sheet with the rolls backed off and then tighten them down gradually when you are at the bend point, then you roll back and forth. I don't know if it would work for such a tight bend.

At work we had finger brakes with radiused noses, but not as large a radius as you want. It would require a brake with an articulated bar. And they will not bend a 180 anyway.

I think you need a press brake with a deep female die and a round-nose 'pusher'.

This sounds like a press brake job. You don't give the length of the bend. Commercial press brakes can do huge work, but a 6" vise can do small items in thin stock. Harbor freight had a magnetic press brake adapter for a 6" vise. The blades that come with it are too sharp. but a piece of steel rod of the appropriate diameter can be made to work by welding it to form an edge on rectangular bar stock. Or the bar stock can be ground to suit. The V bottom will work OK for an air bend like this. If the vise is too small, appropriate dies can be made for a hydraulic or an arbor press. I looked at the HF web site for an example, but didn't find it. Here is one from Grizzly:

Feel free to email me if you need more info. I used to run a 12' press brake.

Give this a try on some practice material;

Bend one thin strip well past a right angle, then back up the fingers by its thickness and bend a second one over it, then repeat etc. I've only done this with two strips plus the work so I don't know how far you can go. This also works on the vertical press brake on a 3-in-1 combo machine but the narrow lower die limits the maximum radius.

Jim Wilkins

If you're doing enough to justify the effort, something like this would work. I used dowel pins for their hardness and good surface finish, but was bending Inconel wire with that particular jig. Mild steel would last a long time working aluminum.