I'd make a simple jig from a rectangular metal block with a fence to define the gap. Start at one end and work your way round clamping as appropriate to stop it moving. At that size the simple "caulk gun" style squeeze clamps should hold OK.

Radius the corners as apprpriate for the metal thickness. Zeus book has the sizes. Sharp bends in stainless is hard.

If the block is simple rectangle with parallel sides the shape ill be underbent. Either use a second jig with suitably angled sides or a piece of angle iron arranged with the upstand in the middle to form the final bend around. Could get fancy and hollow out the jig to overbend so it comes out straight. Nice when you get it right but may take some experimentation.

Making the bends would be a job for my small nylon faced Thor dead blow hammer I think. In stainless steel thats a classic "get someone else to do it" job!

Clive

Edited By Clive Foster on 31/08/2022 08:55:54

Posted by Die Hardenedbedway on 31/08/2022 08:38:55:

There are bench top / vice mounted benders for metal strip (used for ornamental metalwork).

This sort of thing (not necessarily these specific machines though):

Micromark Universal Bender

Metalcraft RBR Tool

(Many examples of home made ones on Youtube too).

Edited By Andy_G on 31/08/2022 09:44:33

As Jason shows simple pressing works pretty well for curves and shallower bends in less stiff materials such as alloy, mild steel, copper and softer brasses. Hard brass tends to crack when you are least expecting it.

Not so easy with stainless steel which has serious spring back issues. Less of a problem with shallower bends and curves but you still need to allow for it. Found that out the hard way when I tested tooling somewhat similar to Jasons second picture with some ordinary steel rod before switching to (expensive) stainless for the real thing. Had to tighten up all the bends by hand afterwards.

Sharp bends can be a nightmare. Even the professionals often resort to experimentation. Even when you have got things sorted stainless also has a nasty habit of changing its mind on you half way through the job needing "some adjustment" for the last 50!

If pressing you are probably best off making each bend individually with a relatively thin forcing blade having a suitable radius tip working into an open ended Vee former. Nice radius on the sides of the opening too so the bent material can push through without marking so it over bends enough to cancel the spring back. Not the fastest way of working but once sorted with suitable end stops to define push distance its effective.

Ordinary hand lever bench press will do just fine in your size.

For obvious geometrical reasons the Vee former has to move rather than the blade so its all a bit inside out. Sort of thing that can seriously mess with your head if you don't think it through carefully. Who once made a bending tooling set up that worked just fine except for extracting the finished job! Yup. Moi. Ooopsi, red faced variety.

Hard bit is devising a set up that aligns the stock material correctly so the bends are in the right place and the thing doesn't come out twisted. Radius end on the pusher means you can't align on a scribed line as you do when using the magnetically held "Vee and sharp pusher" devices in a vice. Very effective on the right jobs. So glad I bought mine. Even with those it can be hard not to end up with a twist in the bend. Like what I've been known to do!

If you had enough to do to make serious tooling up be worth the effort it might make sense to refine a basic inside block former by adding lever operated rollers to form each corner from the outside to work quickly and accurately. Not as easy as it sounds because the lever and roller assembly has to be made so that it can be taken off to remove the finished part. Forked end and pull the spindle I guess.

Clive

PS I hate bending to accurate shapes, mostly 'cos its usually onsesy – twosey so job is done before the method gets sorted.

Edited By Clive Foster on 31/08/2022 16:12:50

Such a basically U shaped can be made in a box and pan press brake, although it might be necessary to be remove the work sideways at the end, or depending up the size of the work and the folder, it might be possible to remove the work after the final bend, by removing the upper blade to allow the work to be withdrawn..

With a BIG press brake it could be done using a block to hold own the outer ends while the final bend is applled.

Failing that, make the two outer bends, and then the outer ones will have to be made around a former.

Howard

A very small thing to add to the good advice above: stainless bends slightly differently depending on whether it is bent along the rolling direction of the sheet or across it.

If you are to have the blanks laser cut, it might save a lot of heartache to insist that all parts are oriented the same on the sheet (as the laser cutter's nesting software might try to rotate some parts).