Narrow U-shape bending

[ruddermode]

I'm new to the etched kit building game, so I'm probably missing something obvious!

 

How do I bend etched brass into a narrow U-shape? I have a set of bending bars, but that's only good for one side - when bending the second side the first comes into contact with the bar very quickly with most of the bend still to do.

 

One idea that came to mind was to start the bend off in the bars, then finish it between two steel rulers held in the vice (pity I've only got the one steel ruler!). Any other better ideas?

[craigwelsh]

Use a metal ruler screwed down to a thick surface and slide a blade from a stanley knife under it to start the bend.

 

Two rulers in a vice is a bit tricky, you can line them up by taping together but the part tends to fall out or not sit level. The pressure is normally focussed too narrow as well.

 

Both of the above methods have been tried by me on metal solebars 120mm long and 3.33mm high to get around spending £80+ on a Hold n Fold (i'd buy the expensive one for coaches)!

[Kenton]

a Hold n Fold

I was going to suggest - but then I thought - I don't use it for small U folds where it has the same issue as bending bars.

 

What I use is my ownn version of bending bars - two strips of 2.5mm steel plate that are bolted together. but even these are not much use when the channel is really small and too small to grip in this vice.

 

I then cheat and buy brass channel from Finney's or Eileens. (not a perfect solution but less stressful)

[Enterprisingwestern]

You will never bend U channel in bending bars, it needs to be formed round a suitable diameter piece of bar/drill shank or whatever.

[Boris]

As the man says, use a former of some description. You will also find running either a triangular file or a slightly blunt knife blade down the inside of the fold line until you start seeing feint marks on the opposite side of the piece makes the folds much easier to make.

[Kenton]

You will never bend U channel in bending bars, it needs to be formed round a suitable diameter piece of bar/drill shank or whatever.

Conventional bars - you are correct, but if the thickness of the "bar" is the same or less than the channel it can be done.

 

Of course there are other methods

for example starting both side bends then finishing between the jaws of a vice

 

and,

You could build from 2 lengths of L angle strip and solder them together

 

or even,

cut/snap off one side bend the firs L, then edge solder the snapped off strip.

 

But the easiest (and least stressful) remains the buy it approach.

[ruddermode]

I can see how a drill would be useful for round-bottomed U-shapes - thanks for the tip!

 

I tried a ruler clamped to the table for square bends last night and was quite pleased with the results. Squareness had to be assessed by eye but I'm not sure there is any other way of doing that (a square on the outside would work in theory, but very small sides on the piece of metal make that hard to judge).

 

It took more than two hours to do a total of four bends in a couple of buffer beams and solder them to the wagon body, at least the solder joints are starting to look a little bit tidier than before...

[craigwelsh]

 

But the easiest (and least stressful) remains the buy it approach.

If you can find some 3.33mm channel to do 10" solebars then great but I haven't so far. 9" (3mm) is a bit easier.

[R A Watson]

If you can find some 3.33mm channel to do 10" solebars then great but I haven't so far. 9" (3mm) is a bit easier.

 

Take the "traditional English" approach 1/8 inch is equal to 3.3mm and may be easier to find!