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Bending Brass


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Guys,

A quick question, that im hoping somebody may be able to assist with.  Im looking to bend some thin (3/16th) brass that is around 10mm wide.  Im more use to working in wood than brass, so a little out of my depth with this.

 

I need to create four strips, each of which has two 'U' shapes bent into them - the depth of the 'U' been around 6mm - so not massive.  I have thought (and tried) bending with a pair of pliers, but am having difficult getting the 'U' to come the right size, both in width and depth.  Having done two, and realised they are both a mm or two out, I'd realised I need to create some kind of jig that the brass can be laid in and then the top and bottom jigs clamped together to create the bends in the right place.

 

The question is, can anyone suggest what to make the jig out of? Wood would be too soft I feel.  Im happy to CAD design and have something laser cut, but that seems overkill - although im conscious both top and bottom part of the jig need to be almost identical for it work.

 

Any thoughts? Im assuming for scratch builders this is probably a regular task??

 

Richie

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You will need to anneal the brass first. this is heating it to cherry red and letting it cool slowly. This will make it easier to bend and stop it cracking. May need annealing more than once as it will work harden. Use vice pliers and hammer to form around a drill shank slightly smaller than required.

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I think you'd have a job bending 3/16" brass around a 6mm drill.  I had a similar job to make U shaped pipe clamps for the purpose of securing the vacuum pipes on a 7 1/4" g. loco. This was achieved by making male/female dies out of steel.  To form the clamps a strip of annealed brass is squeezed between the dies, as you suggested, in a large vice.  Although I only needed 2 at least they were both identical.  Best of luck.

Ray.

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Mark the centre line of the brass strip, scriber a line down it and use the edge of a square needle file to put in a groove. Don't file too far, then the brass will bend easily along the line.

Must admit I haven't done it with 4.5mm thick strip, but it works in thinner pieces, so no reason to suspect it won't.

 

Mike.

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Thanks guys,

 

I'll have a go with some of these ideas.

 

You will need to anneal the brass first. this is heating it to cherry red and letting it cool slowly. This will make it easier to bend and stop it cracking. May need annealing more than once as it will work harden. Use vice pliers and hammer to form around a drill shank slightly smaller than required.

 

Do you just heat it with a miniature blow torch?  Presumably let it cool before trying to bend it!

 

I think you'd have a job bending 3/16" brass around a 6mm drill.  I had a similar job to make U shaped pipe clamps for the purpose of securing the vacuum pipes on a 7 1/4" g. loco. This was achieved by making male/female dies out of steel.  To form the clamps a strip of annealed brass is squeezed between the dies, as you suggested, in a large vice.  Although I only needed 2 at least they were both identical.  Best of luck.

Ray.

 

 

A m/f die was at the back of my mind when I posed the question - is it just a cut and file job, or is there a way of making dies?  Never done it before, im conscious that the M and F need to be a decent fit to get the right shape.  A die is probably the best idea seen as I've four strips for this project, and potentially another four later on!  Any pointers or heads up on where I can find online tutorials would be welcome.  I'll go have a google tho!

 

Thanks everyone.

 

Richie

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Richie, for the female die I took a small rectangle of 1/2" plate and drilled a hole the same size as the O.D . of the finished bracket near to one edge. I then hacksawed and filed this to the required U shape and took off the sharp corners.  The male die has to be one thickness smaller than the female all around but the same shape. I silver soldered the male die to a piece of 1/8" plate the same size/shape as the open edge of the female die to make it easier to hold in line in the vice before squeezing.  I hope this makes sense - if not I'll take a photo tomorrow.

Cheers,

Ray.

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Richie, for the female die I took a small rectangle of 1/2" plate and drilled a hole the same size as the O.D . of the finished bracket near to one edge. I then hacksawed and filed this to the required U shape and took off the sharp corners.  The male die has to be one thickness smaller than the female all around but the same shape. I silver soldered the male die to a piece of 1/8" plate the same size/shape as the open edge of the female die to make it easier to hold in line in the vice before squeezing.  I hope this makes sense - if not I'll take a photo tomorrow.

Cheers,

Ray.

 

 

Hi Ray,

Thanks, yes I think I know what you mean.  I'll attempt to get the various bits this weekend, and maybe have a go! If you have chance to do a photo at all, it would be appreciated, just to clarify my thoughts - but no problem if you dont!

 

Also, I've soldered in the past, but haven't come across the term "silver soldered" is that using a different type of solder to what I would have used for soldering wires to track etc??  Sorry - get away from wood and plastics, and im something of the village idiot!

 

Richie

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As mentioned, scoring the inside edges of your folds drastically improves the ease of bending, and also helps form a "sharper" corner on the outer edge. Don't be afraid to remove a fair bit of material; there's a decent margin of forgiveness before you've removed too much and risk cracking the brass along the fold. Triangle files are perfect for making bend-friendly scores. After the fact you can come back and run some solder along the inside seam to strengthen it and file it to a nice square edge.

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Also, I've soldered in the past, but haven't come across the term "silver soldered" is that using a different type of solder to what I would have used for soldering wires to track etc??  Sorry - get away from wood and plastics, and im something of the village idiot!

 

Richie

Hi Richie,

Don't do yourself down - my pal who is a retired woodwork teacher laughs at my woodwork but I get my own back when he 'butchers' metal!

Silver soldering is a totally different method using higher melting point (silver based) solder, special flux (white powder you mix with water) and a gas torch like plumbers use. It involves much higher i.e. red heat temps.  If you don't have the gear you might get away with epoxying the 'back plate' as any forces are going to be 'in compression'. Personally I wouldn't weaken the brass by nicking it but anneal it well and put a good radius on the edge of the female die.

Cheers,

Ray.

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As mentioned, scoring the inside edges of your folds drastically improves the ease of bending, and also helps form a "sharper" corner on the outer edge. Don't be afraid to remove a fair bit of material; there's a decent margin of forgiveness before you've removed too much and risk cracking the brass along the fold. Triangle files are perfect for making bend-friendly scores. After the fact you can come back and run some solder along the inside seam to strengthen it and file it to a nice square edge.

That's fine but the OP wants a curve.

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Thanks for the replies guys.

 

Hi Richie,

Don't do yourself down - my pal who is a retired woodwork teacher laughs at my woodwork but I get my own back when he 'butchers' metal!

Silver soldering is a totally different method using higher melting point (silver based) solder, special flux (white powder you mix with water) and a gas torch like plumbers use. It involves much higher i.e. red heat temps.  If you don't have the gear you might get away with epoxying the 'back plate' as any forces are going to be 'in compression'. Personally I wouldn't weaken the brass by nicking it but anneal it well and put a good radius on the edge of the female die.

Cheers,

Ray.

 

Ray,

Thanks - oh I no my place!!! :) lol!  Thanks for that, not heard of silver solder before, but if im going to dealing with brass, it might be time to investigate and invest!

 

Cheers
Richie

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  • 3 years later...

A question > how many times can you keep annealing / bending brass? If i have a piece of work that has been bent wrong, can I anneal it, roll it flat and start again?

 

I've picked up a kit and a curve has been poorly formed and I was hoping that I could heat, flatten, heat and then re-roll to the correct profile? 

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A lot will depend on the radius of the curve,  if it's fairly generous, you should have no problem, flattening it and re- rolling it in the correct direction. Note however, that there may be some material "stretch". One further thing is to anneal it before and after flattening. If it looks like cracking, stop and anneal again. Don't try and do it all in one go.

 

 

 

 

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4 hours ago, Siberian Snooper said:

A lot will depend on the radius of the curve,  if it's fairly generous, you should have no problem, flattening it and re- rolling it in the correct direction. Note however, that there may be some material "stretch". One further thing is to anneal it before and after flattening. If it looks like cracking, stop and anneal again. Don't try and do it all in one go.

 

 

 

 


Thanks for the reply. Thanks for the tips. Will give it a go.

 

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