Bending Brass into a Ring

[raynerd]

Hello

I`m struggling trying to bend a 180mm length, 20mm wide by 1.5mm thick half hard brass into a circle. I`ve calculated that the diameter of the circle formed will be 57.3mm so I`ve made a metal former and I`ve tried to bend the metal around that. The problems I`m having are:

1. The very ends are not bending properly, they are still straight when you look closely and so consequently the ends are not butting together properly.

2. There is lots of spring in the brass and so I`m struggling to even hold the two ends together.

3. Although I`ve made a former, the brass is so stiff that I can`t get it to perfectly fold around the former, I`m not strong enough.

Any suggestions would be helpful. The idea is to silver solder the joint together!!

Chris

[sbwhart]

Have you annealed it ?.

If not heat it up the cherry red and quench in water or allow to cool on its own, you may have to form the hoop in stages annealing between each stage, this is because brass work hardens.

Stew

[NickG]

Could try to clamp one end of the brass onto the former right at the end of the brass, in a vice or something to bend that first, then do the other end then the middle bit. As Stew says though, you might need to anneal it quite a few times.

[picclock]

You could try rolling the brass between two cylinders of different diameter - but would still probably need to be annealed. The tighter the force holding the cylinders together the more it will bend. Just keep rolling until the required diameter reached. This will round the ends that you are having trouble with, although it will mean lashing something up to do it.

Best Regards

picclock

PS love the clock thread

[timeone]

anneal it first bend it round the former than clamp it ans solder you could even put it in the lathe and take a cut or 2 to get it right

[Jasonb]

Put a big jubilee clip around it.

Its very hard to bend or even roll a strip right to the ends, you may have to do a little work with a block of wood and a hammer over a slightly smaller dia former once its soldered up.

[mklotz]

After annealing, wrap it 450 degrees (turn and a quarter) around your former, then saw through at the 360 degree point, flatten, and then solder the two ends.

[Jasonb]

I think hes already cut the metal but it is a good suggestion.

Chris if you have already cut the metal you may not get the size you want as the method of calculating the length is not measured on the outside or inside dia it is approx 1/3 of the way through the metal. So given your metal thickness the actual dia will likely be 59.3mm OD.

J

[75Plus]

Chris,

Have you considered using a bit of brass pipe? I have used it to make weights for weight driven clocks many times. I have a piece 58.42mm dia. with 3.33mm wall thickness that I would be happy to share with you. Check your PM box.

Joe

[raynerd]

 

Very very sorry! I of course read all your replies and used the advice given here to solve my problem. I posted a link to my ring sundial and presumed I had replied here to say thanks for the help but I hadn`t!

http://madmodder.net/index.php?topic=5641.0


Just to clarify incase anyone else has a similar problem, I heated to cherry red and quenched as suggested initially by Stew and many others. This immediately solved 99% of my problems. The ring bent much more easily and had virtually no spring to it! It was incredible really what must be happening at a molecular level!! It went from virtually not being able to push the two ends together to being able to do it in one hand with thumb and forefinger!!

Marv - Jason was correct, I had already cut to size but next time, your method is much more sensible. I did however use your advice and slightly overbend it around a smaller former (only by a small amount) and by the time I let go, it pretty much sprung back by a fraction to perfectly mate the two ends. 


So many thanks to all of you for your suggestions and sorry for the lateness of the reply!

Chris

[mklotz]

Marv - Jason was correct, I had already cut to size but next time, your method is much more sensible. I did however use your advice and slightly overbend it around a smaller former (only by a small amount) and by the time I let go, it pretty much sprung back by a fraction to perfectly mate the two ends. 

FWIW, my suggestion was based on the way jewelers make "jump rings", the tiny split rings used to connect various bits and pieces of earrings, etc..  They wind the (annealed) wire onto a mandrel as if making a spring, then make a single cut along the length of the mandrel with a jeweler's saw.  Once removed, the individual rings are easily bent closed.

[raynerd]

Marv, that actually is even more interesting because the next job is to make a little brass ring to connect that chain that is on the way (and has been for the last week!!) from ebay.

I`ll try that method for sure.

Thanks
Chris

[Jasonb]

Yes I've used Marv's method several times both for round and oval rings, like these steering links, probably a bit thicker than on your clock at 1/8".

Just one other thing if you have a lot of brass bending to do then get the softer CZ106 or 108 as it bends far easier than the hard brass CZ120 that you are probably using for the clock.

J

[raynerd]

Hi Jason, yes the bending was purely for the sundial in the link above. The brass was half hard which I believe was CZ108. The instructions were to use CZ106 as it is easier to bend but I was strongly advised that it was too soft to engrave. Of course CZ120 would have been best for engraving but hardest to bend which is why I went half way.

Thanks again
Chris