How to bend brass rod?
I am building an item from HSM a few years ago and need to bend 1/8" brass rod into a 7/8" ID circle with a small gap between the two ends. I made a jig consisting of a steel plate with a 7/8" steel cylinder attached and a screw 1/8" from the cylinder. After placing the end of the brass rod between the cylinder and the screw I could bend the rod by hand around the cylinder much of the way. I do not know how to finish the bend. Grabbing the free end of the rod with pliers helped some, but completing the circle has me stumped. This seems to be a standard jig, so what am I missing?
Thanks in advance for your advice.
Continue the bend overlapping the start end by an amount as needed, then cut ends to match and twist the two ends into alignment.
The other option that is used for band rings is to calculate the length needed, shape it into a shape like two U's connected at the legs (flattened circle), solder, then shape it on a mandrel.
Like Ken said, keep bending around and then trim to length and twist so the ends meet. That's how jewelers make jump rings for chains. If you need a lot of them, just twist one long rod and cut them all off at the same time. BTW, even if the brass is dead soft, it's going to spring back a bit, usually about 10%, so your 7/8" ID will end up somewhere around .950. Depending on the purpose of the part, this might not matter, but if it needs to be close to 7/8", you'll need to start with a smaller mandrel.
Stuart de Haro
Ken is right. If you have a problem, anneal the bras rod by heating it with a propane torch to just before it turns red. Blue color is just fine. Quench in cold water. That's it.
It isn't necessary to quench the brass,though it cools faster,of course.
gwilson - Yes, you should quench it for annealing. I get good results if quenched. Have to try just heating and than compare. Thanks.
Last edited by juergenwt; 12-08-2009 at 03:14 PM.