By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale Nov 29

Bending 18mm diameter brass bar

All Topics | Latest Posts

Search for:  in Thread Title in  
Joseph Noci 120/11/2018 20:34:25
458 forum posts
812 photos

I have some 18mm diameter drawn brass bar that I need to make some bends in. I am not sure of the class of brass - it 'may' be CZ121 but I am not sure. It does machine very nicely.

The bends are on a 50mm radius, although I can increase this to 70mm if need be.

I understand CZ121 can be readily hot worked at around 650deg to 700deg C. Has anyone done this with thick round or flat bar of this grade, and did it work ok?

I have tried annealing a section and the bend just cracked at less than 1/8 of the bend. so I suspect this is a material type that must be worked hot, not annealed.

Any advice would be appreciated.


Mick B120/11/2018 21:26:48
1001 forum posts
57 photos

CZ121 is basically a 60/40 Cu/Zn brass. The high zinc content - as I understand it - gives it its free machining property, but also reduces ductility as evidenced by the discontinuous chip you get on turning or drilling.

I'd be rather surprised if you can do what you want to, though hot working might open up possibilities I've never explored myself.

I'd think it would be better to try to find some bar in a higher-copper brass like CZ108, which would behave much more like cartridge brass, respond to annealing and take cold forming successfully.

I suspect this'd be an expensive exercise, however - so if brass is absolutely necessary, maybe you'd test the possibilities with what you have first.

Joseph Noci 121/11/2018 06:11:54
458 forum posts
812 photos

Thanks Mick,

I have only the info on the various material web-sites to go on and there it is indicated that hot forming is possible. I was hoping someone had already dunnit..and could say no problem!

I will give it a try and post what happens!


JasonB21/11/2018 07:11:39
15165 forum posts
1548 photos

The thickest I have bent is 5/16" square section into a 2.5" circle. I did it hot but did also have a couple of failures before I got a good one.

I would think that one of your problems will be the work loosing heat as it is put into whatever you are using to bend it with/around.

David George 121/11/2018 08:05:19
753 forum posts
261 photos

Hi Joseph, You can get a brass which is more pliable ie less likely to fracture C464 ( naval brass) or have you thought of casting the component.


Neil Wyatt21/11/2018 08:31:16
15816 forum posts
672 photos
73 articles

+1 for David's suggestion.

You will need to melt it under a flux to stop the zinc burning off.

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Support Our Partners
Allendale May 19
Eccentric July 5 2018
Eccentric Engineering
TRANSWAVE Converters
Allendale Electronics
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest