Bending brass tubing

[gilessim]

Dennis, thats exactly the method I was trying to describe, only your photo says it all! unfortunately my camera is still being fixed, anyway that worked very well for me too!

Giles

 

[stevehuckss396]

I tried something like that with no luck. It did work on some 1/16 I bent for the overflow tube on the radiator.

 

[4156df]

Giles,
You described the method very well. I should have referenced your post with my photo, and would have, but I completely missed it. Sorry.
Regards,
Dennis

 

[stevehuckss396]

Tried again today, failed!

The tubing was annealed and filled with salt. The tubing bent way better than the metal filled tubing. I think the problem may be that i am just trying to bend to tight. With a bit of math, i found that the inside bending radius is smaller than the diameter of the tubing.

I am going to try to build another bender with larger rollers and get the bend radius bigger than the tube diameter.

I almost had it!!

 

[steamer]

Steve,

Yes I would stay above 1 tube diameter for the ID Radius....definitely.

 

[stevehuckss396]

From what i have been reading, industry standard is 2-1/2 times the diameter of the tube, to the centerline radius. With the right bender type you can go alot less than that.

My dies were .75 in diameter. That would be .375 to the centerline. that is only 1.3 times.

The plan is to go to a 1.125 roller and that would put me at about 2X to the centerline.

I did make a bend on a 5/16 bender. The bend was very smooth but the tubing did "egg" being the shoe was to wide. That is why i think the increase in radius would help out.

 

[steamer]

The standard for Boiler tubes is a radius of 4X diameter....MIN.

Other wise you get too much wall thickness reduction....


Dave

PS just sent you an email...amazing what you can find.

Dave

 

[user 284]

I'm not 100% sure this will work but try making a partial bend then anneal, bend some more,anneal, repeate as required. Brass and copper work harden far faster than you would expect so what may??? be happening with such thin walled tube is it is work hardening part way thru the bend

Pete

 

[onetimeguy]

This is a bit late but I just stumbled across this thread. It may not help your situation since it seems like you have tried other things, but bismuth causes embrittles copper horribly. That's why the tubing cracks off when you fill it with the bismuth. The same thing happens with any copper alloy (brass, bronze, etc).

Here's a tidbit from an abstract of a paper, although there's lots of information on this.
http://adsabs.harvard.edu/abs/2004APS..MARP32001C


Hope this helps someone in the future!

 

[Engine maker]

I finished up a Morton M-5 last year and had to bend 3/16 bass tube with 3/16 radi for the intake pipes with good success. First I annealed the tubes. I was lucky because I had a fire in the fire place the night before and had a whole bucket of ashes. There were still even some burning embers left. I just put the tubing in the bucket of ashes and completely covered the tubing. I let it sit till it was completely cool. About 2 days in my case. When the tubing came out it was no stronger then 16Ga. copper wire. I then filled the tubes with a product called cerrobend (you can also use cerrosafe one melts at about 125 degrees and the other at about 145 degrees.) You can get small bars on e-bay. After that just take your time and bend away. I would suggest you bend around something just to get things uniform. When done you can either drop the part in hot water or just hold a torch on it for a few seconds and out it comes ready to be used again. Here's a a pic of some of the bends.

Jim

 

[kustomkb]

Wow Jim! nice engine, paint looks pretty sharp too!

Why not post a few more pics in the gallery section.

-Kevin.

 

[cobra428]

Very Nice Engine Maker. I already told you about my dads M-5.
Tony

 

[ChooChooMike]

I finished up a Morton m-5 last year

Jim - how dare you taunt us like that with just a few pictures of that beautiful engine !!

We NEED some pictures of it - especially a video of it running :bow: :bow:



Mike

 

[Engine maker]

I"ll probably never run it again. Built it to original 1940's drawings and a lot of the original parts are too weak. Broke push rods on the first run. Not real proud of it for that reason, if it can't be run what good is it. May built another someday with updated parts.

Jim

 

[zeeprogrammer]

if it doesn't run what good is it.

To admire.
To inspire.
To learn from.
To...I don't know...experience in many ways.

It's a beautiful engine. Whether it runs or not...there's a lot of good about.
I'm glad I saw it. I was impressed...if that means anything.

 

[steamer]

Jim,

Beef them up! ;D.......Persistence my friend....it will be fine.

 

[vlmarshall]

No kidding! Fix what breaks and run that beastie! :bow:

 

[Engine maker]

Well talking to people in the know, you beef up the push rods to 3/32, then the rocker arms fail. Beef up the rocker arms and the connecting pin between the front and rear crankshaft fail. See where this is headed. Easier to start over and build in all the updates.
Some day?

 

[vlmarshall]

Ah, that's awful.
However, real-world engine building is the same way...at least when you start adding performance goodies.

What's wrong with the rocker arm geometry? Springs too stiff? Ratio too high? Cam profile too severe? Something must be wrong or the rockers wouldn't be in an "Us-or-Them" battle with the pushrods.

Fixing it sounds like it'd be fun, and that's where I'd head before replacing the engine.


Edit: Besides, I want to see it running! ;D

 

[Gatman44]

For bending thin wall brass tubing try anealing it and filling it with Bismuth. Works for me.