I was hoping to use a 5' pipe on one end and a vise on the other with
a 3 1/2" pipe (it has to end to be a 3 1/2" inner diameter U-bolt).
It'll be 316 grade steel for marine environment use.

Can I cold bend it? Is a 5' pipe enough leverage?

Should I heat it with a welder's propane torch as I bend it?

On Aug 28, 1:41 pm, wrote:
I was hoping to use a 5' pipe on one end and a vise on the other with
a 3 1/2" pipe (it has to end to be a 3 1/2" inner diameter U-bolt).
It'll be 316 grade steel for marine environment use.

Can I cold bend it? Is a 5' pipe enough leverage?

Should I heat it with a welder's propane torch as I bend it?

Material condition? (hardness? yield strength?)


Getting a 3/4" 316SS rod (threaded?) to conform (by hand) to the OD
(3 1/2") of a 3" pipe is going to be a little hard.

Have you considered an "off the shelf" SS U bolt?



http://www.allmetalcorp.com/htm/pg009_06.htm

has them in 3/8" & 1/2"

cheers
Bob

wrote:
I was hoping to use a 5' pipe on one end and a vise on the other with
a 3 1/2" pipe (it has to end to be a 3 1/2" inner diameter U-bolt).
It'll be 316 grade steel for marine environment use.

Can I cold bend it? Is a 5' pipe enough leverage?

Should I heat it with a welder's propane torch as I bend it?

This is a little better than a guess - I used to bend 1/2" 0.090" wall
316 tubing by hand. The bender I used had about 24" handles. It was hard
work to do all afternoon. Surprisingly, 1/2" tubing was quite a bit
harder to bend than 2/8" tubing. I am going to guess that barstock will
be harder to bend than tubing and 3/4" a lot harder to bend than 1/2".

Bending a tight, smooth radius corner in this bar is not going to be
easy either.

I think I would try to find someone with a hydraulic tubing bender for
this job, but I won't say it is not possible to do by hand.

Good luck and let us know how it turns out!
Bob

BobH wrote:
wrote:

I was hoping to use a 5' pipe on one end and a vise on the other with
a 3 1/2" pipe (it has to end to be a 3 1/2" inner diameter U-bolt).
It'll be 316 grade steel for marine environment use.

Can I cold bend it? Is a 5' pipe enough leverage?

Should I heat it with a welder's propane torch as I bend it?


I did something just about like this one time when my father-in-law
wanted a stainless dinner bell. My buddy set up his Hossfeld bender
and we made the 2 bends fine, then had to tweak it slightly to get
it planar. The bends were perfect, identical radius.

I think you should buy a 3 1/2" stainless U-bolt from a trailer supply.

See for example: http://www.championtrailers.com/SS_BOLTS_UBOLTS.HTM

Grant

BobH wrote:
wrote:
I was hoping to use a 5' pipe on one end and a vise on the other with
a 3 1/2" pipe (it has to end to be a 3 1/2" inner diameter U-bolt).
It'll be 316 grade steel for marine environment use.

Can I cold bend it? Is a 5' pipe enough leverage?

Should I heat it with a welder's propane torch as I bend it?

This is a little better than a guess - I used to bend 1/2" 0.090" wall
316 tubing by hand. The bender I used had about 24" handles. It was hard
work to do all afternoon. Surprisingly, 1/2" tubing was quite a bit
harder to bend than 2/8" tubing. I am going to guess that barstock will
be harder to bend than tubing and 3/4" a lot harder to bend than 1/2".

Bending a tight, smooth radius corner in this bar is not going to be
easy either.

I think I would try to find someone with a hydraulic tubing bender for
this job, but I won't say it is not possible to do by hand.

Good luck and let us know how it turns out!
Bob

A good truck service shop should be able to do it, or they'll know
someone who bends u-bolts.. pretty common thing around my neck of the woods.

John

Thanks for the excellent feedback. It came down to having a local
metal shop who will custom bend 3/4", 36" long fully threaded rods.
The work involved to make sure the bends are exact is too much work.
I have to have 20 units done, with no errors. The cost: $25/ft x 3ft
ea= $75 x 20 units.

Most trailer shops/mechanic places don't have 3/4" thick 316 stainless
steel u-bolts. I mean completely like the letter "U", no 90 degree
bends. The closest I got was pipe braces, but all of them aren't thick
& long enough.

On Wed, 29 Aug 2007 16:27:14 -0700, wrote:

Thanks for the excellent feedback. It came down to having a local
metal shop who will custom bend 3/4", 36" long fully threaded rods.

If they're bending them hot, make sure to use 316L (extra low carbon),
or treat them to eliminate the possibility of carbide precipitation.

--
Ned Simmons