Bending stainless steel tube

[superheat6k]

I need to make a mast support bracket to hold my radar mast safely at an angle when down to allow me passage under Bursledon Bridge.

I need to make or have made a semi circular section of stainless tube 20 - 25mm diameter with an inside radius of ~200mm, and with straight tails on each side of the semi circle. I reckon a 500mm piece will turn about right with tails the correct length I require.

Any advice on how to achieve a neat turn and what wall thickness I should choose gratefully received.

Do I heat SS like I would to turn a heavy copper or steel pipe ?

Does polished SS discolour permanently after applying oxy-acetylene heat ?

 

[vas]

T.,

wouldn't it be best to order that to a SS fabricator with the right bending tools and jigs?
IIRC they have set jigs for each dia and unless I'm badly mistaken, a 30mm dia turns at approx 220mm dia, so a 20-25mm will be under 200 so maybe less than what you want.
I think they don't heat the tubing.

cheers

V.

 

[sarabande]

T

you might find it worth having a chat with PCUK. Skilled manipulator of steel tube and fittings on his own boats and for other people.

 

[ianabc]

Bent 3/4 inch real dia 316 stainless PIPE

using a hydraulic bender at a boatyard

Used the bender that comprised a hydraulic jack mounted on a horizontal ply board with 2 stops left and right to hold pipe in place.

Gently gently bent inch by inch to req bend along 40 feet for upper guardrail to be welded to ss stations

Had success even though it was my first attempt.

 

[fisherman]

Gently gently bent inch by inch to req bend along 40 feet for upper guardrail to be welded to ss stations

Had success even though it was my first attempt.

Mine was 1in steel pipe. I put one end on a chock and drove the car along it.

 

[burgundyben]

Trev - nip down to the stainless chaps at Hamble Point, Litrus Marine, take cash, he'll do it while you wait, he has a mandrel bending machine.

 

[rogerthebodger]

I need to make a mast support bracket to hold my radar mast safely at an angle when down to allow me passage under Bursledon Bridge.

I need to make or have made a semi circular section of stainless tube 20 - 25mm diameter with an inside radius of ~200mm, and with straight tails on each side of the semi circle. I reckon a 500mm piece will turn about right with tails the correct length I require.

Any advice on how to achieve a neat turn and what wall thickness I should choose gratefully received.

Do I heat SS like I would to turn a heavy copper or steel pipe ?

Does polished SS discolour permanently after applying oxy-acetylene heat ?

I am at the moment bending 22 mm dia 1.6 thick 316 polished tube with a hand bender and long lever. My bends are about 100 mm inside rad and are done cold.

http://www.adendorff.co.za/ProductD...haping/Thin-Pipe-Benders/HAND-PIPE-BENDER/331

If its thick wall tube use one of these

http://www.adendorff.co.za/ProductD...Pipe-Benders/12-TON-HYDRAULIC-PIPE-BENDER/327

 

[Brent Swain]

Bent 3/4 inch real dia 316 stainless PIPE

using a hydraulic bender at a boatyard

Used the bender that comprised a hydraulic jack mounted on a horizontal ply board with 2 stops left and right to hold pipe in place.

Gently gently bent inch by inch to req bend along 40 feet for upper guardrail to be welded to ss stations

Had success even though it was my first attempt.

Where in Comox are you?
Couldn't find you there; yet.
Sch 40 can be easily bent , with no special equipment ,and no wall collapse.

 

[sarabande]

Sch 40 can be easily bent , with no special equipment ,and no wall collapse.

Brent
I really do not believe you meant to say that .

You must spec the radius of bend, the diameter, and the wall thickness of the Schedule 40 pipe, before you make such statements, otherwise someone out in the real world will spoil a perfectly good pipe project..

 

[solent clown]

This is my day job. Brent you are talking out of the wrong orifice for this application. Yes you can bend tube slightly over a long area at various points to make a gentle curve, it is known as bump bending. You cannot just put the bend required in this case without a dedicated bender, no matter how much you try.
By the way, in a rotary bender the CLR will be about 100mm for the size of tube required in the OP.

 

[rogerthebodger]

This is my day job. Brent you are talking out of the wrong orifice for this application. Yes you can bend tube slightly over a long area at various points to make a gentle curve, it is known as bump bending. You cannot just put the bend required in this case without a dedicated bender, no matter how much you try.
By the way, in a rotary bender the CLR will be about 100mm for the size of tube required in the OP.

I used to work for a company in the UK who made tube bending equipment.

The wall thickness and bend radius and quality of bend are the key factors

Press bend with thick wall like sched 40 tube and low quality.

Mandule bending for thin wall and good quality bend.

These days if I need a tight bend in thin or thick wall tube I tend to use a wend bend cut the the required angle or a press bender for large radius bends. Roller bender for very large bends

These pics used weld bends top thin wall 38mm dis tube the lower 60mm dis sched 40 tube.

38mm O/D 1.5 mm wall roller bend with weld bends on the top of legs.

 

[solent clown]

I used to work for a company in the UK who made tube bending equipment.

The wall thickness and bend radius and quality of bend are the key factors

Press bend with thick wall like sched 40 tube and low quality.

Mandule bending for thin wall and good quality bend.

These days if I need a tight bend in thin or thick wall tube I tend to use a wend bend cut the the required angle or a press bender for large radius bends. Roller bender for very large bends

These pics used weld bends top thin wall 38mm dis tube the lower 60mm dis sched 40 tube.

38mm O/D 1.5 mm wall roller bend with weld bends on the top of legs.

yes, buying pre bends and welding might be an option for the OP. Depending on tube spec we may be able to do it FOC if we have the dies to fit. PM me Trev if that helps, but best bet is probably Litrus marine as he will know exactly what you want, and have the material in stock

 

[Brent Swain]

Brent
I really do not believe you meant to say that .

You must spec the radius of bend, the diameter, and the wall thickness of the Schedule 40 pipe, before you make such statements, otherwise someone out in the real world will spoil a perfectly good pipe project..

The term sch 40 DEFINES the measurements you give. I have bent it around pilings and trees ,into bow pulpits, with no problems.

 

[sarabande]

The term sch 40 DEFINES the measurements you give. I have bent it around pilings and trees ,into bow pulpits, with no problems.

Brent
I agree there's a relationship between size and all the other dimensions, that's part of the schedule

https://www.engineeringtoolbox.com/ansi-steel-pipes-d_305.html

But you are evading the question:

What size can you bend, to what radius, without the aid of appropriate kit or damaging the wall ?

There are at least two people on this thread saying you are not correct. You really should be prepared to give accurate details before spouting off.

 

[solent clown]

The term sch 40 DEFINES the measurements you give. I have bent it around pilings and trees ,into bow pulpits, with no problems.

schedule 40 pipe is about as far from the OPs requirements as you could go. He wants STAINLESS TUBE. TUBE, thin walled, light, and STAINLESS. I know you are the worlds expert on all, things steel., schedule 40 pipe is a thick walled mild or stainless steel, usually welded from flat rolled stock. It is very heavy, and not suitable for the application here, and there is no way on Gods green earth you will bend it to the required OPs diameter without a bender. I have bowed to your superior experience despite huge reservations as an engineer who actually studied before going out into several decades of real world experience too. BUT in this field, though you may not like it, you are not the expert. Jamming a pipe between two trees to make a hashed up pushpit in mild steel is a whole different level of bodging than bending a piece of stainless to a small radius. Get a grip

 

[Heckler]

Brent
I agree there's a relationship between size and all the other dimensions, that's part of the schedule

https://www.engineeringtoolbox.com/ansi-steel-pipes-d_305.html

But you are evading the question:

What size can you bend, to what radius, without the aid of appropriate kit or damaging the wall ?

There are at least two people on this thread saying you are not correct. You really should be prepared to give accurate details before spouting off.

Tim
I am no fan of his "shoot from the hip" style either but your original critique included the word thickness, I not surprised you got the reply you did.
http://www.mcnichols.com/?pageCode=pipedims
Stu
PS I thought schedule 40 was the same in SS as well and so did a quick check, it is.
http://www.aalco.co.uk/literature/files/aalco-stainless-steel-tube-pipe.pdf

 

[solent clown]

Brent, if that sounded rude, well hey ho. I will buy you a beer when you come this way. :encouragement: I can see where heavy pipe isnt an issue on a big steel boat, but that isnt the OPs requirement.

 

[sarabande]

Between 1/8 inch and 2 inches, there are nine separate external diameters in Sched 40, of which 3 sizes share the same nominal wall thickness. I can't imagine for a second that e.g. Solent Clown would assume that one wall thickness is related to one ext dia. That would be grossly unprofessional.

I guess that Brent is applying the great tradition of USA shade tree mechanics to marine metal work...

 

[Heckler]

Between 1/8 inch and 2 inches, there are nine separate external diameters in Sched 40, of which 3 sizes share the same nominal wall thickness. I can't imagine for a second that e.g. Solent Clown would assume that one wall thickness is related to one ext dia. That would be grossly unprofessional.

I guess that Brent is applying the great tradition of USA shade tree mechanics to marine metal work...

I used 1" pipe as a common denominator, which is what the original post was about, the thickness is the same in both materials.
Stu

 

[solent clown]

Between 1/8 inch and 2 inches, there are nine separate external diameters in Sched 40, of which 3 sizes share the same nominal wall thickness. I can't imagine for a second that e.g. Solent Clown would assume that one wall thickness is related to one ext dia. That would be grossly unprofessional.

I guess that Brent is applying the great tradition of USA shade tree mechanics to marine metal work...

Hee hee, Ironically all our bending gear is American.