How can I put a 120° bend in 3/4" diameter rod?

[ebinmaine 75,914]

 

I need to bend a couple pieces of 3/4-in rod to use for the spindles on Colossus

I don't have any kind of a bender.

I do have a pretty rugged vise.

I have some black iron pipe I could use for leverage and a torch to heat the joint.

 

Only thing is I need to get the bend as small as possible while leaving the two legs COMPLETELY STRAIGHT.

 

How can I go about doing this?

 

 

[AMC RULES 37,251]

 

[peter lena 9,576]

EBIN,  number one thing you need is heavy solid strength and a manual , leverage geared tube bender , while you can use heat to help , you will probably need a third arm to do it. a solid leverage curved jaw against another solid point will do it . pete

[WHNJ701 4,168]

On the one panzer I made all the lift bars.  I made the bends by "cold" bending.  It's all about a good vise that's bolted down good and a 4 foot piece of bethlehem steel pipe.

[JoeM 9,328]

Good Video. I would use the vise and put both pieces together in the vise at the start of where you want the bend. Make a small wire bent to same angle so you can put it against the rod as a gauge. You say you have a torch and need to heat both pieces putting more heat to the outside of the bend area because this area must stretch more than the inside. I would say you need to heat an area twice the thickness of the material to get that tight bend . About 1 1/2" because you want a tight bend. You can always leave extra material on both side and trim to fit. Hope this helps. 

[formariz 12,353]

48 minutes ago, ebinmaine said:

Only thing is I need to get the bend as small as possible while leaving the two legs COMPLETELY STRAIGHT.

I bent a few dozen pieces of 5/8" some time back for HL5 light brackets that had to have the same requirement of a sharp bend and straight arms. I heated area to cherry red, placed on stout vise  and heated again while on vise. Then at the same time as while applying very gentle slow pressure to bend with a piece of black pipe, I hit back of bend with a heavy square hammer, pretty much the way it is done in blacksmithing on an anvil. Bends were sharp and legs were straight. I had a template for bend that I would check with. Any deviation from desired angle was easily corrected by a little heat and pressure. You will need a little practice  with the length of black pipe and hitting at the same time with the other hand but it is easy. Secret also is to properly heat area and keeping it hot until bend is achieved, hence the reason to heat it again while on vise. I kept the torch also going on the side in case things got a little tough so I could just reheat it again immediately.

[DennisThornton 4,772]

Heat, leverage or both.

[wallfish 18,792]

to Caz's post

But when you state "torch" do you mean a propane or map gas bottle torch? An Oxy Acetylene torch will allow you heat a more concentrated area hot enough and make a tight bend

Edited January 24, 2021 by wallfish

[formariz 12,353]

I use the MAP bottle and just keep it going standing next to me while I hammer on it. This way I can quickly reapply heat as needed. It’s like part of my little black smithing center. I use it also to soften plane irons to be shaped and then retempering.

Edited January 24, 2021 by formariz

[wallfish 18,792]

Adding a little bit of oxygen to the fire makes a huge difference in the amount the heat. And how it can be more concentrated to a smaller area and controlled. You don't need to go big expensive oxy acetylene tanks to do it. 

https://www.homedepot.com/p/Bernzomatic-WK5500-Brazing-Torch-Kit-361487/300055608

[DennisThornton 4,772]

For sure Oxy/Acet is faster but not a must.  MAP helps but so does that specific torch:

Bernzomatic Premium Torch Head TS8000T

But even a charcoal fire would work.

[ebinmaine 75,914]

Love this site. .

 

Asks question and within just a few minutes several answers. 

 

The "torch" is just a handheld with an old black tank. I don't remember what's in it. 

 

I did try to bend a piece experimentally. 

The torch I have just doesn't get anything to do with red hot. 

I was able to bend it with a 3 foot piece of iron pipe and a large me for leverage. 

 

I found that the last 2" just before the bend was not quite straight. 

Perhaps a slightly smaller diameter and longer piece of pipe would work better. 

 

Ideally of course... More heat.  

 

 

[MikMacMike 494]

Yupper oxi acet is the way to go but yes they are more dollars to purchase, there are some good used sets though out there, I did see this one vid where they used electric coil around the rod, it blew my mind how it heated cherry red faster then even my oxy acet torch. Not sure how he built it but it was a DIY setup!!!

[ecsi635j 34]

Hello

 Not sure if this helps, but many years ago I had to fab up two front spindles for my old Bolens .So I went down  and purchased some 3/4"  cold rolled bar stock, I then took a bit larger  diameter chrome plated bar stock, welded the two Parallel a few inches apart onto some flat plate  I then set the 3/4' bar stock across the two welded parallel bars ,decided where I wanted the bend, set the assembly on my harbor freight hydraulic press, then took a another piece of round stock placed it across my work piece and applied pressure at my bend point . no heat involved, I didn't want to anneal the metal.

I used an angle finder to get the exact angle.

Edited January 24, 2021 by ecsi635j
wrong spelling

[formariz 12,353]

The other thing to keep in mind is not to cut piece to exact length. Leave it long. Bends do not always fall exactly where needed. Cut to length after bending.

[ecsi635j 34]

Exactly! what @formariz said.

[DennisThornton 4,772]

 

I don't have one yet but I've been looking.  Not for everything but this is pretty awesome.  And there are lots of others.

https://www.amazon.com/Solary-Magnetic-Induction-Automotive-Flameless/dp/B0851C6Q22/ref=asc_df_B0851C6Q22/?tag=hyprod-20&linkCode=df0&hvadid=416709561491&hvpos=&hvnetw=g&hvrand=11392564406363392363&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9005048&hvtargid=pla-898069353504&psc=1&tag=&ref=&adgrpid=97957279110&hvpone=&hvptwo=&hvadid=416709561491&hvpos=&hvnetw=g&hvrand=11392564406363392363&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9005048&hvtargid=pla-898069353504

[AMC RULES 37,251]

Betting Trina could do it for you Eric.

 

Edited January 24, 2021 by AMC RULES

[Ed Kennell 43,851]

This is the arrangement I use to make short bends. The ends remain straight as no force is applied to the straight sections.      The inside radius of the bend will be determined by the length between the two bending points.  The outside will stretch and the inside will not compress.     I have copper jaws for the vise and pipe wrench.   With the bend area heated cherry red, 2"rounds can be bent with the 24" pipe wrench.

You must over bend as the stretched outside radius  will shrink as it cools resulting in less bend.   Small bend adjustments can be made by applying heat to the correct side of the bend.

Oxy/Ac   torch works great for fine control of heating the desired area.  The Mapp torches may work, but I have no experience with these torches.

 

 

[WHNJ701 4,168]

1 hour ago, ebinmaine said:

Love this site. .

 

Asks question and within just a few minutes several answers. 

 

The "torch" is just a handheld with an old black tank. I don't remember what's in it. 

 

I did try to bend a piece experimentally. 

The torch I have just doesn't get anything to do with red hot. 

I was able to bend it with a 3 foot piece of iron pipe and a large me for leverage. 

 

I found that the last 2" just before the bend was not quite straight. 

Perhaps a slightly smaller diameter and longer piece of pipe would work better. 

 

Ideally of course... More heat.  

 

 

Or just use your superman powers and stare at it til bends on it's own

[Tractorhead 9,215]

I have only a adjustable Propane torch, that has a adjustable Air Gas Ratio nozzle.

With that you be able to support a sharp bending a bit ( dark red Glow on 20 mm is possible) ,

but it depends it‘s time to heat up the Steel to that Heat.

 

No comparable to an Oxy Torch but it‘s Flame tip can reach nearly 1200deg C.

That‘s enough, but you have few Gasbottles aside while heat up. It burns a lot of Gas.

 

As a alternative, there are also cheapo Oxy torches Available, they work with propane and oxygene.

but this bottles are here very expensive.

Edited January 24, 2021 by Tractorhead

[wallfish 18,792]

5 hours ago, ebinmaine said:

3/4-in rod to use for the spindles on Colossus

Thought you were going with 1 inch spindles and trailer hubs. Guess I'll need to go read through the Colossus thread.

Why can't you just use WH spindles?

[DennisThornton 4,772]

8 minutes ago, wallfish said:

Thought you were going with 1 inch spindles and trailer hubs. Guess I'll need to go read through the Colossus thread.

Why can't you just use WH spindles?

I expected the same.

Edited January 24, 2021 by DennisThornton
goofed

[DennisThornton 4,772]

I thought the TS8000 was the most powerful propane torch around but maybe that has changed.  Hard to believe it will braze 1/2"!

[ebinmaine 75,914]

27 minutes ago, wallfish said:

Thought you were going with 1 inch spindles and trailer hubs. Guess I'll need to go read through the Colossus thread.

Why can't you just use WH spindles?

 

21 minutes ago, DennisThornton said:

I expected the same.

 

I am using 1" spindles yes. 

What I need is the vertical portion which is 3/4". 

I can't use Horse spindles because it has a custom built axle which is about 1.5" taller than a Horse axle. 

I was planning to use the spindles that were in it but they badly cobb welded. 

 

I figured I can cut those apart since they're junk anyway and use the turning arm on the replacements.