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Bending thin-walled 4130

J.Ramsey

Hot Rolled
Joined
Feb 27, 2007
Location
Kansas
The bender he mentioned is definitely not big bucks, but it looks like he has had good results, I'd be curious to narrow down the differences.

Evidently Dave at Lowbuck doesn't build the same style bender that uses Greenlee shoes I purchased over 30 years ago.

This is what he offers today.
rVjWnHo.gif


This what mine looks like, I run it with a OTC air over hyd pump.Cycle time for a 90 degree bend on 1-3/4" .058 4130 is about 10-12 seconds.IIRC I paid $850 with one set of dies and a hand pump that was soon ditched for the OTC pump.
Obdh99M.jpg


Mittler Bros. is popular also 9deg Hydraulic Tube Bender by Mittler Bros., most dies today are machined from plate instead of cast Al. which allows bending .125 wall 4130.
 

Graham Gott

Aluminum
Joined
Jan 26, 2010
Location
Denver, NC
Columbia River Mandrel Bending is close to the OP. I've bought mild steel and aluminum bends from them at what I thought was a reasonable price. Shipping to Ohio sucks, but the OP wouldn't have that problem.

Sent from my XT1254 using Tapatalk
 

Mike C.

Diamond
Joined
Nov 25, 2004
Location
Birmingham, AL
"Clearly you have no clue! Use the proper bender, bends cold, no problem. "

I have seen all kinds of aircraft and motorcycle structures bent up out of 4130 exactly as I stated with no kinking. Wing tip bows, frame longerons, all kinds of bends. Apparently the OP doesn't have the proper bender for the work he is attempting. I know this works, if done properly.
 
Joined
Nov 19, 2007
Location
marysville ohio
Columbia River Mandrel Bending is close to the OP. I've bought mild steel and aluminum bends from them at what I thought was a reasonable price. Shipping to Ohio sucks, but the OP wouldn't have that problem.

Sent from my XT1254 using Tapatalk

So just go to Tube Techniques in Columbus Ohio. They can do about anything and they are in central Ohio.
 

lionelt

Stainless
Joined
Nov 25, 2010
Location
Oxfordshire
I tried getting it hot, it just seemed to exaggerate the failure, it kinked right away and flattened easier, and eventually split.
The bend itself doesn't require much effort with the setup I have, its just the issue with kinks forming.

What size tubing are those frames? I'm wondering why you had success with your setup and I am struggling so much. My bender is pretty rigid and the dies look like they were machined well enough.
Ideally down the road I will be using even thinner tubing so if I can find a reliable way to do it myself that puts me way ahead of the game.


Another way for tight bends is filling the tube with hot bitumen and bending when the tar is set cold.

This was used on motorcycle exhausts, was told this by an old guy many years ago, and it just came back to me.
 

HuFlungDung

Diamond
Joined
Jan 19, 2005
Location
Canada
I've never tried this idea: get a bundle of wire and stuff the tube full. Leave a few pieces extra long so that you can somehow winch them out. Once you pull a few pieces after the bend, it should loosen the bundle and you can just pull them out. I'm thinking steel wire, maybe some solid .045" MIG wire that is fairly springy and tends to stay straight. You might bundle the bulk of the wire in a permanent bundle so it stays assembled as a bundle instead of falling all over the place and getting twisted up. You'd just need to pull a few pieces to loosen and those pieces might have to be replaced.
 

EvansER89

Aluminum
Joined
Dec 23, 2014
Thanks everyone for the suggestions. I sent out a few RFQs, its been hard to find a place that will do low quantities but I have my fingers crossed.
I think I'll try packing it with welding rods as was suggested, and probably give the Woods metal technique a shot as well. Worst case scenario I may have to go back to the drawing board if I can't get acceptable results with my current equipment.
 

dian

Titanium
Joined
Feb 22, 2010
Location
ch
Another way for tight bends is filling the tube with hot bitumen and bending when the tar is set cold.

This was used on motorcycle exhausts, was told this by an old guy many years ago, and it just came back to me.

really? how hard can cold bitumen get?
 

EvansER89

Aluminum
Joined
Dec 23, 2014
What is your current bender ?.

I believe it is this bender: JMR TBM-25R RaceLine Manual Tubing Bender, Tube Pipe and Square but I am not sure, my partner on this project actually purchased the unit. I know its not the right kind of unit for bending thin walled materials but its perfect for a lot of other projects which is why I've been trying to make it work. An extension has been added using 2" square tube and some all thread so that I can position the mandrels I cut inside the bend.
Mandrel setup is similar to to this, just a slightly larger scale: Aluminium Tube bending - pushing the limits - YouTube
 

rcoope

Stainless
Joined
Sep 25, 2010
Location
Vancouver Canada
We have a lot of cerrobend around as its used for electron beam shaping for cancer radiotherapy. So we can use it for stuff like bending very thin wall tubes, like .25" OD x .015" wall stainless. This was its original purpose, bending aircraft hydraulic tubing but I suspect they've found other ways to do it for that application. The interesting thing about cerrobend is it really only works for tubing as I've described if you cool it down quickly after you pour it in so it makes small crystals as it solidifies. If you don't, the tubing just breaks and you can readily see the difference in the structure of the solidified cerrobend. And of course this requires a great deal of mucking about with hot and cold water baths or propane torches and plugs to get the stuff in, remelted, and then rapidly cooled without it leaking out. Which might explain why it might not work well for thicker tubes. On that note, my guys and friends of mine have tried other methods like packed sand or water and none of it seemed to work, perhaps because you couldn't get it solid enough. I suspect the whole filling tubes thing is another great archaic tool process like power hacksaws and lathe dogs. For tubes like the OP is talking about, like most here I'd go to a pro shop like say, Aggressive Bending here in the Lower Mainland, and have them do it on their mandrel machines.

As an amusing footnote, cerrobend is really like the molten metal guy in Terminator, and it's dense enough that a wrench for example, will float in it. As we have a pot of the stuff permanently melted in room near our shop, I often show visitors as a floating wrench is not something you see every day.
 

HuFlungDung

Diamond
Joined
Jan 19, 2005
Location
Canada
We have a lot of cerrobend around as its used for electron beam shaping for cancer radiotherapy. So we can use it for stuff like bending very thin wall tubes, like .25" OD x .015" wall stainless. This was its original purpose, bending aircraft hydraulic tubing but I suspect they've found other ways to do it for that application. The interesting thing about cerrobend is it really only works for tubing as I've described if you cool it down quickly after you pour it in so it makes small crystals as it solidifies. If you don't, the tubing just breaks and you can readily see the difference in the structure of the solidified cerrobend. And of course this requires a great deal of mucking about with hot and cold water baths or propane torches and plugs to get the stuff in, remelted, and then rapidly cooled without it leaking out. Which might explain why it might not work well for thicker tubes. On that note, my guys and friends of mine have tried other methods like packed sand or water and none of it seemed to work, perhaps because you couldn't get it solid enough. I suspect the whole filling tubes thing is another great archaic tool process like power hacksaws and lathe dogs. For tubes like the OP is talking about, like most here I'd go to a pro shop like say, Aggressive Bending here in the Lower Mainland, and have them do it on their mandrel machines.

As an amusing footnote, cerrobend is really like the molten metal guy in Terminator, and it's dense enough that a wrench for example, will float in it. As we have a pot of the stuff permanently melted in room near our shop, I often show visitors as a floating wrench is not something you see every day.

So what would happen if you chilled the Cerrobend by tossing in a large volume of steel balls? This would have the beneficial effect of requiring less alloy, too. Just heat the mess up as usual to extract the balls.
 

rcoope

Stainless
Joined
Sep 25, 2010
Location
Vancouver Canada
In a small tube our experience was you needed to plug one end, get the cerrobend into the tube, but it would flash freeze along the way so you needed to do some heating and cooling cycles with a torch or hot water to make sure you had no air gaps in the cerrobend adjacent the area you're going to bend. Then heat again to make sure it's liquid and then chill fast by dropping the tube in cold water with both ends plugged. You'd never get steel balls in there. The main project we used this for with the .015" wall tube involved short pieces of .25" tube, maybe 7" long. I can't imagine what they did for aircraft lines. I would have built heated vertical reservoirs as long as the tube run and then some affair with torches above a cold water reservoir for the flash freezing. The good news is you could take a long straight piece of tube, fill it with nice small crystal flash frozen cerrobend once, then bend it how you wanted to at leisure, so not so bad. I'd love to know how they actually did it. Any old tube bending hands around here?

Edit. here is a link which may have been where we found the original directions for the project I described, back in 2010: http://www.hitechalloys.com/hitechalloys_005.htm Note this page seems defunct so indeed the whole field seems shrouded in mystery and folk wisdom.
 








 
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