tube bender

[forstonc]

I am wanting to make a tube bender. I have a small 9x19 lathe that I can use to turn the tube rollers, but my question, how to cut the tube diameter from the raw stock? I've seen the radius turning tools that you can buy/make, but these are for turning ball radius or external radius, I don't think they work for an internal radius like what the tube rollers would need. Anyone have any experience making these? I could really use the advise.

Thanks,
Cody

[aametalmaster]

I have a ball turner/radius maker that i built for my SB 10" lathe. I can do up to 3" dia b a l l s and a nice 3" groove in plate but my lathe is way too small to do the larger OD dies. What size tube are you planning to bend?...Bob
Plans here>>> http://groups.yahoo.com/group/southbend10k/

[jamscal]

I tried to find a link for a tool that could this but couldn't.

Basically a guy tool a piece of drill rod the same diameter of the tube he wanted to bend, faced it in his lathe and then cut a lip into it, relieved the edge, and then parted it off. It was maybe 1/2 thick.

Then he mounted this in his lathe tool holder, flat, and voila, a form tool the exact radius he needed for his project.

You'd probably have to take out the majority of the material with conventional lathe tools, but this would get you there.

He heat treated it too, IIRC.

Good luck,

James

[forstonc]

I would mostly be doing 1 1/2" and smaller, but may occasionally do up to 2".
So you are saying that your radius tool could do that? I was worried about not being able to get it deep enough into the work before the back side would hit. If that would work, I would get one. I might try the drill rod approach as well, but not sure how easy it will be to find it that big. Sounds like a good approach. Thank you for the replies.

[jamscal]

$22 for 1 foot of 1 1/2" dia drill rod from McMaster-Carr. They have up to 2"

-James

Edit: Found the site:

http://www.frets.com/FRETSPages/Machining/Projects/BigBender/bigbender.html

Great site

[forstonc]

Thanks James,
I checked that link out, and that seems to be the cheapest and quickest way for me to try first. Also, thanks for the lead on where to get the drill rod. I'll have to post some pics once I finish it.
Cody
Thank you both for your suggestions!!

[fun4now]

metal lathes are soooo cool.

[aametalmaster]

[QUOTE=forstonc;26099]I would mostly be doing 1 1/2" and smaller, but may occasionally do up to 2".
QUOTE]

I don't think your 9" lathe can swing a big enough blank to make a 2" tube die as well as have enough power to hog a piece of drill rod into a groove. Maybe with a bigger lathe but not a 9". Plus isn't the rule of thumb 6 time's the tube dia for the die diameter so a 2" die will be cut from a 12" blank. Just my thoughts. I make vee groove pulleys all the time and just hogging the bit straight in takes some power. I found little cuts are faster thats why radius tools work so well. Keep us posted...Bob

[jamscal]

He may have trouble with the large dies, but making a tool per the website out of drill rod will be no trouble at all.

I think a 1 1/2 tube will need a 4 1/2 bend radius at least....that's the 9" right there, so, yea, that might be a problem.

I was thinking about trying to make dies out out of 1/4 plate. I was thinking I could plasma cut circles out and sandwich them together. The inner circles would be smaller than the outside, to roughly approximate the inside radius. Then, my plan goes, I could weld them together, chuck them up into the lathe, and finish them out.

Just a thought.

-James

[forstonc]

Oh. I did not know about the rule of thumb, 6 times tube diameter. Well, I guess that shoots that idea, until I can come up with another idea. What about setting one up like a ring roller, you know, with 3 dies in sort of a pyramid? And if that kinks it, maybe even using 6 die, 2 at each point of the pyramid to sandwich it? Just some thoughts going out here. This way my bend radius could be 3 times or even more, but the dies would'nt have to be as big, only 3 or 4 inches. Any thoughts on this?

[BWS29128]

He may have trouble with the large dies, but making a tool per the website out of drill rod will be no trouble at all.

I think a 1 1/2 tube will need a 4 1/2 bend radius at least....that's the 9" right there, so, yea, that might be a problem.

I was thinking about trying to make dies out out of 1/4 plate. I was thinking I could plasma cut circles out and sandwich them together. The inner circles would be smaller than the outside, to roughly approximate the inside radius. Then, my plan goes, I could weld them together, chuck them up into the lathe, and finish them out.

Just a thought.

-James

I've had some fantasies along this route, but I keep coming back to the point that I could/can only weld "so" far with my different pieces and then I'm still going to have an awfully lot of "blank steel" with no weld holding it. And also, once I turn it down to the point that it's smooth, I will have ground through most of my weld bead...if not all of it.

[fun4now]

maybe you could plug weld the Pisces together so it would not effect the lathing surfaces. although it may throw it out of balance a bit, but it should be ok long enough to cut it if you clean up the welds. you would have to do that any way to add the next plate. just offset the weld plugs from one plate to the next so you don't have a weld all the way threw it in one place.
if it works send me a set.

[Old Sporty]

Why not build your bender around the Pro Tools dies? Might be more cost effective.

I know, it's nice to use a tool if you have it, but sometimes it makes more sense to build the bender and buy the dies.

Just a thought.

BTW, I have 12" lathe and wouldn't think twice about buying the dies. To turn a full set is a tremendous amount of work especially on a manual lathe.

Lots of luck whichever way you go.

[jamscal]

Good idea on the plug welds fun4now.

I think proper plug welds will be fine. The worst case scenerio is splitting a die.

Or, if the die has enough 'meat' you could possible bolt through in several spots.

I plan on buying a bender ( cheap for what you get) and making some of the smaller/specialty dies, some of which cost almost as much as a bender.

I plan on buying a 1 1/2 die set, which is a couple hundred dollars, adding more as necessary, and attempting to make some of the smaller dies myself.

-James

[monte55]

I haven't looked at them closely but what about the gate roller wheels that roll on round stock. Might be worth a look.