Small Diameter Tube & Tube Bends

[derekwarner_decoy]

Hi PD's - question for Bill [Hudson] - I saw your posting ..... "We are making tube benders" (for small tubing)....

I have the American produced DUBRO brand #785 & #786 tube benders for 1/8" & 5/32" OD diameter tube, but am still experiencing tube flattening on the inboard side of bends with the assumed wall thickness reduction on the outboard side of the bends....which is natural considering the mechanical transformation of the tube  

An example of this is seen via our PD links>>> to JMC & look at the plan view of the new triple expansion engine tubing

I have attempted annealing the brass tubing [to cherry red, then left to cool] in the planned bend location prior to bending, however this seems to have little effect/affect on the final bend tube flattening

With tubing of such small diameters it is near impossible to fill & seal the tube length with sand prior to bending....

I understand that an other   by the name of AF Campbell has previously posted & .....   :rant ...best stick to large wall thickness copper tube, but these tube runs or bends are never as straight or shiny as brass 'bits A tube'

Any PD comments greatly appreciated.................. Derek :?

[Bill Hudson]

Derek,

I was not in on the design of this bender just made some of the parts for the group effort.  This is a two wheel bender in that both wheels are the same diameter. When mated together their concave grooves are the diameter of the tubing.   They hold the tube tightly between them as the tube is being bent.   There is a "normal" diameter of bend that tubing can make with out collapsing in relation to its outside diameter. Unsupported  or too small of a bend diameter will cause the tube to flatten or collapse when  bent.
 
It is a beautiful  day and I have a golf date.   More on temp. bender later.   TTYL   Bill

[RickF]

Derek,

A trick I last used many years ago was to select a length of multicore solder of a suitable close diameter and push this down the pipe. Once bent, the application of heat and a bit off compressed air should shift any that will not pull out. Give it a try on a scrap piece first though.

Rick

PS - there used to be a product called (I think) "Cerrobend" that achieved the same purpose.

[Dave_Sohlstrom]

Bill I saw the bender that your group was selling looked very nice. Would of loved to have one but talked the wife into a 4" rotary table from Little Machine shop.

Question: Are there plan sets available for your groups bender for those that would like to build one from scratch.

Dave

[Bill Hudson]

Bill I saw the bender that your group was selling looked very nice. Would of loved to have one but talked the wife into a 4" rotary table from Little Machine shop.

Question: Are there plan sets available for your groups bender for those that would like to build one from scratch.

Dave

The benders went over very well. I finally got a set fro my contribution of labor.  Have not had any chance to see how well they work.

Little Machine shop got some money from me too.  my wife. I picked up a quick vise for my mill.

At this time I don't think the club is giving out the plans.

[scotfriend]

Hi PD's

have you ever tried to fill the tube before bending with a piece of wood that you can remove after bending. I made it as follows, the inner diameter of the tube was 2mm i bought a 1.5mm round of beech wood put it in water for half an houre and then into the tube, after bending the tube left it at a warm and dry place for a few days and then you can pull out the wood easily. This works very well for bendings of about 90 degree angle.

Kind regards Hans

[Dave_Sohlstrom]

Bill

I was not necessarily thinking of a freebee. I would be willing to pay for a set of drawings at a reasonable price. Additional cash flow for your group.

Dave   :lol:

[Dave_Sohlstrom]

Bill

I was not necessarily thinking of a freebee. I would be willing to pay for a set of drawings at a reasonable price. Additional cash flow for your group.

Dave   :lol:

[Bill Hudson]

Bill

I was not necessarily thinking of a freebee. I would be willing to pay for a set of drawings at a reasonable price. Additional cash flow for your group.

Dave   :lol:

I don't know what happened to my first reply to this.  
Dave,
The bender project was conceived several years ago but I was not in on the original development. It isn't that I/we don't want to share or sell the plans it is just that we do not own the plans. They are owned by some one outside and not associated with the club.   When we built the kits several people donated time to build various parts but we were only given a drawing for that part.  I do not have a complete set of drawings even for my self.

Bill

[Dave_Sohlstrom]

Bill

It was fairly crowded around your groups tables so I did not get a real good look at the bender that was assembled and on display. Would it be passable for you to post a few pics of the bender here on the forum.

Thanks

Dave

PS shame the group doesn't have plans available.

[Bill Hudson]

Bill

It was fairly crowded around your groups tables so I did not get a real good look at the bender that was assembled and on display. Would it be passable for you to post a few pics of the bender here on the forum.
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I'll check to see if any one took pictures. I didn't.
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Thanks

Dave

PS shame the group doesn't have plans available.

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It would be kind of counter productive to pass out (or sell) plans (even if we could)  when our goal is to sell the bender kits.  

There are a few kits left, you might just have to save up some money and buy one.   :ohno  I shipped out two last week and have three going out this week.

Bill

[Bill Hudson]

Bill

It was fairly crowded around your groups tables so I did not get a real good look at the bender that was assembled and on display. Would it be passable for you to post a few pics of the bender here on the forum.

Thanks

Dave
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Dave,  

After looking at my last message this morning it looks to me to come off a bit sarcastic but in reality it was meant to be tongue in cheek  cheek.    

I did find a photo posted on a web site I'll try to post it here although it will be a bit OT.

Bill

[Dave_Sohlstrom]

Thanks Bill

Dave