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tom finck
07-14-2009, 05:58 PM
Hello Folks:

Newbee here, I need to straighten some 3/8 OD soft copper tube, anybody know where I can get plans for this or in an effort to save time buy one

Thanks all
Tom

Boucher
07-14-2009, 06:39 PM
I would start by rolling it out into the vee of a piece of angle iron. I have never seen a straightner. Wire is straightned by drawing it thru a reducing die. If it is bent or egg shaped more than the normal coiling a clamp type die could be worked along the length. This is just the thoughts of a sidewalk superintendant. Good Luck!!

tom finck
07-14-2009, 06:53 PM
Thanks But I think there is a way to do it with a series of rollers, anybody have one floating around?

tattoomike68
07-14-2009, 06:54 PM
I would use 2 peices of 2" By 1" angle iron. and 5 rolls. 4 drive rolls chain driven in sync and one straitening roll thats agustable by a screw. much like the way a wire feed welder works, use a power drill to power it.

if you are crafty you could add an air cylender, band saw and stop switch so it would be set for a length and it would straiten and cut a big roll up without a babysitter. come back and pick up a load of strait cut parts.:cool:

tom finck
07-14-2009, 06:59 PM
Any ideas where to get the plans for this or the parts

tattoomike68
07-14-2009, 07:08 PM
Any ideas where to get the plans for this or the parts


Not realy, I could make it faster then I could draw a print. how long are the parts and how many is a factor?

Forrest Addy
07-14-2009, 07:59 PM
Having straightened miles of old and new copper tube I have worked out the following for lengths up to 20 ft:

Find 2 pieces of plywood of suitable size. The plywood shoud be clean and unpainted.

Place one piece of plywood on a good floor.

Straighten the tube roughly with the fingers to take the whip out.

Place copper tube between the sheets.

Roll the copper tube between the plywood using your foot. Wet it a little for traction with the tube. Slide the tube along as you go. Don't try to straighten it all at once.

A little patience and maybe an anneal and you finish with straight copper tubing. Hurry it and you may squash it or kink it.

.

The Artful Bodger
07-14-2009, 08:11 PM
Forest Addy is the man! Roll it between pieces of wood....

tattoomike68
07-14-2009, 08:38 PM
Having straightened miles of old and new copper tube I have worked out the following for lengths up to 20 ft:

Find 2 pieces of plywood of suitable size. The plywood shoud be clean and unpainted.

Place one piece of plywood on a good floor.

Straighten the tube roughly with the fingers to take the whip out.

Place copper tube between the sheets.

Roll the copper tube between the plywood using your foot. Wet it a little for traction with the tube. Slide the tube along as you go. Don't try to straighten it all at once.

A little patience and maybe an anneal and you finish with straight copper tubing. Hurry it and you may squash it or kink it.

.

Are you sure? AfroAmerican engineering is my forte, normaly you would tell them to hire a crew of engineers and tool and die makes to do a simple task.

You fealing OK ?

Forrest Addy
07-14-2009, 08:45 PM
Hell, try it on a small scale. It works for solid copper wire too. The trick is not to rush it. And know when to anneal.

Take a piece of crooked small diameter solif copper wire or tube about a foot long and roll it between a couple of pieces of wood that's fairly flat.

websterz
07-14-2009, 08:45 PM
Are you sure? AfroAmerican engineering is my forte, normaly you would tell them to hire a crew of engineers and tool and die makes to do a simple task.

You fealing OK ?

Gee...THAT'S a great phrase to have floating around on the forum. When do we start with the Pollock jokes or start calling folks chinks and spicks?

Mcgyver
07-14-2009, 09:09 PM
didn't know Forrest's trick, neat. I've also tied one end to a tree and the other to a car and rocked the car a bit, more or less works but stretches a bit. here's one i made. has the advantage the the tube ends up hard so will take a thread, if thats of importance, and gets them very straight

http://i20.photobucket.com/albums/b201/michael0100/tube%20straightener/tubestraightener.jpg

more on it here

\\http://bbs.homeshopmachinist.net/showthread.php?t=24051

wierdscience
07-14-2009, 09:13 PM
When I have to straighten the small stuff I use a come-along and stretch it.It doesn't take much tonnage to do 3/8 roll copper and it yields perfectly straight lengths every time.Shorter lengths I do on the workbench by anchoring one end to the end of the bench top and clamping the other end in a modified pair of Vise-grips.The bolt in the vise grips is replaced with a length of all-thread which is slipped through an angle clip bolted to the opposite end of the bench.Thread on a nut and tighten it up.6' of copper requires less than 1/4" of elongation to straighten.

A side benefit of this method is the OD of the tube reduces very slightly which makes it easier to slip ferrules on.

The same method is used to straighten lead cane in stained glass work.

Rich Carlstedt
07-14-2009, 11:11 PM
Rolling the tube between two plates or boards is the way it has been done for ages.
I use a formica table top, and some plywood.
When you start, the tube wants to skid, so a thin sheet of rubber can help.
Once it rolls however, most of the "arcs" are gone and you can use harder surfaces to get pieces lazer straight.
You only need enough downward pressure to roll it.
The pressure you exercise is the most important work you do.
As it straightens, it gets harder and really bad pieces may need annealing.
You will feel it and know !
Rich

claudev
07-14-2009, 11:17 PM
A chemical company where I once worked used lots (probably miles) of small - mostly 1/4 and 3/8 inch copper tubing. Our standard method was to unroll a 50 foot coil, tie 1 end to a support column, the other to a 6 ft length of pipe used as a pry bar, then stretch it until it was straight. ( It only takes a slight amount of stretch.) We then cut off the buggered ends and the rest was cut to the needed length or into nominal 10 - 12 ft lengths for storage.

I suggest you try this method with a roll. If you are worried about diameter reduction then mike it before and after. I bet it will still be in spec and it will definitely be arrow straight.

Keep it simple. No tools required.

fixxit
07-15-2009, 01:40 AM
I have used a method similar to the sheets of plywood for straightening copper wire.
I place short lenghts of copper wire on a smooth flat floor, and roll the wire back and forth between my shoes and the floor.

A few passes back and forth does the trick.
(Flat leather sole shoes recommended.)
It really works.

Fixxit

tom finck
07-15-2009, 06:26 AM
Many thanks all. I think I will try to buy one, this will be used in a production job

Tom

Alistair Hosie
07-15-2009, 01:44 PM
I have heard of people filling the copper tube with dry sand so it doesn't kink that might be worth thinking about easily pours back out when finished.Alistair

Dawai
07-15-2009, 02:38 PM
Insanely easy.

Take a long spot where you can anchor one end, take a pry bar, wrap the copper around it and tie it. PRY it.

I had a piece of unistrut with the oblong holes, a steel bar with a round bar welded to the end to stick in the sequential holes and pry it..

Then I'd take the straightened copper and bend it up with instrument benders.