3/4" OD copper K type tube Roller

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Greg_Lewis
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Re: 3/4" OD copper K type tube Roller

Post by Greg_Lewis »

I think you have to decide how many boilers you plan to build. For those of us who only build one or two boilers, a shop-built roller will work just fine. I wrote up a design by John Bailie which was published in Live Steam. I made one and it worked great. I'll send along the plans to anyone who p.m.s me with an email address.
Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
duckman903
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Re: 3/4" OD copper K type tube Roller

Post by duckman903 »

I would like a set of plans my e-mail is
tmccune4@gmail.com
dkellldog
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Re: 3/4" OD copper K type tube Roller

Post by dkellldog »

Lots of talented people on this thread and I appreciate being able to stand on your shoulders.
For 3/4" and 1-1/4" type L copper tubing, all the literature typically allows for a .010" clearance hole in the tube sheets. With the 3/4" tube having an OD of .875", would a 22.5 mm (.8858") reamer be appropriate? For the 1-1/4" copper tube, would a 35 mm (1.3779") metric reamer be appropriate for the 1.375" OD tube? How far off can the tube tolerance be?
It's a new boiler but I've had to tear it apart once as the 1980's literature published in the hobbyist magazines had the ligaments specified at 1/4". At that time I was going to use steel tubes 1" and 1-1/2" in diameter. These tubes were too large for such a skinny ligament. I don't want to make another mistake, the scrap bin is full and the wallet is running dry.
Marty_Knox
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Re: 3/4" OD copper K type tube Roller

Post by Marty_Knox »

Those size reamers should work. I think you may have misunderstood the ligament recommendation. I have always used 1/4 of the tube diameter. That would be 1/4" for a 1" diameter tube. Larger diameter tubes need a larger ligament.
Johnny O
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Re: 3/4" OD copper K type tube Roller

Post by Johnny O »

Marty, do you ever allow that ligament to go below 1/4”. I did my home work on this and upon finishing my tube sheets I noticed my outer holes were too close to weld zone. I looked up specs on sugartech.com and the cinder sniffers site. I .625 O.D. tubes on an .813 pitch. My .188 ligament looked good. I even fabricated a test piece and rolled tubes to verify no distortion. However, after some thought about corrosion and good boiler maint. I decided to follow the cinder sniffers statement of not going below 1/4” ligament thickness. I’ve seen pics of cut open boilers and they were packed with corrosive build up. I remade my sheets with four less tubes and 1/4” ligaments. The calculated min. of .156 may only lead to shorter boiler life. My two cents. Love your work by the way, very impressive.
Marty_Knox
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Re: 3/4" OD copper K type tube Roller

Post by Marty_Knox »

Yes, I use ligaments less than 1/4". I try to keep at least 3/16" away from any edge. But it is a compromise between getting enough tubes and getting tubes too close together.
I like to make the water legs at least 1/2" wide. The original Allen Mogul uses 3/8" water legs. I have seen many of these fail because the water space is clogged with scale.
Pontiacguy1
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Re: 3/4" OD copper K type tube Roller

Post by Pontiacguy1 »

Like This:
20190730_165451b.jpg
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NP317
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Re: 3/4" OD copper K type tube Roller

Post by NP317 »

Ouch!
'Sure promotes using water treatment and periodic comprehensive washouts.
RussN
Marty_Knox
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Re: 3/4" OD copper K type tube Roller

Post by Marty_Knox »

Marty_Knox wrote: Wed Jan 27, 2021 10:18 am Those size reamers should work. I think you may have misunderstood the ligament recommendation. I have always used 1/4 of the tube diameter. That would be 1/4" for a 1" diameter tube. Larger diameter tubes need a larger ligament.
I should have said that those sizes work for the front tube sheet. I ream the rear tube sheet to the nominal size. This way the tube slides through the front tube sheet easily but is a wring fit in the rear. I then roll the front and most of the time don't have to clamp the rear.
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Fender
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Re: 3/4" OD copper K type tube Roller

Post by Fender »

I would also suggest beveling the tubes slightly on the OD on the firebox end, to make them easier to start into the firebox tube sheet. Use a rubber hammer to drive them in.
Dan Watson
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Bill Shields
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Re: 3/4" OD copper K type tube Roller

Post by Bill Shields »

and if they don't go...get a bigger hammer!

nothing like mashing a tube before you get it in place and start rolling! :shock:
Too many things going on to bother listing them.
Johnny O
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Re: 3/4" OD copper K type tube Roller

Post by Johnny O »

I must agree that the tube holes should be large enough to accommodate any misalignment in the assembly of the boiler components. the question is how much over size can one get away with. I'm not there yet but I am getting close.
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