Boiler Build For American LaFrance Engine

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Well-Known Member
Aug 25, 2009
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Greeting, I have a thread started about the La France engine build under "A Work In Progress". What I would like to share here is some thoughts and feelings about my approach to the boiler for the La France. I did read through many of the postings under this topic and they were very encouraging about what I have in mind.

Basically, I am building the boiler from "Pressure Vessel Quality" materials except for the flue tubes. They will be copper. The reason for the all steel boiler is my skills for TIG welding is far better than my skills for silver soldering such a massive assembly and having everything stay in alignment.

The first picture shows a piece of 0.500" by 0.032" wall thickness that has been swaged into a piece of 0.250" thick steel that represents the flue tube sheets in my boiler. The hole in the 1/4" thick stock was reamed with a #1 taper pin reamer. The larger diameter of the hole would be on the none pressure side. The second picture shows the assembly next to a punch with the same amount of taper as the hole in the 1/4" stock. Next to the punch is a series of hardened steel balls that I had on hand; 0.625" dia., 0.875" dia., and 1.062" diameter. I used these balls in secession starting with the smaller ball first to flare the end of the tube outward. Then a small ball peen hammer was used to flatten the copper down to the surface of the 1/4" plate. I left 0.100" protruding from the 1/4" plate for this process. I do believe this process will work for my flue tube installation unless someone has any reservations.

The technical hurdle at this point is the punch. It was a bear to remove and I will not be able to remove it the way I did for this experiment when installing the flue tubes in the boiler assembly. So it is back to the drawing board on the punch. I am thinking along the lines of an expandable tool of some sorts ???

So please if you have any thoughts or question, fire away !

Swaged Flue Tube.jpg

Punch and Balls.jpg

Swaged Flue Tube.jpg

Punch and Balls.jpg
Hi steamin,
I don't have any reservations, but I do think it's worth noting that historically (and in the present day) copper tubes in steel boilers has been a very common combination which has always worked well. Also, historically (and presently) copper tubes were simply rolled (ie, expanded) in to straight reamed holes without further treatment and this too has worked well. Some builders follow this with silver soldering the flues but this is a matter of personal preference and the larger percentage of builders don't. If weeps occur the remedy is to re-roll the weepy flue. That being the case, for the labor involved, I would question whether flanging over as you proposed has a benefit beyond simple rolling in.
Sir Harry, I do appreciate your comments. I was wondering if the flanging over of the end of the tube might be gilding the lillie so to speak. The only reason I chose to use a taper hole to swage into was that I do not have a tube roller that small available to me. So I thought why not expand a little bit into a taper hole. I guess I will put on the ole thinking cap and see if I can come up with something like you have suggested and go with the reamed straight hole concept.

Thanks again ;D
I've thought about trying it this way too. I've heard guys say it works. Bill Harris had a method to use rubber washers compressed with a nut and bolt to expand tubes into straight reamed holes.

I would think there is more then one way to skin the cat.

A steel boiler experiment is in my future. I appreciate you taking time to do this write-up.

Thanks, Bob

"gilding the lillie" (??)
Would someone mind describing what a tube roller is and how it works?

I can attest to Bill Harris's rubber washer method. When I expanded my tubes you could actually see the finish marks left by the reamer in the tube sheet holes, transferred into the I.D. of the copper tube. I have done probably 50 tubes this way and only had one leaker which was easily fixed by expanding it a little more.

So I am guessing that some facet washers were stacked together with a nut and washer on either side and they were squeezed until there was no more to squeeze ???? The copper tube I have is half hard and may take something more rigid to really seal the tube in the tube sheet.

There are 2 pictures of a tube roller for 1/2" ID copper tubing. There are 3 tapered steel rollers captured in the body of the mechanism. A shaft runs length wise through the main body. The shaft has a mating taper in contact with the 3 rollers. The roller portion is placed inside the flue. The shaft is slowly turned by hand. The rollers are on a slight angle so as the shaft is turned the rollers turn and expand inside the flue tube and the main body rotates inside the flue tube. There is a steel collar that keeps the main body in place as the process proceeds.

I had to generate the outer shell of the boiler so I could mount the frame to build the suspension. When I get back to the boiler build I'll post some pictures.

"Gild the lily" is an old phrase pertaining to doing something in excess or going over board or doing more than what is necessary to accomplish a task.


Here is Bill Harris's method with a test pressure vessel for practice. This picture is from his 1.5" scale Steam Roller plan book. The rod that compresses the rubber washers is 3/8" diameter, turned and threaded for 1/4 x 28. Length, as needed.

{image gone}
Hi Bob, Thanks a lot. I do appreciate it. I will give it a try.
steamin said:
Hi Bob, Thanks a lot. I do appreciate it. I will give it a try.

Sometime this year I want to build the boiler Harris did for his steam roller. Purely for experiment and practice welding. It is from 4" Sch 40 steel pipe with 8 each, 5/8" diameter copper flues. I am going to try your method and Harris', 4 flues each.

Thanks for showing your method. Bob
Hey guys,

Lets not post pictures from other copywrite sources OK......I suggest you take that on down please...Sorry.
If you can't let me know.

If you want to convey that idea then sketch it up yourself and post it.....but no copies....

steamer said:
Hey guys,

Lets not post pictures from other copywrite sources OK......I suggest you take that on down please...Sorry.
If you can't let me know.

If you want to convey that idea then sketch it up yourself and post it.....but no copies....


WILCO, done
Thanks Guys....

I'm looking forward to this thread.... ;D I got a soft spot for pumpers!

Sir JasonB, thank you so very much for the catalog link. It has given me one point of very valuable information. The tube OD I was planning to use is to large for the thickness of my tube sheets. I was going to use .500" OD copper tube with a wall thickness of 0.032" in a .250" thick steel tube sheet. The chart for a "C" Type 900 Series has indicated that a .375" OD is the maximum one should go for the .250" thick tube sheet. The diagrams also show that the tube ends are flush with the non-pressure side of the tube sheet unless you do plan to bead the end of the tube. So, again I do appreciate the information.

I hope I am not confusing folks with my posting of this build on 3 different threads. Yes, I have been posting on Smokstak about this steam pumper since I started this project over 16 months ago and will continue to do so. I was also encouraged at the recent "Cabin Fever Expo" to share with you folks within this forum. So there is a thread of this build in the "A Work In Progress" section. I jumped over to this section because of "Boiler" specific questions that I had. I plan to keep the boiler build within the confines of this thread and will post the overall build in the other two threads that I have going.

I do appreciate your comments, support and interest.
They do make expanders for projecting ends, have a look at the second one down, All the boilers I have seen with expanded tubes have a small projection but not flared out. Personally I can't see the point in flaring the ends with copper in a steel boiler, it won't add to the staying as the copper will have expanded more lengthways than the boiler barrel when its hot.

This thread shows a boiler being tubed.

What an awesome build! Thanks for the direction Jason.

I really like your solutions to some of the part problems. The lathe set up for the spokes is quite inspiring.

Keep it coming...I'm loving it.

Hi JasonB, My only concern about a flue tube protruding, especially on the fire side, would be the end of the tube over heating and causing some damage to the tube. The protruding portion would not be in contact with the tube sheet which would act like a heat sink back to the water. In my way of thinking, flush, bead or no protrusion at all.

Jason, would you have any idea what the cost would be for a tube roller that I mentioned earlier or is that a taboo thing to do on this forum.

Dave, sure thing !
No need to get a tube expander from the UK unless you live there. Google tube expander for US sources. McMaster & Carr has them but only down to 1/2" OD.

Here is a link to US firm with an 800 number.

I drew 2 boilers for Shay locomotives with copper fire boxes and brass tubes that went to Australia. The detail inset shows the tube end rolled and belled at the firebox end. Steel ferrules also with a belled end were inserted to protect the tube ends from the the effects of hot gas. The boilers were built to the Board of Trade Rules of 1905 and 1907.